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Willy Tarreau2212e6a2015-10-13 14:40:55 +02001 ------------------------
2 HAProxy Management Guide
3 ------------------------
Willy Tarreau1db55792020-11-05 17:20:35 +01004 version 2.4
Willy Tarreau2212e6a2015-10-13 14:40:55 +02005
6
7This document describes how to start, stop, manage, and troubleshoot HAProxy,
8as well as some known limitations and traps to avoid. It does not describe how
9to configure it (for this please read configuration.txt).
10
11Note to documentation contributors :
12 This document is formatted with 80 columns per line, with even number of
13 spaces for indentation and without tabs. Please follow these rules strictly
14 so that it remains easily printable everywhere. If you add sections, please
15 update the summary below for easier searching.
16
17
18Summary
19-------
20
211. Prerequisites
222. Quick reminder about HAProxy's architecture
233. Starting HAProxy
244. Stopping and restarting HAProxy
255. File-descriptor limitations
266. Memory management
277. CPU usage
288. Logging
299. Statistics and monitoring
Willy Tarreau44aed902015-10-13 14:45:29 +0200309.1. CSV format
Willy Tarreau5d8b9792016-03-11 11:09:34 +0100319.2. Typed output format
329.3. Unix Socket commands
William Lallemand142db372018-12-11 18:56:45 +0100339.4. Master CLI
Willy Tarreau2212e6a2015-10-13 14:40:55 +02003410. Tricks for easier configuration management
3511. Well-known traps to avoid
3612. Debugging and performance issues
3713. Security considerations
38
39
401. Prerequisites
41----------------
42
43In this document it is assumed that the reader has sufficient administration
44skills on a UNIX-like operating system, uses the shell on a daily basis and is
45familiar with troubleshooting utilities such as strace and tcpdump.
46
47
482. Quick reminder about HAProxy's architecture
49----------------------------------------------
50
Willy Tarreau3f364482019-02-27 15:01:46 +010051HAProxy is a multi-threaded, event-driven, non-blocking daemon. This means is
Willy Tarreau2212e6a2015-10-13 14:40:55 +020052uses event multiplexing to schedule all of its activities instead of relying on
53the system to schedule between multiple activities. Most of the time it runs as
54a single process, so the output of "ps aux" on a system will report only one
55"haproxy" process, unless a soft reload is in progress and an older process is
56finishing its job in parallel to the new one. It is thus always easy to trace
Willy Tarreau3f364482019-02-27 15:01:46 +010057its activity using the strace utility. In order to scale with the number of
58available processors, by default haproxy will start one worker thread per
59processor it is allowed to run on. Unless explicitly configured differently,
60the incoming traffic is spread over all these threads, all running the same
61event loop. A great care is taken to limit inter-thread dependencies to the
62strict minimum, so as to try to achieve near-linear scalability. This has some
63impacts such as the fact that a given connection is served by a single thread.
64Thus in order to use all available processing capacity, it is needed to have at
65least as many connections as there are threads, which is almost always granted.
Willy Tarreau2212e6a2015-10-13 14:40:55 +020066
67HAProxy is designed to isolate itself into a chroot jail during startup, where
68it cannot perform any file-system access at all. This is also true for the
69libraries it depends on (eg: libc, libssl, etc). The immediate effect is that
70a running process will not be able to reload a configuration file to apply
71changes, instead a new process will be started using the updated configuration
72file. Some other less obvious effects are that some timezone files or resolver
73files the libc might attempt to access at run time will not be found, though
74this should generally not happen as they're not needed after startup. A nice
75consequence of this principle is that the HAProxy process is totally stateless,
76and no cleanup is needed after it's killed, so any killing method that works
77will do the right thing.
78
79HAProxy doesn't write log files, but it relies on the standard syslog protocol
80to send logs to a remote server (which is often located on the same system).
81
82HAProxy uses its internal clock to enforce timeouts, that is derived from the
83system's time but where unexpected drift is corrected. This is done by limiting
84the time spent waiting in poll() for an event, and measuring the time it really
85took. In practice it never waits more than one second. This explains why, when
86running strace over a completely idle process, periodic calls to poll() (or any
87of its variants) surrounded by two gettimeofday() calls are noticed. They are
88normal, completely harmless and so cheap that the load they imply is totally
89undetectable at the system scale, so there's nothing abnormal there. Example :
90
91 16:35:40.002320 gettimeofday({1442759740, 2605}, NULL) = 0
92 16:35:40.002942 epoll_wait(0, {}, 200, 1000) = 0
93 16:35:41.007542 gettimeofday({1442759741, 7641}, NULL) = 0
94 16:35:41.007998 gettimeofday({1442759741, 8114}, NULL) = 0
95 16:35:41.008391 epoll_wait(0, {}, 200, 1000) = 0
96 16:35:42.011313 gettimeofday({1442759742, 11411}, NULL) = 0
97
98HAProxy is a TCP proxy, not a router. It deals with established connections that
99have been validated by the kernel, and not with packets of any form nor with
100sockets in other states (eg: no SYN_RECV nor TIME_WAIT), though their existence
101may prevent it from binding a port. It relies on the system to accept incoming
102connections and to initiate outgoing connections. An immediate effect of this is
103that there is no relation between packets observed on the two sides of a
104forwarded connection, which can be of different size, numbers and even family.
105Since a connection may only be accepted from a socket in LISTEN state, all the
106sockets it is listening to are necessarily visible using the "netstat" utility
107to show listening sockets. Example :
108
109 # netstat -ltnp
110 Active Internet connections (only servers)
111 Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program name
112 tcp 0 0 0.0.0.0:22 0.0.0.0:* LISTEN 1629/sshd
113 tcp 0 0 0.0.0.0:80 0.0.0.0:* LISTEN 2847/haproxy
114 tcp 0 0 0.0.0.0:443 0.0.0.0:* LISTEN 2847/haproxy
115
116
1173. Starting HAProxy
118-------------------
119
120HAProxy is started by invoking the "haproxy" program with a number of arguments
121passed on the command line. The actual syntax is :
122
123 $ haproxy [<options>]*
124
125where [<options>]* is any number of options. An option always starts with '-'
126followed by one of more letters, and possibly followed by one or multiple extra
127arguments. Without any option, HAProxy displays the help page with a reminder
128about supported options. Available options may vary slightly based on the
129operating system. A fair number of these options overlap with an equivalent one
130if the "global" section. In this case, the command line always has precedence
131over the configuration file, so that the command line can be used to quickly
132enforce some settings without touching the configuration files. The current
133list of options is :
134
135 -- <cfgfile>* : all the arguments following "--" are paths to configuration
Maxime de Roucy379d9c72016-05-13 23:52:56 +0200136 file/directory to be loaded and processed in the declaration order. It is
137 mostly useful when relying on the shell to load many files that are
138 numerically ordered. See also "-f". The difference between "--" and "-f" is
139 that one "-f" must be placed before each file name, while a single "--" is
140 needed before all file names. Both options can be used together, the
141 command line ordering still applies. When more than one file is specified,
142 each file must start on a section boundary, so the first keyword of each
143 file must be one of "global", "defaults", "peers", "listen", "frontend",
144 "backend", and so on. A file cannot contain just a server list for example.
Willy Tarreau2212e6a2015-10-13 14:40:55 +0200145
Maxime de Roucy379d9c72016-05-13 23:52:56 +0200146 -f <cfgfile|cfgdir> : adds <cfgfile> to the list of configuration files to be
147 loaded. If <cfgdir> is a directory, all the files (and only files) it
Dan Lloyd8e48b872016-07-01 21:01:18 -0400148 contains are added in lexical order (using LC_COLLATE=C) to the list of
Maxime de Roucy379d9c72016-05-13 23:52:56 +0200149 configuration files to be loaded ; only files with ".cfg" extension are
150 added, only non hidden files (not prefixed with ".") are added.
151 Configuration files are loaded and processed in their declaration order.
152 This option may be specified multiple times to load multiple files. See
153 also "--". The difference between "--" and "-f" is that one "-f" must be
154 placed before each file name, while a single "--" is needed before all file
155 names. Both options can be used together, the command line ordering still
156 applies. When more than one file is specified, each file must start on a
157 section boundary, so the first keyword of each file must be one of
158 "global", "defaults", "peers", "listen", "frontend", "backend", and so on.
159 A file cannot contain just a server list for example.
Willy Tarreau2212e6a2015-10-13 14:40:55 +0200160
161 -C <dir> : changes to directory <dir> before loading configuration
162 files. This is useful when using relative paths. Warning when using
163 wildcards after "--" which are in fact replaced by the shell before
164 starting haproxy.
165
166 -D : start as a daemon. The process detaches from the current terminal after
167 forking, and errors are not reported anymore in the terminal. It is
168 equivalent to the "daemon" keyword in the "global" section of the
169 configuration. It is recommended to always force it in any init script so
170 that a faulty configuration doesn't prevent the system from booting.
171
Willy Tarreau2212e6a2015-10-13 14:40:55 +0200172 -L <name> : change the local peer name to <name>, which defaults to the local
William Lallemanddaf4cd22018-04-17 16:46:13 +0200173 hostname. This is used only with peers replication. You can use the
174 variable $HAPROXY_LOCALPEER in the configuration file to reference the
175 peer name.
Willy Tarreau2212e6a2015-10-13 14:40:55 +0200176
177 -N <limit> : sets the default per-proxy maxconn to <limit> instead of the
178 builtin default value (usually 2000). Only useful for debugging.
179
180 -V : enable verbose mode (disables quiet mode). Reverts the effect of "-q" or
181 "quiet".
182
William Lallemande202b1e2017-06-01 17:38:56 +0200183 -W : master-worker mode. It is equivalent to the "master-worker" keyword in
184 the "global" section of the configuration. This mode will launch a "master"
185 which will monitor the "workers". Using this mode, you can reload HAProxy
186 directly by sending a SIGUSR2 signal to the master. The master-worker mode
187 is compatible either with the foreground or daemon mode. It is
188 recommended to use this mode with multiprocess and systemd.
189
Pavlos Parissisf65f2572018-02-07 21:42:16 +0100190 -Ws : master-worker mode with support of `notify` type of systemd service.
191 This option is only available when HAProxy was built with `USE_SYSTEMD`
192 build option enabled.
193
Willy Tarreau2212e6a2015-10-13 14:40:55 +0200194 -c : only performs a check of the configuration files and exits before trying
195 to bind. The exit status is zero if everything is OK, or non-zero if an
Willy Tarreaubebd2122020-04-15 16:06:11 +0200196 error is encountered. Presence of warnings will be reported if any.
Willy Tarreau2212e6a2015-10-13 14:40:55 +0200197
198 -d : enable debug mode. This disables daemon mode, forces the process to stay
Willy Tarreauccf42992020-10-09 19:15:03 +0200199 in foreground and to show incoming and outgoing events. It must never be
200 used in an init script.
Willy Tarreau2212e6a2015-10-13 14:40:55 +0200201
Amaury Denoyelle7b01a8d2021-03-29 10:29:07 +0200202 -dD : enable diagnostic mode. This mode will output extra warnings about
203 suspicious configuration statements. This will never prevent startup even in
204 "zero-warning" mode nor change the exit status code.
205
Willy Tarreau2212e6a2015-10-13 14:40:55 +0200206 -dG : disable use of getaddrinfo() to resolve host names into addresses. It
207 can be used when suspecting that getaddrinfo() doesn't work as expected.
208 This option was made available because many bogus implementations of
209 getaddrinfo() exist on various systems and cause anomalies that are
210 difficult to troubleshoot.
211
Dan Lloyd8e48b872016-07-01 21:01:18 -0400212 -dM[<byte>] : forces memory poisoning, which means that each and every
Willy Tarreaubafbe012017-11-24 17:34:44 +0100213 memory region allocated with malloc() or pool_alloc() will be filled with
Willy Tarreau2212e6a2015-10-13 14:40:55 +0200214 <byte> before being passed to the caller. When <byte> is not specified, it
215 defaults to 0x50 ('P'). While this slightly slows down operations, it is
216 useful to reliably trigger issues resulting from missing initializations in
217 the code that cause random crashes. Note that -dM0 has the effect of
218 turning any malloc() into a calloc(). In any case if a bug appears or
219 disappears when using this option it means there is a bug in haproxy, so
220 please report it.
221
222 -dS : disable use of the splice() system call. It is equivalent to the
223 "global" section's "nosplice" keyword. This may be used when splice() is
224 suspected to behave improperly or to cause performance issues, or when
225 using strace to see the forwarded data (which do not appear when using
226 splice()).
227
228 -dV : disable SSL verify on the server side. It is equivalent to having
229 "ssl-server-verify none" in the "global" section. This is useful when
230 trying to reproduce production issues out of the production
231 environment. Never use this in an init script as it degrades SSL security
232 to the servers.
233
Willy Tarreau3eb10b82020-04-15 16:42:39 +0200234 -dW : if set, haproxy will refuse to start if any warning was emitted while
235 processing the configuration. This helps detect subtle mistakes and keep the
236 configuration clean and portable across versions. It is recommended to set
237 this option in service scripts when configurations are managed by humans,
238 but it is recommended not to use it with generated configurations, which
239 tend to emit more warnings. It may be combined with "-c" to cause warnings
240 in checked configurations to fail. This is equivalent to global option
241 "zero-warning".
242
Willy Tarreau2212e6a2015-10-13 14:40:55 +0200243 -db : disable background mode and multi-process mode. The process remains in
244 foreground. It is mainly used during development or during small tests, as
245 Ctrl-C is enough to stop the process. Never use it in an init script.
246
247 -de : disable the use of the "epoll" poller. It is equivalent to the "global"
248 section's keyword "noepoll". It is mostly useful when suspecting a bug
249 related to this poller. On systems supporting epoll, the fallback will
250 generally be the "poll" poller.
251
252 -dk : disable the use of the "kqueue" poller. It is equivalent to the
253 "global" section's keyword "nokqueue". It is mostly useful when suspecting
254 a bug related to this poller. On systems supporting kqueue, the fallback
255 will generally be the "poll" poller.
256
257 -dp : disable the use of the "poll" poller. It is equivalent to the "global"
258 section's keyword "nopoll". It is mostly useful when suspecting a bug
259 related to this poller. On systems supporting poll, the fallback will
260 generally be the "select" poller, which cannot be disabled and is limited
261 to 1024 file descriptors.
262
Willy Tarreau3eed10e2016-11-07 21:03:16 +0100263 -dr : ignore server address resolution failures. It is very common when
264 validating a configuration out of production not to have access to the same
265 resolvers and to fail on server address resolution, making it difficult to
266 test a configuration. This option simply appends the "none" method to the
267 list of address resolution methods for all servers, ensuring that even if
268 the libc fails to resolve an address, the startup sequence is not
269 interrupted.
270
Willy Tarreau70060452015-12-14 12:46:07 +0100271 -m <limit> : limit the total allocatable memory to <limit> megabytes across
272 all processes. This may cause some connection refusals or some slowdowns
Willy Tarreau2212e6a2015-10-13 14:40:55 +0200273 depending on the amount of memory needed for normal operations. This is
Willy Tarreau70060452015-12-14 12:46:07 +0100274 mostly used to force the processes to work in a constrained resource usage
275 scenario. It is important to note that the memory is not shared between
276 processes, so in a multi-process scenario, this value is first divided by
277 global.nbproc before forking.
Willy Tarreau2212e6a2015-10-13 14:40:55 +0200278
279 -n <limit> : limits the per-process connection limit to <limit>. This is
280 equivalent to the global section's keyword "maxconn". It has precedence
281 over this keyword. This may be used to quickly force lower limits to avoid
282 a service outage on systems where resource limits are too low.
283
284 -p <file> : write all processes' pids into <file> during startup. This is
285 equivalent to the "global" section's keyword "pidfile". The file is opened
286 before entering the chroot jail, and after doing the chdir() implied by
287 "-C". Each pid appears on its own line.
288
289 -q : set "quiet" mode. This disables some messages during the configuration
290 parsing and during startup. It can be used in combination with "-c" to
291 just check if a configuration file is valid or not.
292
William Lallemand142db372018-12-11 18:56:45 +0100293 -S <bind>[,bind_options...]: in master-worker mode, bind a master CLI, which
294 allows the access to every processes, running or leaving ones.
295 For security reasons, it is recommended to bind the master CLI to a local
296 UNIX socket. The bind options are the same as the keyword "bind" in
297 the configuration file with words separated by commas instead of spaces.
298
299 Note that this socket can't be used to retrieve the listening sockets from
300 an old process during a seamless reload.
301
Willy Tarreau2212e6a2015-10-13 14:40:55 +0200302 -sf <pid>* : send the "finish" signal (SIGUSR1) to older processes after boot
303 completion to ask them to finish what they are doing and to leave. <pid>
304 is a list of pids to signal (one per argument). The list ends on any
305 option starting with a "-". It is not a problem if the list of pids is
306 empty, so that it can be built on the fly based on the result of a command
307 like "pidof" or "pgrep".
308
309 -st <pid>* : send the "terminate" signal (SIGTERM) to older processes after
310 boot completion to terminate them immediately without finishing what they
311 were doing. <pid> is a list of pids to signal (one per argument). The list
312 is ends on any option starting with a "-". It is not a problem if the list
313 of pids is empty, so that it can be built on the fly based on the result of
314 a command like "pidof" or "pgrep".
315
316 -v : report the version and build date.
317
318 -vv : display the version, build options, libraries versions and usable
319 pollers. This output is systematically requested when filing a bug report.
320
Olivier Houchardd33fc3a2017-04-05 22:50:59 +0200321 -x <unix_socket> : connect to the specified socket and try to retrieve any
322 listening sockets from the old process, and use them instead of trying to
323 bind new ones. This is useful to avoid missing any new connection when
William Lallemandf6975e92017-05-26 17:42:10 +0200324 reloading the configuration on Linux. The capability must be enable on the
325 stats socket using "expose-fd listeners" in your configuration.
Olivier Houchardd33fc3a2017-04-05 22:50:59 +0200326
Dan Lloyd8e48b872016-07-01 21:01:18 -0400327A safe way to start HAProxy from an init file consists in forcing the daemon
Willy Tarreau2212e6a2015-10-13 14:40:55 +0200328mode, storing existing pids to a pid file and using this pid file to notify
329older processes to finish before leaving :
330
331 haproxy -f /etc/haproxy.cfg \
332 -D -p /var/run/haproxy.pid -sf $(cat /var/run/haproxy.pid)
333
334When the configuration is split into a few specific files (eg: tcp vs http),
335it is recommended to use the "-f" option :
336
337 haproxy -f /etc/haproxy/global.cfg -f /etc/haproxy/stats.cfg \
338 -f /etc/haproxy/default-tcp.cfg -f /etc/haproxy/tcp.cfg \
339 -f /etc/haproxy/default-http.cfg -f /etc/haproxy/http.cfg \
340 -D -p /var/run/haproxy.pid -sf $(cat /var/run/haproxy.pid)
341
342When an unknown number of files is expected, such as customer-specific files,
343it is recommended to assign them a name starting with a fixed-size sequence
344number and to use "--" to load them, possibly after loading some defaults :
345
346 haproxy -f /etc/haproxy/global.cfg -f /etc/haproxy/stats.cfg \
347 -f /etc/haproxy/default-tcp.cfg -f /etc/haproxy/tcp.cfg \
348 -f /etc/haproxy/default-http.cfg -f /etc/haproxy/http.cfg \
349 -D -p /var/run/haproxy.pid -sf $(cat /var/run/haproxy.pid) \
350 -f /etc/haproxy/default-customers.cfg -- /etc/haproxy/customers/*
351
352Sometimes a failure to start may happen for whatever reason. Then it is
353important to verify if the version of HAProxy you are invoking is the expected
354version and if it supports the features you are expecting (eg: SSL, PCRE,
355compression, Lua, etc). This can be verified using "haproxy -vv". Some
356important information such as certain build options, the target system and
357the versions of the libraries being used are reported there. It is also what
358you will systematically be asked for when posting a bug report :
359
360 $ haproxy -vv
Willy Tarreau58000fe2021-05-09 06:25:16 +0200361 HAProxy version 1.6-dev7-a088d3-4 2015/10/08
Willy Tarreau2212e6a2015-10-13 14:40:55 +0200362 Copyright 2000-2015 Willy Tarreau <willy@haproxy.org>
363
364 Build options :
365 TARGET = linux2628
366 CPU = generic
367 CC = gcc
368 CFLAGS = -pg -O0 -g -fno-strict-aliasing -Wdeclaration-after-statement \
369 -DBUFSIZE=8030 -DMAXREWRITE=1030 -DSO_MARK=36 -DTCP_REPAIR=19
370 OPTIONS = USE_ZLIB=1 USE_DLMALLOC=1 USE_OPENSSL=1 USE_LUA=1 USE_PCRE=1
371
372 Default settings :
373 maxconn = 2000, bufsize = 8030, maxrewrite = 1030, maxpollevents = 200
374
375 Encrypted password support via crypt(3): yes
376 Built with zlib version : 1.2.6
377 Compression algorithms supported : identity("identity"), deflate("deflate"), \
378 raw-deflate("deflate"), gzip("gzip")
379 Built with OpenSSL version : OpenSSL 1.0.1o 12 Jun 2015
380 Running on OpenSSL version : OpenSSL 1.0.1o 12 Jun 2015
381 OpenSSL library supports TLS extensions : yes
382 OpenSSL library supports SNI : yes
383 OpenSSL library supports prefer-server-ciphers : yes
384 Built with PCRE version : 8.12 2011-01-15
385 PCRE library supports JIT : no (USE_PCRE_JIT not set)
386 Built with Lua version : Lua 5.3.1
387 Built with transparent proxy support using: IP_TRANSPARENT IP_FREEBIND
388
389 Available polling systems :
390 epoll : pref=300, test result OK
391 poll : pref=200, test result OK
392 select : pref=150, test result OK
393 Total: 3 (3 usable), will use epoll.
394
395The relevant information that many non-developer users can verify here are :
396 - the version : 1.6-dev7-a088d3-4 above means the code is currently at commit
397 ID "a088d3" which is the 4th one after after official version "1.6-dev7".
398 Version 1.6-dev7 would show as "1.6-dev7-8c1ad7". What matters here is in
399 fact "1.6-dev7". This is the 7th development version of what will become
400 version 1.6 in the future. A development version not suitable for use in
401 production (unless you know exactly what you are doing). A stable version
402 will show as a 3-numbers version, such as "1.5.14-16f863", indicating the
403 14th level of fix on top of version 1.5. This is a production-ready version.
404
405 - the release date : 2015/10/08. It is represented in the universal
406 year/month/day format. Here this means August 8th, 2015. Given that stable
407 releases are issued every few months (1-2 months at the beginning, sometimes
408 6 months once the product becomes very stable), if you're seeing an old date
409 here, it means you're probably affected by a number of bugs or security
410 issues that have since been fixed and that it might be worth checking on the
411 official site.
412
413 - build options : they are relevant to people who build their packages
414 themselves, they can explain why things are not behaving as expected. For
415 example the development version above was built for Linux 2.6.28 or later,
Dan Lloyd8e48b872016-07-01 21:01:18 -0400416 targeting a generic CPU (no CPU-specific optimizations), and lacks any
Willy Tarreau2212e6a2015-10-13 14:40:55 +0200417 code optimization (-O0) so it will perform poorly in terms of performance.
418
419 - libraries versions : zlib version is reported as found in the library
420 itself. In general zlib is considered a very stable product and upgrades
421 are almost never needed. OpenSSL reports two versions, the version used at
422 build time and the one being used, as found on the system. These ones may
423 differ by the last letter but never by the numbers. The build date is also
424 reported because most OpenSSL bugs are security issues and need to be taken
425 seriously, so this library absolutely needs to be kept up to date. Seeing a
426 4-months old version here is highly suspicious and indeed an update was
427 missed. PCRE provides very fast regular expressions and is highly
428 recommended. Certain of its extensions such as JIT are not present in all
429 versions and still young so some people prefer not to build with them,
Dan Lloyd8e48b872016-07-01 21:01:18 -0400430 which is why the build status is reported as well. Regarding the Lua
Willy Tarreau2212e6a2015-10-13 14:40:55 +0200431 scripting language, HAProxy expects version 5.3 which is very young since
432 it was released a little time before HAProxy 1.6. It is important to check
433 on the Lua web site if some fixes are proposed for this branch.
434
435 - Available polling systems will affect the process's scalability when
436 dealing with more than about one thousand of concurrent connections. These
437 ones are only available when the correct system was indicated in the TARGET
438 variable during the build. The "epoll" mechanism is highly recommended on
439 Linux, and the kqueue mechanism is highly recommended on BSD. Lacking them
440 will result in poll() or even select() being used, causing a high CPU usage
441 when dealing with a lot of connections.
442
443
4444. Stopping and restarting HAProxy
445----------------------------------
446
447HAProxy supports a graceful and a hard stop. The hard stop is simple, when the
448SIGTERM signal is sent to the haproxy process, it immediately quits and all
449established connections are closed. The graceful stop is triggered when the
450SIGUSR1 signal is sent to the haproxy process. It consists in only unbinding
451from listening ports, but continue to process existing connections until they
452close. Once the last connection is closed, the process leaves.
453
454The hard stop method is used for the "stop" or "restart" actions of the service
455management script. The graceful stop is used for the "reload" action which
456tries to seamlessly reload a new configuration in a new process.
457
458Both of these signals may be sent by the new haproxy process itself during a
459reload or restart, so that they are sent at the latest possible moment and only
460if absolutely required. This is what is performed by the "-st" (hard) and "-sf"
461(graceful) options respectively.
462
William Lallemande202b1e2017-06-01 17:38:56 +0200463In master-worker mode, it is not needed to start a new haproxy process in
464order to reload the configuration. The master process reacts to the SIGUSR2
465signal by reexecuting itself with the -sf parameter followed by the PIDs of
466the workers. The master will then parse the configuration file and fork new
467workers.
468
Willy Tarreau2212e6a2015-10-13 14:40:55 +0200469To understand better how these signals are used, it is important to understand
470the whole restart mechanism.
471
472First, an existing haproxy process is running. The administrator uses a system
Jackie Tapia749f74c2020-07-22 18:59:40 -0500473specific command such as "/etc/init.d/haproxy reload" to indicate they want to
Willy Tarreau2212e6a2015-10-13 14:40:55 +0200474take the new configuration file into effect. What happens then is the following.
475First, the service script (/etc/init.d/haproxy or equivalent) will verify that
476the configuration file parses correctly using "haproxy -c". After that it will
477try to start haproxy with this configuration file, using "-st" or "-sf".
478
479Then HAProxy tries to bind to all listening ports. If some fatal errors happen
480(eg: address not present on the system, permission denied), the process quits
481with an error. If a socket binding fails because a port is already in use, then
482the process will first send a SIGTTOU signal to all the pids specified in the
483"-st" or "-sf" pid list. This is what is called the "pause" signal. It instructs
484all existing haproxy processes to temporarily stop listening to their ports so
485that the new process can try to bind again. During this time, the old process
486continues to process existing connections. If the binding still fails (because
487for example a port is shared with another daemon), then the new process sends a
488SIGTTIN signal to the old processes to instruct them to resume operations just
489as if nothing happened. The old processes will then restart listening to the
490ports and continue to accept connections. Not that this mechanism is system
Dan Lloyd8e48b872016-07-01 21:01:18 -0400491dependent and some operating systems may not support it in multi-process mode.
Willy Tarreau2212e6a2015-10-13 14:40:55 +0200492
493If the new process manages to bind correctly to all ports, then it sends either
494the SIGTERM (hard stop in case of "-st") or the SIGUSR1 (graceful stop in case
495of "-sf") to all processes to notify them that it is now in charge of operations
496and that the old processes will have to leave, either immediately or once they
497have finished their job.
498
499It is important to note that during this timeframe, there are two small windows
500of a few milliseconds each where it is possible that a few connection failures
501will be noticed during high loads. Typically observed failure rates are around
5021 failure during a reload operation every 10000 new connections per second,
503which means that a heavily loaded site running at 30000 new connections per
504second may see about 3 failed connection upon every reload. The two situations
505where this happens are :
506
507 - if the new process fails to bind due to the presence of the old process,
508 it will first have to go through the SIGTTOU+SIGTTIN sequence, which
509 typically lasts about one millisecond for a few tens of frontends, and
510 during which some ports will not be bound to the old process and not yet
511 bound to the new one. HAProxy works around this on systems that support the
512 SO_REUSEPORT socket options, as it allows the new process to bind without
513 first asking the old one to unbind. Most BSD systems have been supporting
514 this almost forever. Linux has been supporting this in version 2.0 and
515 dropped it around 2.2, but some patches were floating around by then. It
516 was reintroduced in kernel 3.9, so if you are observing a connection
Dan Lloyd8e48b872016-07-01 21:01:18 -0400517 failure rate above the one mentioned above, please ensure that your kernel
Willy Tarreau2212e6a2015-10-13 14:40:55 +0200518 is 3.9 or newer, or that relevant patches were backported to your kernel
519 (less likely).
520
521 - when the old processes close the listening ports, the kernel may not always
522 redistribute any pending connection that was remaining in the socket's
523 backlog. Under high loads, a SYN packet may happen just before the socket
524 is closed, and will lead to an RST packet being sent to the client. In some
525 critical environments where even one drop is not acceptable, these ones are
526 sometimes dealt with using firewall rules to block SYN packets during the
527 reload, forcing the client to retransmit. This is totally system-dependent,
528 as some systems might be able to visit other listening queues and avoid
529 this RST. A second case concerns the ACK from the client on a local socket
530 that was in SYN_RECV state just before the close. This ACK will lead to an
531 RST packet while the haproxy process is still not aware of it. This one is
Dan Lloyd8e48b872016-07-01 21:01:18 -0400532 harder to get rid of, though the firewall filtering rules mentioned above
Willy Tarreau2212e6a2015-10-13 14:40:55 +0200533 will work well if applied one second or so before restarting the process.
534
535For the vast majority of users, such drops will never ever happen since they
536don't have enough load to trigger the race conditions. And for most high traffic
537users, the failure rate is still fairly within the noise margin provided that at
538least SO_REUSEPORT is properly supported on their systems.
539
540
5415. File-descriptor limitations
542------------------------------
543
544In order to ensure that all incoming connections will successfully be served,
545HAProxy computes at load time the total number of file descriptors that will be
546needed during the process's life. A regular Unix process is generally granted
5471024 file descriptors by default, and a privileged process can raise this limit
548itself. This is one reason for starting HAProxy as root and letting it adjust
549the limit. The default limit of 1024 file descriptors roughly allow about 500
550concurrent connections to be processed. The computation is based on the global
551maxconn parameter which limits the total number of connections per process, the
552number of listeners, the number of servers which have a health check enabled,
553the agent checks, the peers, the loggers and possibly a few other technical
554requirements. A simple rough estimate of this number consists in simply
555doubling the maxconn value and adding a few tens to get the approximate number
556of file descriptors needed.
557
558Originally HAProxy did not know how to compute this value, and it was necessary
559to pass the value using the "ulimit-n" setting in the global section. This
560explains why even today a lot of configurations are seen with this setting
561present. Unfortunately it was often miscalculated resulting in connection
562failures when approaching maxconn instead of throttling incoming connection
563while waiting for the needed resources. For this reason it is important to
Dan Lloyd8e48b872016-07-01 21:01:18 -0400564remove any vestigial "ulimit-n" setting that can remain from very old versions.
Willy Tarreau2212e6a2015-10-13 14:40:55 +0200565
566Raising the number of file descriptors to accept even moderate loads is
567mandatory but comes with some OS-specific adjustments. First, the select()
568polling system is limited to 1024 file descriptors. In fact on Linux it used
569to be capable of handling more but since certain OS ship with excessively
570restrictive SELinux policies forbidding the use of select() with more than
5711024 file descriptors, HAProxy now refuses to start in this case in order to
572avoid any issue at run time. On all supported operating systems, poll() is
573available and will not suffer from this limitation. It is automatically picked
Dan Lloyd8e48b872016-07-01 21:01:18 -0400574so there is nothing to do to get a working configuration. But poll's becomes
Willy Tarreau2212e6a2015-10-13 14:40:55 +0200575very slow when the number of file descriptors increases. While HAProxy does its
576best to limit this performance impact (eg: via the use of the internal file
577descriptor cache and batched processing), a good rule of thumb is that using
578poll() with more than a thousand concurrent connections will use a lot of CPU.
579
580For Linux systems base on kernels 2.6 and above, the epoll() system call will
581be used. It's a much more scalable mechanism relying on callbacks in the kernel
582that guarantee a constant wake up time regardless of the number of registered
583monitored file descriptors. It is automatically used where detected, provided
584that HAProxy had been built for one of the Linux flavors. Its presence and
585support can be verified using "haproxy -vv".
586
587For BSD systems which support it, kqueue() is available as an alternative. It
588is much faster than poll() and even slightly faster than epoll() thanks to its
589batched handling of changes. At least FreeBSD and OpenBSD support it. Just like
590with Linux's epoll(), its support and availability are reported in the output
591of "haproxy -vv".
592
593Having a good poller is one thing, but it is mandatory that the process can
594reach the limits. When HAProxy starts, it immediately sets the new process's
595file descriptor limits and verifies if it succeeds. In case of failure, it
596reports it before forking so that the administrator can see the problem. As
597long as the process is started by as root, there should be no reason for this
598setting to fail. However, it can fail if the process is started by an
599unprivileged user. If there is a compelling reason for *not* starting haproxy
600as root (eg: started by end users, or by a per-application account), then the
601file descriptor limit can be raised by the system administrator for this
602specific user. The effectiveness of the setting can be verified by issuing
603"ulimit -n" from the user's command line. It should reflect the new limit.
604
605Warning: when an unprivileged user's limits are changed in this user's account,
606it is fairly common that these values are only considered when the user logs in
607and not at all in some scripts run at system boot time nor in crontabs. This is
608totally dependent on the operating system, keep in mind to check "ulimit -n"
609before starting haproxy when running this way. The general advice is never to
610start haproxy as an unprivileged user for production purposes. Another good
611reason is that it prevents haproxy from enabling some security protections.
612
613Once it is certain that the system will allow the haproxy process to use the
614requested number of file descriptors, two new system-specific limits may be
615encountered. The first one is the system-wide file descriptor limit, which is
616the total number of file descriptors opened on the system, covering all
617processes. When this limit is reached, accept() or socket() will typically
618return ENFILE. The second one is the per-process hard limit on the number of
619file descriptors, it prevents setrlimit() from being set higher. Both are very
620dependent on the operating system. On Linux, the system limit is set at boot
621based on the amount of memory. It can be changed with the "fs.file-max" sysctl.
622And the per-process hard limit is set to 1048576 by default, but it can be
623changed using the "fs.nr_open" sysctl.
624
625File descriptor limitations may be observed on a running process when they are
626set too low. The strace utility will report that accept() and socket() return
627"-1 EMFILE" when the process's limits have been reached. In this case, simply
628raising the "ulimit-n" value (or removing it) will solve the problem. If these
629system calls return "-1 ENFILE" then it means that the kernel's limits have
630been reached and that something must be done on a system-wide parameter. These
631trouble must absolutely be addressed, as they result in high CPU usage (when
632accept() fails) and failed connections that are generally visible to the user.
633One solution also consists in lowering the global maxconn value to enforce
634serialization, and possibly to disable HTTP keep-alive to force connections
635to be released and reused faster.
636
637
6386. Memory management
639--------------------
640
641HAProxy uses a simple and fast pool-based memory management. Since it relies on
642a small number of different object types, it's much more efficient to pick new
643objects from a pool which already contains objects of the appropriate size than
644to call malloc() for each different size. The pools are organized as a stack or
645LIFO, so that newly allocated objects are taken from recently released objects
646still hot in the CPU caches. Pools of similar sizes are merged together, in
647order to limit memory fragmentation.
648
649By default, since the focus is set on performance, each released object is put
650back into the pool it came from, and allocated objects are never freed since
651they are expected to be reused very soon.
652
653On the CLI, it is possible to check how memory is being used in pools thanks to
654the "show pools" command :
655
656 > show pools
657 Dumping pools usage. Use SIGQUIT to flush them.
Willy Tarreau0a93b642018-10-16 07:58:39 +0200658 - Pool cache_st (16 bytes) : 0 allocated (0 bytes), 0 used, 0 failures, 1 users, @0x9ccc40=03 [SHARED]
659 - Pool pipe (32 bytes) : 5 allocated (160 bytes), 5 used, 0 failures, 2 users, @0x9ccac0=00 [SHARED]
660 - Pool comp_state (48 bytes) : 3 allocated (144 bytes), 3 used, 0 failures, 5 users, @0x9cccc0=04 [SHARED]
661 - Pool filter (64 bytes) : 0 allocated (0 bytes), 0 used, 0 failures, 3 users, @0x9ccbc0=02 [SHARED]
662 - Pool vars (80 bytes) : 0 allocated (0 bytes), 0 used, 0 failures, 2 users, @0x9ccb40=01 [SHARED]
663 - Pool uniqueid (128 bytes) : 0 allocated (0 bytes), 0 used, 0 failures, 2 users, @0x9cd240=15 [SHARED]
664 - Pool task (144 bytes) : 55 allocated (7920 bytes), 55 used, 0 failures, 1 users, @0x9cd040=11 [SHARED]
665 - Pool session (160 bytes) : 1 allocated (160 bytes), 1 used, 0 failures, 1 users, @0x9cd140=13 [SHARED]
666 - Pool h2s (208 bytes) : 0 allocated (0 bytes), 0 used, 0 failures, 2 users, @0x9ccec0=08 [SHARED]
667 - Pool h2c (288 bytes) : 0 allocated (0 bytes), 0 used, 0 failures, 1 users, @0x9cce40=07 [SHARED]
668 - Pool spoe_ctx (304 bytes) : 0 allocated (0 bytes), 0 used, 0 failures, 2 users, @0x9ccf40=09 [SHARED]
669 - Pool connection (400 bytes) : 2 allocated (800 bytes), 2 used, 0 failures, 1 users, @0x9cd1c0=14 [SHARED]
670 - Pool hdr_idx (416 bytes) : 0 allocated (0 bytes), 0 used, 0 failures, 1 users, @0x9cd340=17 [SHARED]
671 - Pool dns_resolut (480 bytes) : 0 allocated (0 bytes), 0 used, 0 failures, 1 users, @0x9ccdc0=06 [SHARED]
672 - Pool dns_answer_ (576 bytes) : 0 allocated (0 bytes), 0 used, 0 failures, 1 users, @0x9ccd40=05 [SHARED]
673 - Pool stream (960 bytes) : 1 allocated (960 bytes), 1 used, 0 failures, 1 users, @0x9cd0c0=12 [SHARED]
674 - Pool requri (1024 bytes) : 0 allocated (0 bytes), 0 used, 0 failures, 1 users, @0x9cd2c0=16 [SHARED]
675 - Pool buffer (8030 bytes) : 3 allocated (24090 bytes), 2 used, 0 failures, 1 users, @0x9cd3c0=18 [SHARED]
676 - Pool trash (8062 bytes) : 1 allocated (8062 bytes), 1 used, 0 failures, 1 users, @0x9cd440=19
677 Total: 19 pools, 42296 bytes allocated, 34266 used.
Willy Tarreau2212e6a2015-10-13 14:40:55 +0200678
679The pool name is only indicative, it's the name of the first object type using
680this pool. The size in parenthesis is the object size for objects in this pool.
681Object sizes are always rounded up to the closest multiple of 16 bytes. The
682number of objects currently allocated and the equivalent number of bytes is
683reported so that it is easy to know which pool is responsible for the highest
684memory usage. The number of objects currently in use is reported as well in the
685"used" field. The difference between "allocated" and "used" corresponds to the
Willy Tarreau0a93b642018-10-16 07:58:39 +0200686objects that have been freed and are available for immediate use. The address
687at the end of the line is the pool's address, and the following number is the
688pool index when it exists, or is reported as -1 if no index was assigned.
Willy Tarreau2212e6a2015-10-13 14:40:55 +0200689
690It is possible to limit the amount of memory allocated per process using the
691"-m" command line option, followed by a number of megabytes. It covers all of
692the process's addressable space, so that includes memory used by some libraries
693as well as the stack, but it is a reliable limit when building a resource
694constrained system. It works the same way as "ulimit -v" on systems which have
695it, or "ulimit -d" for the other ones.
696
697If a memory allocation fails due to the memory limit being reached or because
698the system doesn't have any enough memory, then haproxy will first start to
699free all available objects from all pools before attempting to allocate memory
700again. This mechanism of releasing unused memory can be triggered by sending
701the signal SIGQUIT to the haproxy process. When doing so, the pools state prior
702to the flush will also be reported to stderr when the process runs in
703foreground.
704
705During a reload operation, the process switched to the graceful stop state also
706automatically performs some flushes after releasing any connection so that all
707possible memory is released to save it for the new process.
708
709
7107. CPU usage
711------------
712
713HAProxy normally spends most of its time in the system and a smaller part in
714userland. A finely tuned 3.5 GHz CPU can sustain a rate about 80000 end-to-end
715connection setups and closes per second at 100% CPU on a single core. When one
716core is saturated, typical figures are :
717 - 95% system, 5% user for long TCP connections or large HTTP objects
718 - 85% system and 15% user for short TCP connections or small HTTP objects in
719 close mode
720 - 70% system and 30% user for small HTTP objects in keep-alive mode
721
722The amount of rules processing and regular expressions will increase the user
723land part. The presence of firewall rules, connection tracking, complex routing
724tables in the system will instead increase the system part.
725
726On most systems, the CPU time observed during network transfers can be cut in 4
727parts :
728 - the interrupt part, which concerns all the processing performed upon I/O
729 receipt, before the target process is even known. Typically Rx packets are
730 accounted for in interrupt. On some systems such as Linux where interrupt
731 processing may be deferred to a dedicated thread, it can appear as softirq,
732 and the thread is called ksoftirqd/0 (for CPU 0). The CPU taking care of
733 this load is generally defined by the hardware settings, though in the case
734 of softirq it is often possible to remap the processing to another CPU.
735 This interrupt part will often be perceived as parasitic since it's not
736 associated with any process, but it actually is some processing being done
737 to prepare the work for the process.
738
739 - the system part, which concerns all the processing done using kernel code
740 called from userland. System calls are accounted as system for example. All
741 synchronously delivered Tx packets will be accounted for as system time. If
742 some packets have to be deferred due to queues filling up, they may then be
743 processed in interrupt context later (eg: upon receipt of an ACK opening a
744 TCP window).
745
746 - the user part, which exclusively runs application code in userland. HAProxy
747 runs exclusively in this part, though it makes heavy use of system calls.
748 Rules processing, regular expressions, compression, encryption all add to
749 the user portion of CPU consumption.
750
751 - the idle part, which is what the CPU does when there is nothing to do. For
752 example HAProxy waits for an incoming connection, or waits for some data to
753 leave, meaning the system is waiting for an ACK from the client to push
754 these data.
755
756In practice regarding HAProxy's activity, it is in general reasonably accurate
757(but totally inexact) to consider that interrupt/softirq are caused by Rx
758processing in kernel drivers, that user-land is caused by layer 7 processing
759in HAProxy, and that system time is caused by network processing on the Tx
760path.
761
762Since HAProxy runs around an event loop, it waits for new events using poll()
763(or any alternative) and processes all these events as fast as possible before
764going back to poll() waiting for new events. It measures the time spent waiting
765in poll() compared to the time spent doing processing events. The ratio of
766polling time vs total time is called the "idle" time, it's the amount of time
767spent waiting for something to happen. This ratio is reported in the stats page
768on the "idle" line, or "Idle_pct" on the CLI. When it's close to 100%, it means
769the load is extremely low. When it's close to 0%, it means that there is
770constantly some activity. While it cannot be very accurate on an overloaded
771system due to other processes possibly preempting the CPU from the haproxy
772process, it still provides a good estimate about how HAProxy considers it is
773working : if the load is low and the idle ratio is low as well, it may indicate
774that HAProxy has a lot of work to do, possibly due to very expensive rules that
775have to be processed. Conversely, if HAProxy indicates the idle is close to
776100% while things are slow, it means that it cannot do anything to speed things
777up because it is already waiting for incoming data to process. In the example
778below, haproxy is completely idle :
779
780 $ echo "show info" | socat - /var/run/haproxy.sock | grep ^Idle
781 Idle_pct: 100
782
783When the idle ratio starts to become very low, it is important to tune the
784system and place processes and interrupts correctly to save the most possible
785CPU resources for all tasks. If a firewall is present, it may be worth trying
786to disable it or to tune it to ensure it is not responsible for a large part
787of the performance limitation. It's worth noting that unloading a stateful
788firewall generally reduces both the amount of interrupt/softirq and of system
789usage since such firewalls act both on the Rx and the Tx paths. On Linux,
790unloading the nf_conntrack and ip_conntrack modules will show whether there is
791anything to gain. If so, then the module runs with default settings and you'll
792have to figure how to tune it for better performance. In general this consists
793in considerably increasing the hash table size. On FreeBSD, "pfctl -d" will
794disable the "pf" firewall and its stateful engine at the same time.
795
796If it is observed that a lot of time is spent in interrupt/softirq, it is
797important to ensure that they don't run on the same CPU. Most systems tend to
798pin the tasks on the CPU where they receive the network traffic because for
799certain workloads it improves things. But with heavily network-bound workloads
800it is the opposite as the haproxy process will have to fight against its kernel
801counterpart. Pinning haproxy to one CPU core and the interrupts to another one,
802all sharing the same L3 cache tends to sensibly increase network performance
803because in practice the amount of work for haproxy and the network stack are
804quite close, so they can almost fill an entire CPU each. On Linux this is done
805using taskset (for haproxy) or using cpu-map (from the haproxy config), and the
806interrupts are assigned under /proc/irq. Many network interfaces support
807multiple queues and multiple interrupts. In general it helps to spread them
808across a small number of CPU cores provided they all share the same L3 cache.
809Please always stop irq_balance which always does the worst possible thing on
810such workloads.
811
812For CPU-bound workloads consisting in a lot of SSL traffic or a lot of
813compression, it may be worth using multiple processes dedicated to certain
814tasks, though there is no universal rule here and experimentation will have to
815be performed.
816
817In order to increase the CPU capacity, it is possible to make HAProxy run as
818several processes, using the "nbproc" directive in the global section. There
819are some limitations though :
820 - health checks are run per process, so the target servers will get as many
821 checks as there are running processes ;
822 - maxconn values and queues are per-process so the correct value must be set
823 to avoid overloading the servers ;
824 - outgoing connections should avoid using port ranges to avoid conflicts
825 - stick-tables are per process and are not shared between processes ;
826 - each peers section may only run on a single process at a time ;
827 - the CLI operations will only act on a single process at a time.
828
829With this in mind, it appears that the easiest setup often consists in having
830one first layer running on multiple processes and in charge for the heavy
831processing, passing the traffic to a second layer running in a single process.
832This mechanism is suited to SSL and compression which are the two CPU-heavy
833features. Instances can easily be chained over UNIX sockets (which are cheaper
fengpeiyuancc123c62016-01-15 16:40:53 +0800834than TCP sockets and which do not waste ports), and the proxy protocol which is
Willy Tarreau2212e6a2015-10-13 14:40:55 +0200835useful to pass client information to the next stage. When doing so, it is
836generally a good idea to bind all the single-process tasks to process number 1
837and extra tasks to next processes, as this will make it easier to generate
838similar configurations for different machines.
839
840On Linux versions 3.9 and above, running HAProxy in multi-process mode is much
841more efficient when each process uses a distinct listening socket on the same
842IP:port ; this will make the kernel evenly distribute the load across all
843processes instead of waking them all up. Please check the "process" option of
844the "bind" keyword lines in the configuration manual for more information.
845
846
8478. Logging
848----------
849
850For logging, HAProxy always relies on a syslog server since it does not perform
851any file-system access. The standard way of using it is to send logs over UDP
852to the log server (by default on port 514). Very commonly this is configured to
853127.0.0.1 where the local syslog daemon is running, but it's also used over the
854network to log to a central server. The central server provides additional
855benefits especially in active-active scenarios where it is desirable to keep
856the logs merged in arrival order. HAProxy may also make use of a UNIX socket to
857send its logs to the local syslog daemon, but it is not recommended at all,
858because if the syslog server is restarted while haproxy runs, the socket will
859be replaced and new logs will be lost. Since HAProxy will be isolated inside a
860chroot jail, it will not have the ability to reconnect to the new socket. It
861has also been observed in field that the log buffers in use on UNIX sockets are
862very small and lead to lost messages even at very light loads. But this can be
863fine for testing however.
864
865It is recommended to add the following directive to the "global" section to
866make HAProxy log to the local daemon using facility "local0" :
867
868 log 127.0.0.1:514 local0
869
870and then to add the following one to each "defaults" section or to each frontend
871and backend section :
872
873 log global
874
875This way, all logs will be centralized through the global definition of where
876the log server is.
877
878Some syslog daemons do not listen to UDP traffic by default, so depending on
879the daemon being used, the syntax to enable this will vary :
880
881 - on sysklogd, you need to pass argument "-r" on the daemon's command line
882 so that it listens to a UDP socket for "remote" logs ; note that there is
883 no way to limit it to address 127.0.0.1 so it will also receive logs from
884 remote systems ;
885
886 - on rsyslogd, the following lines must be added to the configuration file :
887
888 $ModLoad imudp
889 $UDPServerAddress *
890 $UDPServerRun 514
891
892 - on syslog-ng, a new source can be created the following way, it then needs
893 to be added as a valid source in one of the "log" directives :
894
895 source s_udp {
896 udp(ip(127.0.0.1) port(514));
897 };
898
899Please consult your syslog daemon's manual for more information. If no logs are
900seen in the system's log files, please consider the following tests :
901
902 - restart haproxy. Each frontend and backend logs one line indicating it's
903 starting. If these logs are received, it means logs are working.
904
905 - run "strace -tt -s100 -etrace=sendmsg -p <haproxy's pid>" and perform some
906 activity that you expect to be logged. You should see the log messages
907 being sent using sendmsg() there. If they don't appear, restart using
908 strace on top of haproxy. If you still see no logs, it definitely means
909 that something is wrong in your configuration.
910
911 - run tcpdump to watch for port 514, for example on the loopback interface if
912 the traffic is being sent locally : "tcpdump -As0 -ni lo port 514". If the
913 packets are seen there, it's the proof they're sent then the syslogd daemon
914 needs to be troubleshooted.
915
916While traffic logs are sent from the frontends (where the incoming connections
917are accepted), backends also need to be able to send logs in order to report a
918server state change consecutive to a health check. Please consult HAProxy's
919configuration manual for more information regarding all possible log settings.
920
Dan Lloyd8e48b872016-07-01 21:01:18 -0400921It is convenient to chose a facility that is not used by other daemons. HAProxy
Willy Tarreau2212e6a2015-10-13 14:40:55 +0200922examples often suggest "local0" for traffic logs and "local1" for admin logs
923because they're never seen in field. A single facility would be enough as well.
924Having separate logs is convenient for log analysis, but it's also important to
925remember that logs may sometimes convey confidential information, and as such
Dan Lloyd8e48b872016-07-01 21:01:18 -0400926they must not be mixed with other logs that may accidentally be handed out to
Willy Tarreau2212e6a2015-10-13 14:40:55 +0200927unauthorized people.
928
929For in-field troubleshooting without impacting the server's capacity too much,
930it is recommended to make use of the "halog" utility provided with HAProxy.
931This is sort of a grep-like utility designed to process HAProxy log files at
932a very fast data rate. Typical figures range between 1 and 2 GB of logs per
933second. It is capable of extracting only certain logs (eg: search for some
934classes of HTTP status codes, connection termination status, search by response
935time ranges, look for errors only), count lines, limit the output to a number
936of lines, and perform some more advanced statistics such as sorting servers
937by response time or error counts, sorting URLs by time or count, sorting client
938addresses by access count, and so on. It is pretty convenient to quickly spot
939anomalies such as a bot looping on the site, and block them.
940
941
9429. Statistics and monitoring
943----------------------------
944
Willy Tarreau44aed902015-10-13 14:45:29 +0200945It is possible to query HAProxy about its status. The most commonly used
946mechanism is the HTTP statistics page. This page also exposes an alternative
947CSV output format for monitoring tools. The same format is provided on the
948Unix socket.
949
Amaury Denoyelle072f97e2020-10-05 11:49:37 +0200950Statistics are regroup in categories labelled as domains, corresponding to the
Ilya Shipitsin2272d8a2020-12-21 01:22:40 +0500951multiple components of HAProxy. There are two domains available: proxy and dns.
Amaury Denoyellefbd0bc92020-10-05 11:49:46 +0200952If not specified, the proxy domain is selected. Note that only the proxy
953statistics are printed on the HTTP page.
Willy Tarreau44aed902015-10-13 14:45:29 +0200954
9559.1. CSV format
956---------------
957
958The statistics may be consulted either from the unix socket or from the HTTP
959page. Both means provide a CSV format whose fields follow. The first line
960begins with a sharp ('#') and has one word per comma-delimited field which
961represents the title of the column. All other lines starting at the second one
962use a classical CSV format using a comma as the delimiter, and the double quote
963('"') as an optional text delimiter, but only if the enclosed text is ambiguous
964(if it contains a quote or a comma). The double-quote character ('"') in the
965text is doubled ('""'), which is the format that most tools recognize. Please
966do not insert any column before these ones in order not to break tools which
967use hard-coded column positions.
968
Amaury Denoyelle50660a82020-10-05 11:49:39 +0200969For proxy statistics, after each field name, the types which may have a value
970for that field are specified in brackets. The types are L (Listeners), F
971(Frontends), B (Backends), and S (Servers). There is a fixed set of static
972fields that are always available in the same order. A column containing the
973character '-' delimits the end of the static fields, after which presence or
974order of the fields are not guaranteed.
Willy Tarreau44aed902015-10-13 14:45:29 +0200975
Amaury Denoyelle50660a82020-10-05 11:49:39 +0200976Here is the list of static fields using the proxy statistics domain:
Willy Tarreau44aed902015-10-13 14:45:29 +0200977 0. pxname [LFBS]: proxy name
978 1. svname [LFBS]: service name (FRONTEND for frontend, BACKEND for backend,
979 any name for server/listener)
980 2. qcur [..BS]: current queued requests. For the backend this reports the
981 number queued without a server assigned.
982 3. qmax [..BS]: max value of qcur
983 4. scur [LFBS]: current sessions
984 5. smax [LFBS]: max sessions
985 6. slim [LFBS]: configured session limit
Willy Tarreauc73810f2016-01-11 13:52:04 +0100986 7. stot [LFBS]: cumulative number of sessions
Willy Tarreau44aed902015-10-13 14:45:29 +0200987 8. bin [LFBS]: bytes in
988 9. bout [LFBS]: bytes out
989 10. dreq [LFB.]: requests denied because of security concerns.
990 - For tcp this is because of a matched tcp-request content rule.
991 - For http this is because of a matched http-request or tarpit rule.
992 11. dresp [LFBS]: responses denied because of security concerns.
993 - For http this is because of a matched http-request rule, or
994 "option checkcache".
995 12. ereq [LF..]: request errors. Some of the possible causes are:
996 - early termination from the client, before the request has been sent.
997 - read error from the client
998 - client timeout
999 - client closed connection
1000 - various bad requests from the client.
1001 - request was tarpitted.
1002 13. econ [..BS]: number of requests that encountered an error trying to
1003 connect to a backend server. The backend stat is the sum of the stat
1004 for all servers of that backend, plus any connection errors not
1005 associated with a particular server (such as the backend having no
1006 active servers).
1007 14. eresp [..BS]: response errors. srv_abrt will be counted here also.
1008 Some other errors are:
1009 - write error on the client socket (won't be counted for the server stat)
1010 - failure applying filters to the response.
1011 15. wretr [..BS]: number of times a connection to a server was retried.
1012 16. wredis [..BS]: number of times a request was redispatched to another
1013 server. The server value counts the number of times that server was
1014 switched away from.
Willy Tarreaub96dd282016-11-09 14:45:51 +01001015 17. status [LFBS]: status (UP/DOWN/NOLB/MAINT/MAINT(via)/MAINT(resolution)...)
Willy Tarreaubd715102020-10-23 22:44:30 +02001016 18. weight [..BS]: total effective weight (backend), effective weight (server)
Willy Tarreau44aed902015-10-13 14:45:29 +02001017 19. act [..BS]: number of active servers (backend), server is active (server)
1018 20. bck [..BS]: number of backup servers (backend), server is backup (server)
1019 21. chkfail [...S]: number of failed checks. (Only counts checks failed when
1020 the server is up.)
1021 22. chkdown [..BS]: number of UP->DOWN transitions. The backend counter counts
1022 transitions to the whole backend being down, rather than the sum of the
1023 counters for each server.
1024 23. lastchg [..BS]: number of seconds since the last UP<->DOWN transition
1025 24. downtime [..BS]: total downtime (in seconds). The value for the backend
1026 is the downtime for the whole backend, not the sum of the server downtime.
1027 25. qlimit [...S]: configured maxqueue for the server, or nothing in the
1028 value is 0 (default, meaning no limit)
1029 26. pid [LFBS]: process id (0 for first instance, 1 for second, ...)
1030 27. iid [LFBS]: unique proxy id
1031 28. sid [L..S]: server id (unique inside a proxy)
1032 29. throttle [...S]: current throttle percentage for the server, when
1033 slowstart is active, or no value if not in slowstart.
1034 30. lbtot [..BS]: total number of times a server was selected, either for new
1035 sessions, or when re-dispatching. The server counter is the number
1036 of times that server was selected.
1037 31. tracked [...S]: id of proxy/server if tracking is enabled.
1038 32. type [LFBS]: (0=frontend, 1=backend, 2=server, 3=socket/listener)
1039 33. rate [.FBS]: number of sessions per second over last elapsed second
1040 34. rate_lim [.F..]: configured limit on new sessions per second
1041 35. rate_max [.FBS]: max number of new sessions per second
1042 36. check_status [...S]: status of last health check, one of:
1043 UNK -> unknown
1044 INI -> initializing
1045 SOCKERR -> socket error
1046 L4OK -> check passed on layer 4, no upper layers testing enabled
1047 L4TOUT -> layer 1-4 timeout
1048 L4CON -> layer 1-4 connection problem, for example
1049 "Connection refused" (tcp rst) or "No route to host" (icmp)
1050 L6OK -> check passed on layer 6
1051 L6TOUT -> layer 6 (SSL) timeout
1052 L6RSP -> layer 6 invalid response - protocol error
1053 L7OK -> check passed on layer 7
1054 L7OKC -> check conditionally passed on layer 7, for example 404 with
1055 disable-on-404
1056 L7TOUT -> layer 7 (HTTP/SMTP) timeout
1057 L7RSP -> layer 7 invalid response - protocol error
1058 L7STS -> layer 7 response error, for example HTTP 5xx
Daniel Schnellerb6c8b0d2017-09-01 19:13:55 +02001059 Notice: If a check is currently running, the last known status will be
1060 reported, prefixed with "* ". e. g. "* L7OK".
Willy Tarreau44aed902015-10-13 14:45:29 +02001061 37. check_code [...S]: layer5-7 code, if available
1062 38. check_duration [...S]: time in ms took to finish last health check
1063 39. hrsp_1xx [.FBS]: http responses with 1xx code
1064 40. hrsp_2xx [.FBS]: http responses with 2xx code
1065 41. hrsp_3xx [.FBS]: http responses with 3xx code
1066 42. hrsp_4xx [.FBS]: http responses with 4xx code
1067 43. hrsp_5xx [.FBS]: http responses with 5xx code
1068 44. hrsp_other [.FBS]: http responses with other codes (protocol error)
1069 45. hanafail [...S]: failed health checks details
1070 46. req_rate [.F..]: HTTP requests per second over last elapsed second
1071 47. req_rate_max [.F..]: max number of HTTP requests per second observed
Willy Tarreaufb981bd2016-12-12 14:31:46 +01001072 48. req_tot [.FB.]: total number of HTTP requests received
Willy Tarreau44aed902015-10-13 14:45:29 +02001073 49. cli_abrt [..BS]: number of data transfers aborted by the client
1074 50. srv_abrt [..BS]: number of data transfers aborted by the server
1075 (inc. in eresp)
1076 51. comp_in [.FB.]: number of HTTP response bytes fed to the compressor
1077 52. comp_out [.FB.]: number of HTTP response bytes emitted by the compressor
1078 53. comp_byp [.FB.]: number of bytes that bypassed the HTTP compressor
1079 (CPU/BW limit)
1080 54. comp_rsp [.FB.]: number of HTTP responses that were compressed
1081 55. lastsess [..BS]: number of seconds since last session assigned to
1082 server/backend
1083 56. last_chk [...S]: last health check contents or textual error
1084 57. last_agt [...S]: last agent check contents or textual error
1085 58. qtime [..BS]: the average queue time in ms over the 1024 last requests
1086 59. ctime [..BS]: the average connect time in ms over the 1024 last requests
1087 60. rtime [..BS]: the average response time in ms over the 1024 last requests
1088 (0 for TCP)
1089 61. ttime [..BS]: the average total session time in ms over the 1024 last
1090 requests
Willy Tarreau7f618842016-01-08 11:40:03 +01001091 62. agent_status [...S]: status of last agent check, one of:
1092 UNK -> unknown
1093 INI -> initializing
1094 SOCKERR -> socket error
1095 L4OK -> check passed on layer 4, no upper layers testing enabled
1096 L4TOUT -> layer 1-4 timeout
1097 L4CON -> layer 1-4 connection problem, for example
1098 "Connection refused" (tcp rst) or "No route to host" (icmp)
1099 L7OK -> agent reported "up"
1100 L7STS -> agent reported "fail", "stop", or "down"
1101 63. agent_code [...S]: numeric code reported by agent if any (unused for now)
1102 64. agent_duration [...S]: time in ms taken to finish last check
Willy Tarreaudd7354b2016-01-08 13:47:26 +01001103 65. check_desc [...S]: short human-readable description of check_status
1104 66. agent_desc [...S]: short human-readable description of agent_status
Willy Tarreau3141f592016-01-08 14:25:28 +01001105 67. check_rise [...S]: server's "rise" parameter used by checks
1106 68. check_fall [...S]: server's "fall" parameter used by checks
1107 69. check_health [...S]: server's health check value between 0 and rise+fall-1
1108 70. agent_rise [...S]: agent's "rise" parameter, normally 1
1109 71. agent_fall [...S]: agent's "fall" parameter, normally 1
1110 72. agent_health [...S]: agent's health parameter, between 0 and rise+fall-1
Willy Tarreaua6f5a732016-01-08 16:59:56 +01001111 73. addr [L..S]: address:port or "unix". IPv6 has brackets around the address.
Willy Tarreaue4847c62016-01-08 15:43:54 +01001112 74: cookie [..BS]: server's cookie value or backend's cookie name
Willy Tarreauf8211df2016-01-11 14:09:38 +01001113 75: mode [LFBS]: proxy mode (tcp, http, health, unknown)
Willy Tarreauf1516d92016-01-11 14:48:36 +01001114 76: algo [..B.]: load balancing algorithm
Willy Tarreauc73810f2016-01-11 13:52:04 +01001115 77: conn_rate [.F..]: number of connections over the last elapsed second
1116 78: conn_rate_max [.F..]: highest known conn_rate
1117 79: conn_tot [.F..]: cumulative number of connections
Willy Tarreau5b9bdff2016-01-11 14:40:47 +01001118 80: intercepted [.FB.]: cum. number of intercepted requests (monitor, stats)
Willy Tarreau8a90b8e2016-10-21 18:15:32 +02001119 81: dcon [LF..]: requests denied by "tcp-request connection" rules
Willy Tarreaua5bc36b2016-10-21 18:16:27 +02001120 82: dses [LF..]: requests denied by "tcp-request session" rules
Willy Tarreauea96a822018-05-28 15:15:43 +02001121 83: wrew [LFBS]: cumulative number of failed header rewriting warnings
Jérôme Magnin708eb882019-07-17 09:24:46 +02001122 84: connect [..BS]: cumulative number of connection establishment attempts
1123 85: reuse [..BS]: cumulative number of connection reuses
Willy Tarreau72974292019-11-08 07:29:34 +01001124 86: cache_lookups [.FB.]: cumulative number of cache lookups
Jérôme Magnin34ebb5c2019-07-17 14:04:40 +02001125 87: cache_hits [.FB.]: cumulative number of cache hits
Christopher Faulet2ac25742019-11-08 15:27:27 +01001126 88: srv_icur [...S]: current number of idle connections available for reuse
1127 89: src_ilim [...S]: limit on the number of available idle connections
1128 90. qtime_max [..BS]: the maximum observed queue time in ms
1129 91. ctime_max [..BS]: the maximum observed connect time in ms
1130 92. rtime_max [..BS]: the maximum observed response time in ms (0 for TCP)
1131 93. ttime_max [..BS]: the maximum observed total session time in ms
Christopher Faulet0159ee42019-12-16 14:40:39 +01001132 94. eint [LFBS]: cumulative number of internal errors
Pierre Cheynier08eb7182020-10-08 16:37:14 +02001133 95. idle_conn_cur [...S]: current number of unsafe idle connections
1134 96. safe_conn_cur [...S]: current number of safe idle connections
1135 97. used_conn_cur [...S]: current number of connections in use
1136 98. need_conn_est [...S]: estimated needed number of connections
Willy Tarreaubd715102020-10-23 22:44:30 +02001137 99. uweight [..BS]: total user weight (backend), server user weight (server)
Willy Tarreau44aed902015-10-13 14:45:29 +02001138
Amaury Denoyelle50660a82020-10-05 11:49:39 +02001139For all other statistics domains, the presence or the order of the fields are
1140not guaranteed. In this case, the header line should always be used to parse
1141the CSV data.
Willy Tarreau44aed902015-10-13 14:45:29 +02001142
Phil Schererb931f962020-12-02 19:36:08 +000011439.2. Typed output format
Willy Tarreau5d8b9792016-03-11 11:09:34 +01001144------------------------
1145
1146Both "show info" and "show stat" support a mode where each output value comes
1147with its type and sufficient information to know how the value is supposed to
1148be aggregated between processes and how it evolves.
1149
1150In all cases, the output consists in having a single value per line with all
1151the information split into fields delimited by colons (':').
1152
1153The first column designates the object or metric being dumped. Its format is
1154specific to the command producing this output and will not be described in this
1155section. Usually it will consist in a series of identifiers and field names.
1156
1157The second column contains 3 characters respectively indicating the origin, the
1158nature and the scope of the value being reported. The first character (the
1159origin) indicates where the value was extracted from. Possible characters are :
1160
1161 M The value is a metric. It is valid at one instant any may change depending
1162 on its nature .
1163
1164 S The value is a status. It represents a discrete value which by definition
1165 cannot be aggregated. It may be the status of a server ("UP" or "DOWN"),
1166 the PID of the process, etc.
1167
1168 K The value is a sorting key. It represents an identifier which may be used
1169 to group some values together because it is unique among its class. All
1170 internal identifiers are keys. Some names can be listed as keys if they
1171 are unique (eg: a frontend name is unique). In general keys come from the
Dan Lloyd8e48b872016-07-01 21:01:18 -04001172 configuration, even though some of them may automatically be assigned. For
Willy Tarreau5d8b9792016-03-11 11:09:34 +01001173 most purposes keys may be considered as equivalent to configuration.
1174
1175 C The value comes from the configuration. Certain configuration values make
1176 sense on the output, for example a concurrent connection limit or a cookie
1177 name. By definition these values are the same in all processes started
1178 from the same configuration file.
1179
1180 P The value comes from the product itself. There are very few such values,
1181 most common use is to report the product name, version and release date.
1182 These elements are also the same between all processes.
1183
1184The second character (the nature) indicates the nature of the information
1185carried by the field in order to let an aggregator decide on what operation to
1186use to aggregate multiple values. Possible characters are :
1187
1188 A The value represents an age since a last event. This is a bit different
1189 from the duration in that an age is automatically computed based on the
1190 current date. A typical example is how long ago did the last session
1191 happen on a server. Ages are generally aggregated by taking the minimum
1192 value and do not need to be stored.
1193
1194 a The value represents an already averaged value. The average response times
1195 and server weights are of this nature. Averages can typically be averaged
1196 between processes.
1197
1198 C The value represents a cumulative counter. Such measures perpetually
1199 increase until they wrap around. Some monitoring protocols need to tell
1200 the difference between a counter and a gauge to report a different type.
1201 In general counters may simply be summed since they represent events or
1202 volumes. Examples of metrics of this nature are connection counts or byte
1203 counts.
1204
1205 D The value represents a duration for a status. There are a few usages of
1206 this, most of them include the time taken by the last health check and
1207 the time a server has spent down. Durations are generally not summed,
1208 most of the time the maximum will be retained to compute an SLA.
1209
1210 G The value represents a gauge. It's a measure at one instant. The memory
1211 usage or the current number of active connections are of this nature.
1212 Metrics of this type are typically summed during aggregation.
1213
1214 L The value represents a limit (generally a configured one). By nature,
1215 limits are harder to aggregate since they are specific to the point where
1216 they were retrieved. In certain situations they may be summed or be kept
1217 separate.
1218
1219 M The value represents a maximum. In general it will apply to a gauge and
1220 keep the highest known value. An example of such a metric could be the
1221 maximum amount of concurrent connections that was encountered in the
1222 product's life time. To correctly aggregate maxima, you are supposed to
1223 output a range going from the maximum of all maxima and the sum of all
1224 of them. There is indeed no way to know if they were encountered
1225 simultaneously or not.
1226
1227 m The value represents a minimum. In general it will apply to a gauge and
1228 keep the lowest known value. An example of such a metric could be the
1229 minimum amount of free memory pools that was encountered in the product's
1230 life time. To correctly aggregate minima, you are supposed to output a
1231 range going from the minimum of all minima and the sum of all of them.
1232 There is indeed no way to know if they were encountered simultaneously
1233 or not.
1234
1235 N The value represents a name, so it is a string. It is used to report
1236 proxy names, server names and cookie names. Names have configuration or
1237 keys as their origin and are supposed to be the same among all processes.
1238
1239 O The value represents a free text output. Outputs from various commands,
1240 returns from health checks, node descriptions are of such nature.
1241
1242 R The value represents an event rate. It's a measure at one instant. It is
1243 quite similar to a gauge except that the recipient knows that this measure
1244 moves slowly and may decide not to keep all values. An example of such a
1245 metric is the measured amount of connections per second. Metrics of this
1246 type are typically summed during aggregation.
1247
1248 T The value represents a date or time. A field emitting the current date
1249 would be of this type. The method to aggregate such information is left
1250 as an implementation choice. For now no field uses this type.
1251
1252The third character (the scope) indicates what extent the value reflects. Some
1253elements may be per process while others may be per configuration or per system.
1254The distinction is important to know whether or not a single value should be
1255kept during aggregation or if values have to be aggregated. The following
1256characters are currently supported :
1257
1258 C The value is valid for a whole cluster of nodes, which is the set of nodes
1259 communicating over the peers protocol. An example could be the amount of
1260 entries present in a stick table that is replicated with other peers. At
1261 the moment no metric use this scope.
1262
1263 P The value is valid only for the process reporting it. Most metrics use
1264 this scope.
1265
1266 S The value is valid for the whole service, which is the set of processes
1267 started together from the same configuration file. All metrics originating
1268 from the configuration use this scope. Some other metrics may use it as
1269 well for some shared resources (eg: shared SSL cache statistics).
1270
1271 s The value is valid for the whole system, such as the system's hostname,
1272 current date or resource usage. At the moment this scope is not used by
1273 any metric.
1274
1275Consumers of these information will generally have enough of these 3 characters
1276to determine how to accurately report aggregated information across multiple
1277processes.
1278
1279After this column, the third column indicates the type of the field, among "s32"
1280(signed 32-bit integer), "s64" (signed 64-bit integer), "u32" (unsigned 32-bit
1281integer), "u64" (unsigned 64-bit integer), "str" (string). It is important to
1282know the type before parsing the value in order to properly read it. For example
1283a string containing only digits is still a string an not an integer (eg: an
1284error code extracted by a check).
1285
1286Then the fourth column is the value itself, encoded according to its type.
1287Strings are dumped as-is immediately after the colon without any leading space.
1288If a string contains a colon, it will appear normally. This means that the
1289output should not be exclusively split around colons or some check outputs
1290or server addresses might be truncated.
1291
1292
12939.3. Unix Socket commands
Willy Tarreau44aed902015-10-13 14:45:29 +02001294-------------------------
1295
1296The stats socket is not enabled by default. In order to enable it, it is
1297necessary to add one line in the global section of the haproxy configuration.
1298A second line is recommended to set a larger timeout, always appreciated when
1299issuing commands by hand :
1300
1301 global
1302 stats socket /var/run/haproxy.sock mode 600 level admin
1303 stats timeout 2m
1304
1305It is also possible to add multiple instances of the stats socket by repeating
1306the line, and make them listen to a TCP port instead of a UNIX socket. This is
1307never done by default because this is dangerous, but can be handy in some
1308situations :
1309
1310 global
1311 stats socket /var/run/haproxy.sock mode 600 level admin
1312 stats socket ipv4@192.168.0.1:9999 level admin
1313 stats timeout 2m
1314
1315To access the socket, an external utility such as "socat" is required. Socat is
1316a swiss-army knife to connect anything to anything. We use it to connect
1317terminals to the socket, or a couple of stdin/stdout pipes to it for scripts.
1318The two main syntaxes we'll use are the following :
1319
1320 # socat /var/run/haproxy.sock stdio
1321 # socat /var/run/haproxy.sock readline
1322
1323The first one is used with scripts. It is possible to send the output of a
1324script to haproxy, and pass haproxy's output to another script. That's useful
1325for retrieving counters or attack traces for example.
1326
1327The second one is only useful for issuing commands by hand. It has the benefit
1328that the terminal is handled by the readline library which supports line
1329editing and history, which is very convenient when issuing repeated commands
1330(eg: watch a counter).
1331
1332The socket supports two operation modes :
1333 - interactive
1334 - non-interactive
1335
1336The non-interactive mode is the default when socat connects to the socket. In
1337this mode, a single line may be sent. It is processed as a whole, responses are
1338sent back, and the connection closes after the end of the response. This is the
1339mode that scripts and monitoring tools use. It is possible to send multiple
1340commands in this mode, they need to be delimited by a semi-colon (';'). For
1341example :
1342
1343 # echo "show info;show stat;show table" | socat /var/run/haproxy stdio
1344
Dragan Dosena1c35ab2016-11-24 11:33:12 +01001345If a command needs to use a semi-colon or a backslash (eg: in a value), it
Joseph Herlant71b4b152018-11-13 16:55:16 -08001346must be preceded by a backslash ('\').
Chad Lavoiee3f50312016-05-26 16:42:25 -04001347
Willy Tarreau44aed902015-10-13 14:45:29 +02001348The interactive mode displays a prompt ('>') and waits for commands to be
1349entered on the line, then processes them, and displays the prompt again to wait
1350for a new command. This mode is entered via the "prompt" command which must be
1351sent on the first line in non-interactive mode. The mode is a flip switch, if
1352"prompt" is sent in interactive mode, it is disabled and the connection closes
1353after processing the last command of the same line.
1354
1355For this reason, when debugging by hand, it's quite common to start with the
1356"prompt" command :
1357
1358 # socat /var/run/haproxy readline
1359 prompt
1360 > show info
1361 ...
1362 >
1363
1364Since multiple commands may be issued at once, haproxy uses the empty line as a
1365delimiter to mark an end of output for each command, and takes care of ensuring
1366that no command can emit an empty line on output. A script can thus easily
1367parse the output even when multiple commands were pipelined on a single line.
1368
Aurélien Nephtaliabbf6072018-04-18 13:26:46 +02001369Some commands may take an optional payload. To add one to a command, the first
1370line needs to end with the "<<\n" pattern. The next lines will be treated as
1371the payload and can contain as many lines as needed. To validate a command with
1372a payload, it needs to end with an empty line.
1373
1374Limitations do exist: the length of the whole buffer passed to the CLI must
1375not be greater than tune.bfsize and the pattern "<<" must not be glued to the
1376last word of the line.
1377
1378When entering a paylod while in interactive mode, the prompt will change from
1379"> " to "+ ".
1380
Willy Tarreau44aed902015-10-13 14:45:29 +02001381It is important to understand that when multiple haproxy processes are started
1382on the same sockets, any process may pick up the request and will output its
1383own stats.
1384
1385The list of commands currently supported on the stats socket is provided below.
1386If an unknown command is sent, haproxy displays the usage message which reminds
1387all supported commands. Some commands support a more complex syntax, generally
1388it will explain what part of the command is invalid when this happens.
1389
Olivier Doucetd8703e82017-08-31 11:05:10 +02001390Some commands require a higher level of privilege to work. If you do not have
1391enough privilege, you will get an error "Permission denied". Please check
1392the "level" option of the "bind" keyword lines in the configuration manual
1393for more information.
1394
William Lallemand6ab08b32019-11-29 16:48:43 +01001395abort ssl cert <filename>
1396 Abort and destroy a temporary SSL certificate update transaction.
1397
1398 See also "set ssl cert" and "commit ssl cert".
1399
Willy Tarreaubb51c442021-04-30 15:23:36 +02001400add acl [@<ver>] <acl> <pattern>
Willy Tarreau44aed902015-10-13 14:45:29 +02001401 Add an entry into the acl <acl>. <acl> is the #<id> or the <file> returned by
Willy Tarreaubb51c442021-04-30 15:23:36 +02001402 "show acl". This command does not verify if the entry already exists. Entries
1403 are added to the current version of the ACL, unless a specific version is
1404 specified with "@<ver>". This version number must have preliminary been
1405 allocated by "prepare acl", and it will be comprised between the versions
1406 reported in "curr_ver" and "next_ver" on the output of "show acl". Entries
1407 added with a specific version number will not match until a "commit acl"
1408 operation is performed on them. They may however be consulted using the
1409 "show acl @<ver>" command, and cleared using a "clear acl @<ver>" command.
1410 This command cannot be used if the reference <acl> is a file also used with
1411 a map. In this case, the "add map" command must be used instead.
Willy Tarreau44aed902015-10-13 14:45:29 +02001412
Willy Tarreaubb51c442021-04-30 15:23:36 +02001413add map [@<ver>] <map> <key> <value>
1414add map [@<ver>] <map> <payload>
Willy Tarreau44aed902015-10-13 14:45:29 +02001415 Add an entry into the map <map> to associate the value <value> to the key
1416 <key>. This command does not verify if the entry already exists. It is
Willy Tarreaubb51c442021-04-30 15:23:36 +02001417 mainly used to fill a map after a "clear" or "prepare" operation. Entries
1418 are added to the current version of the ACL, unless a specific version is
1419 specified with "@<ver>". This version number must have preliminary been
1420 allocated by "prepare acl", and it will be comprised between the versions
1421 reported in "curr_ver" and "next_ver" on the output of "show acl". Entries
1422 added with a specific version number will not match until a "commit map"
1423 operation is performed on them. They may however be consulted using the
1424 "show map @<ver>" command, and cleared using a "clear acl @<ver>" command.
1425 If the designated map is also used as an ACL, the ACL will only match the
1426 <key> part and will ignore the <value> part. Using the payload syntax it is
1427 possible to add multiple key/value pairs by entering them on separate lines.
1428 On each new line, the first word is the key and the rest of the line is
1429 considered to be the value which can even contains spaces.
Aurélien Nephtali25650ce2018-04-18 14:04:47 +02001430
1431 Example:
1432
1433 # socat /tmp/sock1 -
1434 prompt
1435
1436 > add map #-1 <<
1437 + key1 value1
1438 + key2 value2 with spaces
1439 + key3 value3 also with spaces
1440 + key4 value4
1441
1442 >
Willy Tarreau44aed902015-10-13 14:45:29 +02001443
Amaury Denoyellef99f77a2021-03-08 17:13:32 +01001444add server <backend>/<server> [args]*
1445 Instantiate a new server attached to the backend <backend>. Only supported on
1446 a CLI connection running in experimental mode (see "experimental-mode on").
1447 This method is still in development and may change in the future.
1448
1449 The <server> name must not be already used in the backend. A special
Amaury Denoyelleeafd7012021-04-29 14:59:42 +02001450 restriction is put on the backend which must used a dynamic load-balancing
1451 algorithm. A subset of keywords from the server config file statement can be
1452 used to configure the server behavior. Also note that no settings will be
1453 reused from an hypothetical 'default-server' statement in the same backend.
Amaury Denoyellefc465a52021-03-09 17:36:23 +01001454
1455 Here is the list of the currently supported keywords :
1456
1457 - backup
1458 - disabled
1459 - enabled
1460 - id
1461 - maxconn
1462 - maxqueue
1463 - minconn
1464 - pool-low-conn
1465 - pool-max-conn
1466 - pool-purge-delay
Amaury Denoyelle30467232021-03-12 18:03:27 +01001467 - proto
Amaury Denoyellefc465a52021-03-09 17:36:23 +01001468 - proxy-v2-options
1469 - send-proxy
1470 - send-proxy-v2
1471 - source
1472 - tfo
1473 - usesrc
1474 - weight
1475
1476 Their syntax is similar to the server line from the configuration file,
1477 please refer to their individual documentation for details.
Amaury Denoyellef99f77a2021-03-08 17:13:32 +01001478
William Lallemandaccac232020-04-02 17:42:51 +02001479add ssl crt-list <crtlist> <certificate>
1480add ssl crt-list <crtlist> <payload>
1481 Add an certificate in a crt-list. It can also be used for directories since
1482 directories are now loaded the same way as the crt-lists. This command allow
1483 you to use a certificate name in parameter, to use SSL options or filters a
1484 crt-list line must sent as a payload instead. Only one crt-list line is
1485 supported in the payload. This command will load the certificate for every
1486 bind lines using the crt-list. To push a new certificate to HAProxy the
1487 commands "new ssl cert" and "set ssl cert" must be used.
1488
1489 Example:
1490 $ echo "new ssl cert foobar.pem" | socat /tmp/sock1 -
1491 $ echo -e "set ssl cert foobar.pem <<\n$(cat foobar.pem)\n" | socat
1492 /tmp/sock1 -
1493 $ echo "commit ssl cert foobar.pem" | socat /tmp/sock1 -
1494 $ echo "add ssl crt-list certlist1 foobar.pem" | socat /tmp/sock1 -
1495
1496 $ echo -e 'add ssl crt-list certlist1 <<\nfoobar.pem [allow-0rtt] foo.bar.com
1497 !test1.com\n' | socat /tmp/sock1 -
1498
Willy Tarreau44aed902015-10-13 14:45:29 +02001499clear counters
1500 Clear the max values of the statistics counters in each proxy (frontend &
Willy Tarreaud80cb4e2018-01-20 19:30:13 +01001501 backend) and in each server. The accumulated counters are not affected. The
1502 internal activity counters reported by "show activity" are also reset. This
Willy Tarreau44aed902015-10-13 14:45:29 +02001503 can be used to get clean counters after an incident, without having to
1504 restart nor to clear traffic counters. This command is restricted and can
1505 only be issued on sockets configured for levels "operator" or "admin".
1506
1507clear counters all
1508 Clear all statistics counters in each proxy (frontend & backend) and in each
1509 server. This has the same effect as restarting. This command is restricted
1510 and can only be issued on sockets configured for level "admin".
1511
Willy Tarreauff3feeb2021-04-30 13:31:43 +02001512clear acl [@<ver>] <acl>
Willy Tarreau44aed902015-10-13 14:45:29 +02001513 Remove all entries from the acl <acl>. <acl> is the #<id> or the <file>
1514 returned by "show acl". Note that if the reference <acl> is a file and is
Willy Tarreauff3feeb2021-04-30 13:31:43 +02001515 shared with a map, this map will be also cleared. By default only the current
1516 version of the ACL is cleared (the one being matched against). However it is
1517 possible to specify another version using '@' followed by this version.
Willy Tarreau44aed902015-10-13 14:45:29 +02001518
Willy Tarreauff3feeb2021-04-30 13:31:43 +02001519clear map [@<ver>] <map>
Willy Tarreau44aed902015-10-13 14:45:29 +02001520 Remove all entries from the map <map>. <map> is the #<id> or the <file>
1521 returned by "show map". Note that if the reference <map> is a file and is
Willy Tarreauff3feeb2021-04-30 13:31:43 +02001522 shared with a acl, this acl will be also cleared. By default only the current
1523 version of the map is cleared (the one being matched against). However it is
1524 possible to specify another version using '@' followed by this version.
Willy Tarreau44aed902015-10-13 14:45:29 +02001525
1526clear table <table> [ data.<type> <operator> <value> ] | [ key <key> ]
1527 Remove entries from the stick-table <table>.
1528
1529 This is typically used to unblock some users complaining they have been
1530 abusively denied access to a service, but this can also be used to clear some
1531 stickiness entries matching a server that is going to be replaced (see "show
1532 table" below for details). Note that sometimes, removal of an entry will be
1533 refused because it is currently tracked by a session. Retrying a few seconds
1534 later after the session ends is usual enough.
1535
1536 In the case where no options arguments are given all entries will be removed.
1537
1538 When the "data." form is used entries matching a filter applied using the
1539 stored data (see "stick-table" in section 4.2) are removed. A stored data
1540 type must be specified in <type>, and this data type must be stored in the
1541 table otherwise an error is reported. The data is compared according to
1542 <operator> with the 64-bit integer <value>. Operators are the same as with
1543 the ACLs :
1544
1545 - eq : match entries whose data is equal to this value
1546 - ne : match entries whose data is not equal to this value
1547 - le : match entries whose data is less than or equal to this value
1548 - ge : match entries whose data is greater than or equal to this value
1549 - lt : match entries whose data is less than this value
1550 - gt : match entries whose data is greater than this value
1551
1552 When the key form is used the entry <key> is removed. The key must be of the
1553 same type as the table, which currently is limited to IPv4, IPv6, integer and
1554 string.
1555
1556 Example :
1557 $ echo "show table http_proxy" | socat stdio /tmp/sock1
1558 >>> # table: http_proxy, type: ip, size:204800, used:2
1559 >>> 0x80e6a4c: key=127.0.0.1 use=0 exp=3594729 gpc0=0 conn_rate(30000)=1 \
1560 bytes_out_rate(60000)=187
1561 >>> 0x80e6a80: key=127.0.0.2 use=0 exp=3594740 gpc0=1 conn_rate(30000)=10 \
1562 bytes_out_rate(60000)=191
1563
1564 $ echo "clear table http_proxy key 127.0.0.1" | socat stdio /tmp/sock1
1565
1566 $ echo "show table http_proxy" | socat stdio /tmp/sock1
1567 >>> # table: http_proxy, type: ip, size:204800, used:1
1568 >>> 0x80e6a80: key=127.0.0.2 use=0 exp=3594740 gpc0=1 conn_rate(30000)=10 \
1569 bytes_out_rate(60000)=191
1570 $ echo "clear table http_proxy data.gpc0 eq 1" | socat stdio /tmp/sock1
1571 $ echo "show table http_proxy" | socat stdio /tmp/sock1
1572 >>> # table: http_proxy, type: ip, size:204800, used:1
1573
Willy Tarreau7a562ca2021-04-30 15:10:01 +02001574commit acl @<ver> <acl>
1575 Commit all changes made to version <ver> of ACL <acl>, and deletes all past
1576 versions. <acl> is the #<id> or the <file> returned by "show acl". The
1577 version number must be between "curr_ver"+1 and "next_ver" as reported in
1578 "show acl". The contents to be committed to the ACL can be consulted with
1579 "show acl @<ver> <acl>" if desired. The specified version number has normally
1580 been created with the "prepare acl" command. The replacement is atomic. It
1581 consists in atomically updating the current version to the specified version,
1582 which will instantly cause all entries in other versions to become invisible,
1583 and all entries in the new version to become visible. It is also possible to
1584 use this command to perform an atomic removal of all visible entries of an
1585 ACL by calling "prepare acl" first then committing without adding any
1586 entries. This command cannot be used if the reference <acl> is a file also
1587 used as a map. In this case, the "commit map" command must be used instead.
1588
1589commit map @<ver> <map>
1590 Commit all changes made to version <ver> of map <map>, and deletes all past
1591 versions. <map> is the #<id> or the <file> returned by "show map". The
1592 version number must be between "curr_ver"+1 and "next_ver" as reported in
1593 "show map". The contents to be committed to the map can be consulted with
1594 "show map @<ver> <map>" if desired. The specified version number has normally
1595 been created with the "prepare map" command. The replacement is atomic. It
1596 consists in atomically updating the current version to the specified version,
1597 which will instantly cause all entries in other versions to become invisible,
1598 and all entries in the new version to become visible. It is also possible to
1599 use this command to perform an atomic removal of all visible entries of an
1600 map by calling "prepare map" first then committing without adding any
1601 entries.
1602
William Lallemand6ab08b32019-11-29 16:48:43 +01001603commit ssl cert <filename>
William Lallemandc184d872020-06-26 15:39:57 +02001604 Commit a temporary SSL certificate update transaction.
1605
1606 In the case of an existing certificate (in a "Used" state in "show ssl
1607 cert"), generate every SSL contextes and SNIs it need, insert them, and
1608 remove the previous ones. Replace in memory the previous SSL certificates
1609 everywhere the <filename> was used in the configuration. Upon failure it
1610 doesn't remove or insert anything. Once the temporary transaction is
1611 committed, it is destroyed.
1612
1613 In the case of a new certificate (after a "new ssl cert" and in a "Unused"
Ilya Shipitsin2272d8a2020-12-21 01:22:40 +05001614 state in "show ssl cert"), the certificate will be committed in a certificate
William Lallemandc184d872020-06-26 15:39:57 +02001615 storage, but it won't be used anywhere in haproxy. To use it and generate
1616 its SNIs you will need to add it to a crt-list or a directory with "add ssl
1617 crt-list".
William Lallemand6ab08b32019-11-29 16:48:43 +01001618
William Lallemandc184d872020-06-26 15:39:57 +02001619 See also "new ssl cert", "ssl set cert", "abort ssl cert" and
1620 "add ssl crt-list".
William Lallemand6ab08b32019-11-29 16:48:43 +01001621
Willy Tarreau6bdf3e92019-05-20 14:25:05 +02001622debug dev <command> [args]*
Willy Tarreaub24ab222019-10-24 18:03:39 +02001623 Call a developer-specific command. Only supported on a CLI connection running
1624 in expert mode (see "expert-mode on"). Such commands are extremely dangerous
1625 and not forgiving, any misuse may result in a crash of the process. They are
1626 intended for experts only, and must really not be used unless told to do so.
1627 Some of them are only available when haproxy is built with DEBUG_DEV defined
1628 because they may have security implications. All of these commands require
1629 admin privileges, and are purposely not documented to avoid encouraging their
1630 use by people who are not at ease with the source code.
Willy Tarreau6bdf3e92019-05-20 14:25:05 +02001631
Willy Tarreau44aed902015-10-13 14:45:29 +02001632del acl <acl> [<key>|#<ref>]
1633 Delete all the acl entries from the acl <acl> corresponding to the key <key>.
1634 <acl> is the #<id> or the <file> returned by "show acl". If the <ref> is used,
1635 this command delete only the listed reference. The reference can be found with
1636 listing the content of the acl. Note that if the reference <acl> is a file and
1637 is shared with a map, the entry will be also deleted in the map.
1638
1639del map <map> [<key>|#<ref>]
1640 Delete all the map entries from the map <map> corresponding to the key <key>.
1641 <map> is the #<id> or the <file> returned by "show map". If the <ref> is used,
1642 this command delete only the listed reference. The reference can be found with
1643 listing the content of the map. Note that if the reference <map> is a file and
1644 is shared with a acl, the entry will be also deleted in the map.
1645
William Lallemand419e6342020-04-08 12:05:39 +02001646del ssl cert <certfile>
1647 Delete a certificate store from HAProxy. The certificate must be unused and
1648 removed from any crt-list or directory. "show ssl cert" displays the status
1649 of the certificate. The deletion doesn't work with a certificate referenced
1650 directly with the "crt" directive in the configuration.
1651
William Lallemand0a9b9412020-04-06 17:43:05 +02001652del ssl crt-list <filename> <certfile[:line]>
1653 Delete an entry in a crt-list. This will delete every SNIs used for this
1654 entry in the frontends. If a certificate is used several time in a crt-list,
1655 you will need to provide which line you want to delete. To display the line
1656 numbers, use "show ssl crt-list -n <crtlist>".
1657
Amaury Denoyellee5580432021-04-15 14:41:20 +02001658del server <backend>/<server>
1659 Remove a server attached to the backend <backend>. Only valid on a server
1660 added at runtime. The server must be put in maintenance mode prior to its
1661 deletion. The operation is cancelled if the serveur still has active
1662 or idle connection or its connection queue is not empty.
1663
Willy Tarreau44aed902015-10-13 14:45:29 +02001664disable agent <backend>/<server>
1665 Mark the auxiliary agent check as temporarily stopped.
1666
1667 In the case where an agent check is being run as a auxiliary check, due
1668 to the agent-check parameter of a server directive, new checks are only
Dan Lloyd8e48b872016-07-01 21:01:18 -04001669 initialized when the agent is in the enabled. Thus, disable agent will
Willy Tarreau44aed902015-10-13 14:45:29 +02001670 prevent any new agent checks from begin initiated until the agent
1671 re-enabled using enable agent.
1672
1673 When an agent is disabled the processing of an auxiliary agent check that
1674 was initiated while the agent was set as enabled is as follows: All
1675 results that would alter the weight, specifically "drain" or a weight
1676 returned by the agent, are ignored. The processing of agent check is
1677 otherwise unchanged.
1678
1679 The motivation for this feature is to allow the weight changing effects
1680 of the agent checks to be paused to allow the weight of a server to be
1681 configured using set weight without being overridden by the agent.
1682
1683 This command is restricted and can only be issued on sockets configured for
1684 level "admin".
1685
Olivier Houchard614f8d72017-03-14 20:08:46 +01001686disable dynamic-cookie backend <backend>
Ilya Shipitsin2a950d02020-03-06 13:07:38 +05001687 Disable the generation of dynamic cookies for the backend <backend>
Olivier Houchard614f8d72017-03-14 20:08:46 +01001688
Willy Tarreau44aed902015-10-13 14:45:29 +02001689disable frontend <frontend>
1690 Mark the frontend as temporarily stopped. This corresponds to the mode which
1691 is used during a soft restart : the frontend releases the port but can be
1692 enabled again if needed. This should be used with care as some non-Linux OSes
1693 are unable to enable it back. This is intended to be used in environments
1694 where stopping a proxy is not even imaginable but a misconfigured proxy must
1695 be fixed. That way it's possible to release the port and bind it into another
1696 process to restore operations. The frontend will appear with status "STOP"
1697 on the stats page.
1698
1699 The frontend may be specified either by its name or by its numeric ID,
1700 prefixed with a sharp ('#').
1701
1702 This command is restricted and can only be issued on sockets configured for
1703 level "admin".
1704
1705disable health <backend>/<server>
1706 Mark the primary health check as temporarily stopped. This will disable
1707 sending of health checks, and the last health check result will be ignored.
1708 The server will be in unchecked state and considered UP unless an auxiliary
1709 agent check forces it down.
1710
1711 This command is restricted and can only be issued on sockets configured for
1712 level "admin".
1713
1714disable server <backend>/<server>
1715 Mark the server DOWN for maintenance. In this mode, no more checks will be
1716 performed on the server until it leaves maintenance.
1717 If the server is tracked by other servers, those servers will be set to DOWN
1718 during the maintenance.
1719
1720 In the statistics page, a server DOWN for maintenance will appear with a
1721 "MAINT" status, its tracking servers with the "MAINT(via)" one.
1722
1723 Both the backend and the server may be specified either by their name or by
1724 their numeric ID, prefixed with a sharp ('#').
1725
1726 This command is restricted and can only be issued on sockets configured for
1727 level "admin".
1728
1729enable agent <backend>/<server>
1730 Resume auxiliary agent check that was temporarily stopped.
1731
1732 See "disable agent" for details of the effect of temporarily starting
1733 and stopping an auxiliary agent.
1734
1735 This command is restricted and can only be issued on sockets configured for
1736 level "admin".
1737
Olivier Houchard614f8d72017-03-14 20:08:46 +01001738enable dynamic-cookie backend <backend>
n9@users.noreply.github.com25a1c8e2019-08-23 11:21:05 +02001739 Enable the generation of dynamic cookies for the backend <backend>.
1740 A secret key must also be provided.
Olivier Houchard614f8d72017-03-14 20:08:46 +01001741
Willy Tarreau44aed902015-10-13 14:45:29 +02001742enable frontend <frontend>
1743 Resume a frontend which was temporarily stopped. It is possible that some of
1744 the listening ports won't be able to bind anymore (eg: if another process
1745 took them since the 'disable frontend' operation). If this happens, an error
1746 is displayed. Some operating systems might not be able to resume a frontend
1747 which was disabled.
1748
1749 The frontend may be specified either by its name or by its numeric ID,
1750 prefixed with a sharp ('#').
1751
1752 This command is restricted and can only be issued on sockets configured for
1753 level "admin".
1754
1755enable health <backend>/<server>
1756 Resume a primary health check that was temporarily stopped. This will enable
1757 sending of health checks again. Please see "disable health" for details.
1758
1759 This command is restricted and can only be issued on sockets configured for
1760 level "admin".
1761
1762enable server <backend>/<server>
1763 If the server was previously marked as DOWN for maintenance, this marks the
1764 server UP and checks are re-enabled.
1765
1766 Both the backend and the server may be specified either by their name or by
1767 their numeric ID, prefixed with a sharp ('#').
1768
1769 This command is restricted and can only be issued on sockets configured for
1770 level "admin".
1771
Amaury Denoyelle18487fb2021-03-18 15:32:53 +01001772experimental-mode [on|off]
1773 Without options, this indicates whether the experimental mode is enabled or
1774 disabled on the current connection. When passed "on", it turns the
1775 experimental mode on for the current CLI connection only. With "off" it turns
1776 it off.
1777
1778 The experimental mode is used to access to extra features still in
1779 development. These features are currently not stable and should be used with
Ilya Shipitsinba13f162021-03-19 22:21:44 +05001780 care. They may be subject to breaking changes across versions.
Amaury Denoyelle18487fb2021-03-18 15:32:53 +01001781
Willy Tarreauabb9f9b2019-10-24 17:55:53 +02001782expert-mode [on|off]
Amaury Denoyelle18487fb2021-03-18 15:32:53 +01001783 This command is similar to experimental-mode but is used to toggle the
1784 expert mode.
1785
1786 The expert mode enables displaying of expert commands that can be extremely
Willy Tarreauabb9f9b2019-10-24 17:55:53 +02001787 dangerous for the process and which may occasionally help developers collect
1788 important information about complex bugs. Any misuse of these features will
1789 likely lead to a process crash. Do not use this option without being invited
1790 to do so. Note that this command is purposely not listed in the help message.
1791 This command is only accessible in admin level. Changing to another level
1792 automatically resets the expert mode.
1793
Willy Tarreau44aed902015-10-13 14:45:29 +02001794get map <map> <value>
1795get acl <acl> <value>
1796 Lookup the value <value> in the map <map> or in the ACL <acl>. <map> or <acl>
1797 are the #<id> or the <file> returned by "show map" or "show acl". This command
1798 returns all the matching patterns associated with this map. This is useful for
1799 debugging maps and ACLs. The output format is composed by one line par
1800 matching type. Each line is composed by space-delimited series of words.
1801
1802 The first two words are:
1803
1804 <match method>: The match method applied. It can be "found", "bool",
1805 "int", "ip", "bin", "len", "str", "beg", "sub", "dir",
1806 "dom", "end" or "reg".
1807
1808 <match result>: The result. Can be "match" or "no-match".
1809
1810 The following words are returned only if the pattern matches an entry.
1811
1812 <index type>: "tree" or "list". The internal lookup algorithm.
1813
1814 <case>: "case-insensitive" or "case-sensitive". The
1815 interpretation of the case.
1816
1817 <entry matched>: match="<entry>". Return the matched pattern. It is
1818 useful with regular expressions.
1819
1820 The two last word are used to show the returned value and its type. With the
1821 "acl" case, the pattern doesn't exist.
1822
1823 return=nothing: No return because there are no "map".
1824 return="<value>": The value returned in the string format.
1825 return=cannot-display: The value cannot be converted as string.
1826
1827 type="<type>": The type of the returned sample.
1828
Willy Tarreauc35eb382021-03-26 14:51:31 +01001829get var <name>
1830 Show the existence, type and contents of the process-wide variable 'name'.
1831 Only process-wide variables are readable, so the name must begin with
1832 'proc.' otherwise no variable will be found. This command requires levels
1833 "operator" or "admin".
1834
Willy Tarreau44aed902015-10-13 14:45:29 +02001835get weight <backend>/<server>
1836 Report the current weight and the initial weight of server <server> in
1837 backend <backend> or an error if either doesn't exist. The initial weight is
1838 the one that appears in the configuration file. Both are normally equal
1839 unless the current weight has been changed. Both the backend and the server
1840 may be specified either by their name or by their numeric ID, prefixed with a
1841 sharp ('#').
1842
Willy Tarreau0b1b8302021-05-09 20:59:23 +02001843help [<command>]
1844 Print the list of known keywords and their basic usage, or commands matching
1845 the requested one. The same help screen is also displayed for unknown
1846 commands.
Willy Tarreau44aed902015-10-13 14:45:29 +02001847
William Lallemandaccac232020-04-02 17:42:51 +02001848new ssl cert <filename>
1849 Create a new empty SSL certificate store to be filled with a certificate and
1850 added to a directory or a crt-list. This command should be used in
1851 combination with "set ssl cert" and "add ssl crt-list".
1852
Willy Tarreau97218ce2021-04-30 14:57:03 +02001853prepare acl <acl>
1854 Allocate a new version number in ACL <acl> for atomic replacement. <acl> is
1855 the #<id> or the <file> returned by "show acl". The new version number is
1856 shown in response after "New version created:". This number will then be
1857 usable to prepare additions of new entries into the ACL which will then
1858 atomically replace the current ones once committed. It is reported as
1859 "next_ver" in "show acl". There is no impact of allocating new versions, as
1860 unused versions will automatically be removed once a more recent version is
1861 committed. Version numbers are unsigned 32-bit values which wrap at the end,
1862 so care must be taken when comparing them in an external program. This
1863 command cannot be used if the reference <acl> is a file also used as a map.
1864 In this case, the "prepare map" command must be used instead.
1865
1866prepare map <map>
1867 Allocate a new version number in map <map> for atomic replacement. <map> is
1868 the #<id> or the <file> returned by "show map". The new version number is
1869 shown in response after "New version created:". This number will then be
1870 usable to prepare additions of new entries into the map which will then
1871 atomically replace the current ones once committed. It is reported as
1872 "next_ver" in "show map". There is no impact of allocating new versions, as
1873 unused versions will automatically be removed once a more recent version is
1874 committed. Version numbers are unsigned 32-bit values which wrap at the end,
1875 so care must be taken when comparing them in an external program.
1876
Willy Tarreau44aed902015-10-13 14:45:29 +02001877prompt
1878 Toggle the prompt at the beginning of the line and enter or leave interactive
1879 mode. In interactive mode, the connection is not closed after a command
1880 completes. Instead, the prompt will appear again, indicating the user that
1881 the interpreter is waiting for a new command. The prompt consists in a right
1882 angle bracket followed by a space "> ". This mode is particularly convenient
1883 when one wants to periodically check information such as stats or errors.
1884 It is also a good idea to enter interactive mode before issuing a "help"
1885 command.
1886
1887quit
1888 Close the connection when in interactive mode.
1889
Olivier Houchard614f8d72017-03-14 20:08:46 +01001890set dynamic-cookie-key backend <backend> <value>
1891 Modify the secret key used to generate the dynamic persistent cookies.
1892 This will break the existing sessions.
1893
Willy Tarreau44aed902015-10-13 14:45:29 +02001894set map <map> [<key>|#<ref>] <value>
1895 Modify the value corresponding to each key <key> in a map <map>. <map> is the
1896 #<id> or <file> returned by "show map". If the <ref> is used in place of
1897 <key>, only the entry pointed by <ref> is changed. The new value is <value>.
1898
1899set maxconn frontend <frontend> <value>
1900 Dynamically change the specified frontend's maxconn setting. Any positive
1901 value is allowed including zero, but setting values larger than the global
1902 maxconn does not make much sense. If the limit is increased and connections
1903 were pending, they will immediately be accepted. If it is lowered to a value
1904 below the current number of connections, new connections acceptation will be
1905 delayed until the threshold is reached. The frontend might be specified by
1906 either its name or its numeric ID prefixed with a sharp ('#').
1907
Andrew Hayworthedb93a72015-10-27 21:46:25 +00001908set maxconn server <backend/server> <value>
1909 Dynamically change the specified server's maxconn setting. Any positive
1910 value is allowed including zero, but setting values larger than the global
1911 maxconn does not make much sense.
1912
Willy Tarreau44aed902015-10-13 14:45:29 +02001913set maxconn global <maxconn>
1914 Dynamically change the global maxconn setting within the range defined by the
1915 initial global maxconn setting. If it is increased and connections were
1916 pending, they will immediately be accepted. If it is lowered to a value below
1917 the current number of connections, new connections acceptation will be
1918 delayed until the threshold is reached. A value of zero restores the initial
1919 setting.
1920
Willy Tarreau00dd44f2021-05-05 16:44:23 +02001921set profiling { tasks | memory } { auto | on | off }
1922 Enables or disables CPU or memory profiling for the indicated subsystem. This
1923 is equivalent to setting or clearing the "profiling" settings in the "global"
Willy Tarreaucfa71012021-01-29 11:56:21 +01001924 section of the configuration file. Please also see "show profiling". Note
1925 that manually setting the tasks profiling to "on" automatically resets the
1926 scheduler statistics, thus allows to check activity over a given interval.
Willy Tarreau00dd44f2021-05-05 16:44:23 +02001927 The memory profiling is limited to certain operating systems (known to work
1928 on the linux-glibc target), and requires USE_MEMORY_PROFILING to be set at
1929 compile time.
Willy Tarreau75c62c22018-11-22 11:02:09 +01001930
Willy Tarreau44aed902015-10-13 14:45:29 +02001931set rate-limit connections global <value>
1932 Change the process-wide connection rate limit, which is set by the global
1933 'maxconnrate' setting. A value of zero disables the limitation. This limit
1934 applies to all frontends and the change has an immediate effect. The value
1935 is passed in number of connections per second.
1936
1937set rate-limit http-compression global <value>
1938 Change the maximum input compression rate, which is set by the global
1939 'maxcomprate' setting. A value of zero disables the limitation. The value is
1940 passed in number of kilobytes per second. The value is available in the "show
1941 info" on the line "CompressBpsRateLim" in bytes.
1942
1943set rate-limit sessions global <value>
1944 Change the process-wide session rate limit, which is set by the global
1945 'maxsessrate' setting. A value of zero disables the limitation. This limit
1946 applies to all frontends and the change has an immediate effect. The value
1947 is passed in number of sessions per second.
1948
1949set rate-limit ssl-sessions global <value>
1950 Change the process-wide SSL session rate limit, which is set by the global
1951 'maxsslrate' setting. A value of zero disables the limitation. This limit
1952 applies to all frontends and the change has an immediate effect. The value
1953 is passed in number of sessions per second sent to the SSL stack. It applies
1954 before the handshake in order to protect the stack against handshake abuses.
1955
Baptiste Assmann3749ebf2016-08-03 22:34:12 +02001956set server <backend>/<server> addr <ip4 or ip6 address> [port <port>]
Willy Tarreau44aed902015-10-13 14:45:29 +02001957 Replace the current IP address of a server by the one provided.
Michael Prokop4438c602019-05-24 10:25:45 +02001958 Optionally, the port can be changed using the 'port' parameter.
Baptiste Assmann3749ebf2016-08-03 22:34:12 +02001959 Note that changing the port also support switching from/to port mapping
1960 (notation with +X or -Y), only if a port is configured for the health check.
Willy Tarreau44aed902015-10-13 14:45:29 +02001961
1962set server <backend>/<server> agent [ up | down ]
1963 Force a server's agent to a new state. This can be useful to immediately
1964 switch a server's state regardless of some slow agent checks for example.
1965 Note that the change is propagated to tracking servers if any.
1966
William Dauchy7cabc062021-02-11 22:51:24 +01001967set server <backend>/<server> agent-addr <addr> [port <port>]
Misiek43972902017-01-09 09:53:06 +01001968 Change addr for servers agent checks. Allows to migrate agent-checks to
1969 another address at runtime. You can specify both IP and hostname, it will be
1970 resolved.
William Dauchy7cabc062021-02-11 22:51:24 +01001971 Optionally, change the port agent.
1972
1973set server <backend>/<server> agent-port <port>
1974 Change the port used for agent checks.
Misiek43972902017-01-09 09:53:06 +01001975
1976set server <backend>/<server> agent-send <value>
1977 Change agent string sent to agent check target. Allows to update string while
1978 changing server address to keep those two matching.
1979
Willy Tarreau44aed902015-10-13 14:45:29 +02001980set server <backend>/<server> health [ up | stopping | down ]
1981 Force a server's health to a new state. This can be useful to immediately
1982 switch a server's state regardless of some slow health checks for example.
1983 Note that the change is propagated to tracking servers if any.
1984
William Dauchyb456e1f2021-02-11 22:51:23 +01001985set server <backend>/<server> check-addr <ip4 | ip6> [port <port>]
1986 Change the IP address used for server health checks.
1987 Optionally, change the port used for server health checks.
1988
Baptiste Assmann50946562016-08-31 23:26:29 +02001989set server <backend>/<server> check-port <port>
1990 Change the port used for health checking to <port>
1991
Willy Tarreau44aed902015-10-13 14:45:29 +02001992set server <backend>/<server> state [ ready | drain | maint ]
1993 Force a server's administrative state to a new state. This can be useful to
1994 disable load balancing and/or any traffic to a server. Setting the state to
1995 "ready" puts the server in normal mode, and the command is the equivalent of
1996 the "enable server" command. Setting the state to "maint" disables any traffic
1997 to the server as well as any health checks. This is the equivalent of the
1998 "disable server" command. Setting the mode to "drain" only removes the server
1999 from load balancing but still allows it to be checked and to accept new
2000 persistent connections. Changes are propagated to tracking servers if any.
2001
2002set server <backend>/<server> weight <weight>[%]
2003 Change a server's weight to the value passed in argument. This is the exact
2004 equivalent of the "set weight" command below.
2005
Frédéric Lécailleb418c122017-04-26 11:24:02 +02002006set server <backend>/<server> fqdn <FQDN>
Lukas Tribusc5dd5a52018-08-14 11:39:35 +02002007 Change a server's FQDN to the value passed in argument. This requires the
2008 internal run-time DNS resolver to be configured and enabled for this server.
Frédéric Lécailleb418c122017-04-26 11:24:02 +02002009
William Dauchyf6370442020-11-14 19:25:33 +01002010set server <backend>/<server> ssl [ on | off ]
2011 This option configures SSL ciphering on outgoing connections to the server.
2012
Andjelko Iharosc4df59e2017-07-20 11:59:48 +02002013set severity-output [ none | number | string ]
2014 Change the severity output format of the stats socket connected to for the
2015 duration of the current session.
2016
William Lallemand6ab08b32019-11-29 16:48:43 +01002017set ssl cert <filename> <payload>
2018 This command is part of a transaction system, the "commit ssl cert" and
2019 "abort ssl cert" commands could be required.
Remi Tricot-Le Breton34459092021-04-14 16:19:28 +02002020 This whole transaction system works on any certificate displayed by the
Remi Tricot-Le Bretonb5f0fac2021-04-14 16:19:29 +02002021 "show ssl cert" command, so on any frontend or backend certificate.
William Lallemand6ab08b32019-11-29 16:48:43 +01002022 If there is no on-going transaction, it will duplicate the certificate
2023 <filename> in memory to a temporary transaction, then update this
2024 transaction with the PEM file in the payload. If a transaction exists with
2025 the same filename, it will update this transaction. It's also possible to
2026 update the files linked to a certificate (.issuer, .sctl, .oscp etc.)
2027 Once the modification are done, you have to "commit ssl cert" the
2028 transaction.
2029
2030 Example:
2031 echo -e "set ssl cert localhost.pem <<\n$(cat 127.0.0.1.pem)\n" | \
2032 socat /var/run/haproxy.stat -
2033 echo -e \
2034 "set ssl cert localhost.pem.issuer <<\n $(cat 127.0.0.1.pem.issuer)\n" | \
2035 socat /var/run/haproxy.stat -
2036 echo -e \
2037 "set ssl cert localhost.pem.ocsp <<\n$(base64 -w 1000 127.0.0.1.pem.ocsp)\n" | \
2038 socat /var/run/haproxy.stat -
2039 echo "commit ssl cert localhost.pem" | socat /var/run/haproxy.stat -
2040
Aurélien Nephtali1e0867c2018-04-18 14:04:58 +02002041set ssl ocsp-response <response | payload>
Willy Tarreau44aed902015-10-13 14:45:29 +02002042 This command is used to update an OCSP Response for a certificate (see "crt"
2043 on "bind" lines). Same controls are performed as during the initial loading of
2044 the response. The <response> must be passed as a base64 encoded string of the
Emmanuel Hocdet2c32d8f2017-05-22 14:58:00 +02002045 DER encoded response from the OCSP server. This command is not supported with
2046 BoringSSL.
Willy Tarreau44aed902015-10-13 14:45:29 +02002047
2048 Example:
2049 openssl ocsp -issuer issuer.pem -cert server.pem \
2050 -host ocsp.issuer.com:80 -respout resp.der
2051 echo "set ssl ocsp-response $(base64 -w 10000 resp.der)" | \
2052 socat stdio /var/run/haproxy.stat
2053
Aurélien Nephtali1e0867c2018-04-18 14:04:58 +02002054 using the payload syntax:
2055 echo -e "set ssl ocsp-response <<\n$(base64 resp.der)\n" | \
2056 socat stdio /var/run/haproxy.stat
2057
Willy Tarreau44aed902015-10-13 14:45:29 +02002058set ssl tls-key <id> <tlskey>
2059 Set the next TLS key for the <id> listener to <tlskey>. This key becomes the
2060 ultimate key, while the penultimate one is used for encryption (others just
2061 decrypt). The oldest TLS key present is overwritten. <id> is either a numeric
2062 #<id> or <file> returned by "show tls-keys". <tlskey> is a base64 encoded 48
Emeric Brun9e754772019-01-10 17:51:55 +01002063 or 80 bits TLS ticket key (ex. openssl rand 80 | openssl base64 -A).
Willy Tarreau44aed902015-10-13 14:45:29 +02002064
2065set table <table> key <key> [data.<data_type> <value>]*
2066 Create or update a stick-table entry in the table. If the key is not present,
2067 an entry is inserted. See stick-table in section 4.2 to find all possible
2068 values for <data_type>. The most likely use consists in dynamically entering
2069 entries for source IP addresses, with a flag in gpc0 to dynamically block an
2070 IP address or affect its quality of service. It is possible to pass multiple
2071 data_types in a single call.
2072
2073set timeout cli <delay>
2074 Change the CLI interface timeout for current connection. This can be useful
2075 during long debugging sessions where the user needs to constantly inspect
2076 some indicators without being disconnected. The delay is passed in seconds.
2077
Willy Tarreau4000ff02021-04-30 14:45:53 +02002078set var <name> <expression>
2079 Allows to set or overwrite the process-wide variable 'name' with the result
2080 of expression <expression>. Only process-wide variables may be used, so the
2081 name must begin with 'proc.' otherwise no variable will be set. The
2082 <expression> may only involve "internal" sample fetch keywords and converters
2083 even though the most likely useful ones will be str('something') or int().
2084 Note that the command line parser doesn't know about quotes, so any space in
2085 the expression must be preceded by a backslash. This command requires levels
2086 "operator" or "admin". This command is only supported on a CLI connection
2087 running in experimental mode (see "experimental-mode on").
2088
Willy Tarreau44aed902015-10-13 14:45:29 +02002089set weight <backend>/<server> <weight>[%]
2090 Change a server's weight to the value passed in argument. If the value ends
2091 with the '%' sign, then the new weight will be relative to the initially
2092 configured weight. Absolute weights are permitted between 0 and 256.
2093 Relative weights must be positive with the resulting absolute weight is
2094 capped at 256. Servers which are part of a farm running a static
2095 load-balancing algorithm have stricter limitations because the weight
2096 cannot change once set. Thus for these servers, the only accepted values
2097 are 0 and 100% (or 0 and the initial weight). Changes take effect
2098 immediately, though certain LB algorithms require a certain amount of
2099 requests to consider changes. A typical usage of this command is to
2100 disable a server during an update by setting its weight to zero, then to
2101 enable it again after the update by setting it back to 100%. This command
2102 is restricted and can only be issued on sockets configured for level
2103 "admin". Both the backend and the server may be specified either by their
2104 name or by their numeric ID, prefixed with a sharp ('#').
2105
Willy Tarreau95f753e2021-04-30 12:09:54 +02002106show acl [[@<ver>] <acl>]
Willy Tarreaud6129fc2017-07-28 16:52:23 +02002107 Dump info about acl converters. Without argument, the list of all available
Willy Tarreau95f753e2021-04-30 12:09:54 +02002108 acls is returned. If a <acl> is specified, its contents are dumped. <acl> is
2109 the #<id> or <file>. By default the current version of the ACL is shown (the
2110 version currently being matched against and reported as 'curr_ver' in the ACL
2111 list). It is possible to instead dump other versions by prepending '@<ver>'
2112 before the ACL's identifier. The version works as a filter and non-existing
2113 versions will simply report no result. The dump format is the same as for the
2114 maps even for the sample values. The data returned are not a list of
2115 available ACL, but are the list of all patterns composing any ACL. Many of
2116 these patterns can be shared with maps.
Willy Tarreaud6129fc2017-07-28 16:52:23 +02002117
2118show backend
2119 Dump the list of backends available in the running process
2120
William Lallemand67a234f2018-12-13 09:05:45 +01002121show cli level
2122 Display the CLI level of the current CLI session. The result could be
2123 'admin', 'operator' or 'user'. See also the 'operator' and 'user' commands.
2124
2125 Example :
2126
2127 $ socat /tmp/sock1 readline
2128 prompt
2129 > operator
2130 > show cli level
2131 operator
2132 > user
2133 > show cli level
2134 user
2135 > operator
2136 Permission denied
2137
2138operator
2139 Decrease the CLI level of the current CLI session to operator. It can't be
Amaury Denoyelle18487fb2021-03-18 15:32:53 +01002140 increased. It also drops expert and experimental mode. See also "show cli
2141 level".
William Lallemand67a234f2018-12-13 09:05:45 +01002142
2143user
2144 Decrease the CLI level of the current CLI session to user. It can't be
Amaury Denoyelle18487fb2021-03-18 15:32:53 +01002145 increased. It also drops expert and experimental mode. See also "show cli
2146 level".
William Lallemand67a234f2018-12-13 09:05:45 +01002147
Willy Tarreau4c356932019-05-16 17:39:32 +02002148show activity
2149 Reports some counters about internal events that will help developers and
2150 more generally people who know haproxy well enough to narrow down the causes
2151 of reports of abnormal behaviours. A typical example would be a properly
2152 running process never sleeping and eating 100% of the CPU. The output fields
2153 will be made of one line per metric, and per-thread counters on the same
Thayne McCombscdbcca92021-01-07 21:24:41 -07002154 line. These counters are 32-bit and will wrap during the process's life, which
Willy Tarreau4c356932019-05-16 17:39:32 +02002155 is not a problem since calls to this command will typically be performed
2156 twice. The fields are purposely not documented so that their exact meaning is
2157 verified in the code where the counters are fed. These values are also reset
2158 by the "clear counters" command.
2159
William Lallemand51132162016-12-16 16:38:58 +01002160show cli sockets
2161 List CLI sockets. The output format is composed of 3 fields separated by
2162 spaces. The first field is the socket address, it can be a unix socket, a
2163 ipv4 address:port couple or a ipv6 one. Socket of other types won't be dump.
2164 The second field describe the level of the socket: 'admin', 'user' or
2165 'operator'. The last field list the processes on which the socket is bound,
2166 separated by commas, it can be numbers or 'all'.
2167
2168 Example :
2169
2170 $ echo 'show cli sockets' | socat stdio /tmp/sock1
2171 # socket lvl processes
2172 /tmp/sock1 admin all
2173 127.0.0.1:9999 user 2,3,4
2174 127.0.0.2:9969 user 2
2175 [::1]:9999 operator 2
2176
William Lallemand86d0df02017-11-24 21:36:45 +01002177show cache
Cyril Bonté7b888f12017-11-26 22:24:31 +01002178 List the configured caches and the objects stored in each cache tree.
William Lallemand86d0df02017-11-24 21:36:45 +01002179
2180 $ echo 'show cache' | socat stdio /tmp/sock1
2181 0x7f6ac6c5b03a: foobar (shctx:0x7f6ac6c5b000, available blocks:3918)
2182 1 2 3 4
2183
2184 1. pointer to the cache structure
2185 2. cache name
2186 3. pointer to the mmap area (shctx)
2187 4. number of blocks available for reuse in the shctx
2188
Remi Tricot-Le Bretone3e1e5f2020-11-27 15:48:40 +01002189 0x7f6ac6c5b4cc hash:286881868 vary:0x0011223344556677 size:39114 (39 blocks), refcount:9, expire:237
2190 1 2 3 4 5 6 7
William Lallemand86d0df02017-11-24 21:36:45 +01002191
2192 1. pointer to the cache entry
2193 2. first 32 bits of the hash
Remi Tricot-Le Bretone3e1e5f2020-11-27 15:48:40 +01002194 3. secondary hash of the entry in case of vary
2195 4. size of the object in bytes
2196 5. number of blocks used for the object
2197 6. number of transactions using the entry
2198 7. expiration time, can be negative if already expired
William Lallemand86d0df02017-11-24 21:36:45 +01002199
Willy Tarreauae795722016-02-16 11:27:28 +01002200show env [<name>]
2201 Dump one or all environment variables known by the process. Without any
2202 argument, all variables are dumped. With an argument, only the specified
2203 variable is dumped if it exists. Otherwise "Variable not found" is emitted.
2204 Variables are dumped in the same format as they are stored or returned by the
2205 "env" utility, that is, "<name>=<value>". This can be handy when debugging
2206 certain configuration files making heavy use of environment variables to
2207 ensure that they contain the expected values. This command is restricted and
2208 can only be issued on sockets configured for levels "operator" or "admin".
2209
Willy Tarreau35069f82016-11-25 09:16:37 +01002210show errors [<iid>|<proxy>] [request|response]
Willy Tarreau44aed902015-10-13 14:45:29 +02002211 Dump last known request and response errors collected by frontends and
2212 backends. If <iid> is specified, the limit the dump to errors concerning
Willy Tarreau234ba2d2016-11-25 08:39:10 +01002213 either frontend or backend whose ID is <iid>. Proxy ID "-1" will cause
2214 all instances to be dumped. If a proxy name is specified instead, its ID
Willy Tarreau35069f82016-11-25 09:16:37 +01002215 will be used as the filter. If "request" or "response" is added after the
2216 proxy name or ID, only request or response errors will be dumped. This
2217 command is restricted and can only be issued on sockets configured for
2218 levels "operator" or "admin".
Willy Tarreau44aed902015-10-13 14:45:29 +02002219
2220 The errors which may be collected are the last request and response errors
2221 caused by protocol violations, often due to invalid characters in header
2222 names. The report precisely indicates what exact character violated the
2223 protocol. Other important information such as the exact date the error was
2224 detected, frontend and backend names, the server name (when known), the
2225 internal session ID and the source address which has initiated the session
2226 are reported too.
2227
2228 All characters are returned, and non-printable characters are encoded. The
2229 most common ones (\t = 9, \n = 10, \r = 13 and \e = 27) are encoded as one
2230 letter following a backslash. The backslash itself is encoded as '\\' to
2231 avoid confusion. Other non-printable characters are encoded '\xNN' where
2232 NN is the two-digits hexadecimal representation of the character's ASCII
2233 code.
2234
2235 Lines are prefixed with the position of their first character, starting at 0
2236 for the beginning of the buffer. At most one input line is printed per line,
2237 and large lines will be broken into multiple consecutive output lines so that
2238 the output never goes beyond 79 characters wide. It is easy to detect if a
2239 line was broken, because it will not end with '\n' and the next line's offset
2240 will be followed by a '+' sign, indicating it is a continuation of previous
2241 line.
2242
2243 Example :
Willy Tarreau35069f82016-11-25 09:16:37 +01002244 $ echo "show errors -1 response" | socat stdio /tmp/sock1
Willy Tarreau44aed902015-10-13 14:45:29 +02002245 >>> [04/Mar/2009:15:46:56.081] backend http-in (#2) : invalid response
2246 src 127.0.0.1, session #54, frontend fe-eth0 (#1), server s2 (#1)
2247 response length 213 bytes, error at position 23:
2248
2249 00000 HTTP/1.0 200 OK\r\n
2250 00017 header/bizarre:blah\r\n
2251 00038 Location: blah\r\n
2252 00054 Long-line: this is a very long line which should b
2253 00104+ e broken into multiple lines on the output buffer,
2254 00154+ otherwise it would be too large to print in a ter
2255 00204+ minal\r\n
2256 00211 \r\n
2257
2258 In the example above, we see that the backend "http-in" which has internal
2259 ID 2 has blocked an invalid response from its server s2 which has internal
2260 ID 1. The request was on session 54 initiated by source 127.0.0.1 and
2261 received by frontend fe-eth0 whose ID is 1. The total response length was
2262 213 bytes when the error was detected, and the error was at byte 23. This
2263 is the slash ('/') in header name "header/bizarre", which is not a valid
2264 HTTP character for a header name.
2265
Willy Tarreau1d181e42019-08-30 11:17:01 +02002266show events [<sink>] [-w] [-n]
Willy Tarreau9f830d72019-08-26 18:17:04 +02002267 With no option, this lists all known event sinks and their types. With an
2268 option, it will dump all available events in the designated sink if it is of
Willy Tarreau1d181e42019-08-30 11:17:01 +02002269 type buffer. If option "-w" is passed after the sink name, then once the end
2270 of the buffer is reached, the command will wait for new events and display
2271 them. It is possible to stop the operation by entering any input (which will
2272 be discarded) or by closing the session. Finally, option "-n" is used to
2273 directly seek to the end of the buffer, which is often convenient when
2274 combined with "-w" to only report new events. For convenience, "-wn" or "-nw"
2275 may be used to enable both options at once.
Willy Tarreau9f830d72019-08-26 18:17:04 +02002276
Willy Tarreau7a4a0ac2017-07-25 19:32:50 +02002277show fd [<fd>]
2278 Dump the list of either all open file descriptors or just the one number <fd>
2279 if specified. This is only aimed at developers who need to observe internal
2280 states in order to debug complex issues such as abnormal CPU usages. One fd
2281 is reported per lines, and for each of them, its state in the poller using
2282 upper case letters for enabled flags and lower case for disabled flags, using
2283 "P" for "polled", "R" for "ready", "A" for "active", the events status using
2284 "H" for "hangup", "E" for "error", "O" for "output", "P" for "priority" and
2285 "I" for "input", a few other flags like "N" for "new" (just added into the fd
2286 cache), "U" for "updated" (received an update in the fd cache), "L" for
2287 "linger_risk", "C" for "cloned", then the cached entry position, the pointer
2288 to the internal owner, the pointer to the I/O callback and its name when
2289 known. When the owner is a connection, the connection flags, and the target
2290 are reported (frontend, proxy or server). When the owner is a listener, the
2291 listener's state and its frontend are reported. There is no point in using
2292 this command without a good knowledge of the internals. It's worth noting
2293 that the output format may evolve over time so this output must not be parsed
Willy Tarreau8050efe2021-01-21 08:26:06 +01002294 by tools designed to be durable. Some internal structure states may look
2295 suspicious to the function listing them, in this case the output line will be
2296 suffixed with an exclamation mark ('!'). This may help find a starting point
2297 when trying to diagnose an incident.
Willy Tarreau7a4a0ac2017-07-25 19:32:50 +02002298
Willy Tarreau27456202021-05-08 07:54:24 +02002299show info [typed|json] [desc] [float]
Willy Tarreau5d8b9792016-03-11 11:09:34 +01002300 Dump info about haproxy status on current process. If "typed" is passed as an
2301 optional argument, field numbers, names and types are emitted as well so that
2302 external monitoring products can easily retrieve, possibly aggregate, then
2303 report information found in fields they don't know. Each field is dumped on
Simon Horman05ee2132017-01-04 09:37:25 +01002304 its own line. If "json" is passed as an optional argument then
2305 information provided by "typed" output is provided in JSON format as a
2306 list of JSON objects. By default, the format contains only two columns
2307 delimited by a colon (':'). The left one is the field name and the right
2308 one is the value. It is very important to note that in typed output
2309 format, the dump for a single object is contiguous so that there is no
Willy Tarreau27456202021-05-08 07:54:24 +02002310 need for a consumer to store everything at once. If "float" is passed as an
2311 optional argument, some fields usually emitted as integers may switch to
2312 floats for higher accuracy. It is purposely unspecified which ones are
2313 concerned as this might evolve over time. Using this option implies that the
2314 consumer is able to process floats. The output format used is sprintf("%f").
Willy Tarreau5d8b9792016-03-11 11:09:34 +01002315
2316 When using the typed output format, each line is made of 4 columns delimited
2317 by colons (':'). The first column is a dot-delimited series of 3 elements. The
2318 first element is the numeric position of the field in the list (starting at
2319 zero). This position shall not change over time, but holes are to be expected,
2320 depending on build options or if some fields are deleted in the future. The
2321 second element is the field name as it appears in the default "show info"
2322 output. The third element is the relative process number starting at 1.
2323
2324 The rest of the line starting after the first colon follows the "typed output
2325 format" described in the section above. In short, the second column (after the
2326 first ':') indicates the origin, nature and scope of the variable. The third
2327 column indicates the type of the field, among "s32", "s64", "u32", "u64" and
2328 "str". Then the fourth column is the value itself, which the consumer knows
2329 how to parse thanks to column 3 and how to process thanks to column 2.
2330
2331 Thus the overall line format in typed mode is :
2332
2333 <field_pos>.<field_name>.<process_num>:<tags>:<type>:<value>
2334
Willy Tarreau6b19b142019-10-09 15:44:21 +02002335 When "desc" is appended to the command, one extra colon followed by a quoted
2336 string is appended with a description for the metric. At the time of writing,
2337 this is only supported for the "typed" and default output formats.
2338
Willy Tarreau5d8b9792016-03-11 11:09:34 +01002339 Example :
2340
2341 > show info
2342 Name: HAProxy
2343 Version: 1.7-dev1-de52ea-146
2344 Release_date: 2016/03/11
2345 Nbproc: 1
2346 Process_num: 1
2347 Pid: 28105
2348 Uptime: 0d 0h00m04s
2349 Uptime_sec: 4
2350 Memmax_MB: 0
2351 PoolAlloc_MB: 0
2352 PoolUsed_MB: 0
2353 PoolFailed: 0
2354 (...)
2355
2356 > show info typed
2357 0.Name.1:POS:str:HAProxy
2358 1.Version.1:POS:str:1.7-dev1-de52ea-146
2359 2.Release_date.1:POS:str:2016/03/11
2360 3.Nbproc.1:CGS:u32:1
2361 4.Process_num.1:KGP:u32:1
2362 5.Pid.1:SGP:u32:28105
2363 6.Uptime.1:MDP:str:0d 0h00m08s
2364 7.Uptime_sec.1:MDP:u32:8
2365 8.Memmax_MB.1:CLP:u32:0
2366 9.PoolAlloc_MB.1:MGP:u32:0
2367 10.PoolUsed_MB.1:MGP:u32:0
2368 11.PoolFailed.1:MCP:u32:0
2369 (...)
2370
Simon Horman1084a362016-11-21 17:00:24 +01002371 In the typed format, the presence of the process ID at the end of the
2372 first column makes it very easy to visually aggregate outputs from
2373 multiple processes.
Willy Tarreau5d8b9792016-03-11 11:09:34 +01002374 Example :
2375
2376 $ ( echo show info typed | socat /var/run/haproxy.sock1 ; \
2377 echo show info typed | socat /var/run/haproxy.sock2 ) | \
2378 sort -t . -k 1,1n -k 2,2 -k 3,3n
2379 0.Name.1:POS:str:HAProxy
2380 0.Name.2:POS:str:HAProxy
2381 1.Version.1:POS:str:1.7-dev1-868ab3-148
2382 1.Version.2:POS:str:1.7-dev1-868ab3-148
2383 2.Release_date.1:POS:str:2016/03/11
2384 2.Release_date.2:POS:str:2016/03/11
2385 3.Nbproc.1:CGS:u32:2
2386 3.Nbproc.2:CGS:u32:2
2387 4.Process_num.1:KGP:u32:1
2388 4.Process_num.2:KGP:u32:2
2389 5.Pid.1:SGP:u32:30120
2390 5.Pid.2:SGP:u32:30121
2391 6.Uptime.1:MDP:str:0d 0h01m28s
2392 6.Uptime.2:MDP:str:0d 0h01m28s
2393 (...)
Willy Tarreau44aed902015-10-13 14:45:29 +02002394
Simon Horman05ee2132017-01-04 09:37:25 +01002395 The format of JSON output is described in a schema which may be output
Simon Horman6f6bb382017-01-04 09:37:26 +01002396 using "show schema json".
Simon Horman05ee2132017-01-04 09:37:25 +01002397
2398 The JSON output contains no extra whitespace in order to reduce the
2399 volume of output. For human consumption passing the output through a
2400 pretty printer may be helpful. Example :
2401
2402 $ echo "show info json" | socat /var/run/haproxy.sock stdio | \
2403 python -m json.tool
2404
Simon Horman6f6bb382017-01-04 09:37:26 +01002405 The JSON output contains no extra whitespace in order to reduce the
2406 volume of output. For human consumption passing the output through a
2407 pretty printer may be helpful. Example :
2408
2409 $ echo "show info json" | socat /var/run/haproxy.sock stdio | \
2410 python -m json.tool
2411
Willy Tarreau95f753e2021-04-30 12:09:54 +02002412show map [[@<ver>] <map>]
Willy Tarreau44aed902015-10-13 14:45:29 +02002413 Dump info about map converters. Without argument, the list of all available
2414 maps is returned. If a <map> is specified, its contents are dumped. <map> is
Willy Tarreau95f753e2021-04-30 12:09:54 +02002415 the #<id> or <file>. By default the current version of the map is shown (the
2416 version currently being matched against and reported as 'curr_ver' in the map
2417 list). It is possible to instead dump other versions by prepending '@<ver>'
2418 before the map's identifier. The version works as a filter and non-existing
2419 versions will simply report no result.
2420
2421 In the output, the first column is a unique entry identifier, which is usable
2422 as a reference for operations "del map" and "set map". The second column is
Willy Tarreau44aed902015-10-13 14:45:29 +02002423 the pattern and the third column is the sample if available. The data returned
2424 are not directly a list of available maps, but are the list of all patterns
2425 composing any map. Many of these patterns can be shared with ACL.
2426
Willy Tarreau49962b52021-02-12 16:56:22 +01002427show peers [dict|-] [<peers section>]
Frédéric Lécaille21dde502019-04-15 13:50:23 +02002428 Dump info about the peers configured in "peers" sections. Without argument,
2429 the list of the peers belonging to all the "peers" sections are listed. If
2430 <peers section> is specified, only the information about the peers belonging
Willy Tarreau49962b52021-02-12 16:56:22 +01002431 to this "peers" section are dumped. When "dict" is specified before the peers
2432 section name, the entire Tx/Rx dictionary caches will also be dumped (very
2433 large). Passing "-" may be required to dump a peers section called "dict".
Frédéric Lécaille21dde502019-04-15 13:50:23 +02002434
Michael Prokop4438c602019-05-24 10:25:45 +02002435 Here are two examples of outputs where hostA, hostB and hostC peers belong to
Frédéric Lécaille21dde502019-04-15 13:50:23 +02002436 "sharedlb" peers sections. Only hostA and hostB are connected. Only hostA has
2437 sent data to hostB.
2438
2439 $ echo "show peers" | socat - /tmp/hostA
2440 0x55deb0224320: [15/Apr/2019:11:28:01] id=sharedlb state=0 flags=0x3 \
Emeric Brun0bbec0f2019-04-18 11:39:43 +02002441 resync_timeout=<PAST> task_calls=45122
Frédéric Lécaille21dde502019-04-15 13:50:23 +02002442 0x55deb022b540: id=hostC(remote) addr=127.0.0.12:10002 status=CONN \
2443 reconnect=4s confirm=0
2444 flags=0x0
2445 0x55deb022a440: id=hostA(local) addr=127.0.0.10:10000 status=NONE \
2446 reconnect=<NEVER> confirm=0
2447 flags=0x0
2448 0x55deb0227d70: id=hostB(remote) addr=127.0.0.11:10001 status=ESTA
2449 reconnect=2s confirm=0
Emeric Brun0bbec0f2019-04-18 11:39:43 +02002450 flags=0x20000200 appctx:0x55deb028fba0 st0=7 st1=0 task_calls=14456 \
2451 state=EST
Frédéric Lécaille21dde502019-04-15 13:50:23 +02002452 xprt=RAW src=127.0.0.1:37257 addr=127.0.0.10:10000
2453 remote_table:0x55deb0224a10 id=stkt local_id=1 remote_id=1
2454 last_local_table:0x55deb0224a10 id=stkt local_id=1 remote_id=1
2455 shared tables:
2456 0x55deb0224a10 local_id=1 remote_id=1 flags=0x0 remote_data=0x65
2457 last_acked=0 last_pushed=3 last_get=0 teaching_origin=0 update=3
2458 table:0x55deb022d6a0 id=stkt update=3 localupdate=3 \
2459 commitupdate=3 syncing=0
2460
2461 $ echo "show peers" | socat - /tmp/hostB
2462 0x55871b5ab320: [15/Apr/2019:11:28:03] id=sharedlb state=0 flags=0x3 \
Emeric Brun0bbec0f2019-04-18 11:39:43 +02002463 resync_timeout=<PAST> task_calls=3
Frédéric Lécaille21dde502019-04-15 13:50:23 +02002464 0x55871b5b2540: id=hostC(remote) addr=127.0.0.12:10002 status=CONN \
2465 reconnect=3s confirm=0
2466 flags=0x0
2467 0x55871b5b1440: id=hostB(local) addr=127.0.0.11:10001 status=NONE \
2468 reconnect=<NEVER> confirm=0
2469 flags=0x0
2470 0x55871b5aed70: id=hostA(remote) addr=127.0.0.10:10000 status=ESTA \
2471 reconnect=2s confirm=0
Emeric Brun0bbec0f2019-04-18 11:39:43 +02002472 flags=0x20000200 appctx:0x7fa46800ee00 st0=7 st1=0 task_calls=62356 \
2473 state=EST
Frédéric Lécaille21dde502019-04-15 13:50:23 +02002474 remote_table:0x55871b5ab960 id=stkt local_id=1 remote_id=1
2475 last_local_table:0x55871b5ab960 id=stkt local_id=1 remote_id=1
2476 shared tables:
2477 0x55871b5ab960 local_id=1 remote_id=1 flags=0x0 remote_data=0x65
2478 last_acked=3 last_pushed=0 last_get=3 teaching_origin=0 update=0
2479 table:0x55871b5b46a0 id=stkt update=1 localupdate=0 \
2480 commitupdate=0 syncing=0
2481
Willy Tarreau44aed902015-10-13 14:45:29 +02002482show pools
2483 Dump the status of internal memory pools. This is useful to track memory
2484 usage when suspecting a memory leak for example. It does exactly the same
2485 as the SIGQUIT when running in foreground except that it does not flush
2486 the pools.
2487
Willy Tarreau42712cb2021-05-05 17:48:13 +02002488show profiling [{all | status | tasks | memory}] [max_lines]
Willy Tarreau75c62c22018-11-22 11:02:09 +01002489 Dumps the current profiling settings, one per line, as well as the command
Willy Tarreau1bd67e92021-01-29 00:07:40 +01002490 needed to change them. When tasks profiling is enabled, some per-function
2491 statistics collected by the scheduler will also be emitted, with a summary
Willy Tarreau42712cb2021-05-05 17:48:13 +02002492 covering the number of calls, total/avg CPU time and total/avg latency. When
2493 memory profiling is enabled, some information such as the number of
2494 allocations/releases and their sizes will be reported. It is possible to
2495 limit the dump to only the profiling status, the tasks, or the memory
2496 profiling by specifying the respective keywords; by default all profiling
2497 information are dumped. It is also possible to limit the number of lines
2498 of output of each category by specifying a numeric limit. Please note that
2499 profiling is essentially aimed at developers since it gives hints about
2500 where CPU cycles or memory are wasted in the code. There is nothing useful
2501 to monitor there.
Willy Tarreau75c62c22018-11-22 11:02:09 +01002502
Willy Tarreau87ef3232021-01-29 12:01:46 +01002503show resolvers [<resolvers section id>]
2504 Dump statistics for the given resolvers section, or all resolvers sections
2505 if no section is supplied.
2506
2507 For each name server, the following counters are reported:
2508 sent: number of DNS requests sent to this server
2509 valid: number of DNS valid responses received from this server
2510 update: number of DNS responses used to update the server's IP address
2511 cname: number of CNAME responses
2512 cname_error: CNAME errors encountered with this server
2513 any_err: number of empty response (IE: server does not support ANY type)
2514 nx: non existent domain response received from this server
2515 timeout: how many time this server did not answer in time
2516 refused: number of requests refused by this server
2517 other: any other DNS errors
2518 invalid: invalid DNS response (from a protocol point of view)
2519 too_big: too big response
2520 outdated: number of response arrived too late (after an other name server)
2521
Willy Tarreau69f591e2020-07-01 07:00:59 +02002522show servers conn [<backend>]
2523 Dump the current and idle connections state of the servers belonging to the
2524 designated backend (or all backends if none specified). A backend name or
2525 identifier may be used.
2526
2527 The output consists in a header line showing the fields titles, then one
2528 server per line with for each, the backend name and ID, server name and ID,
2529 the address, port and a series or values. The number of fields varies
2530 depending on thread count.
2531
2532 Given the threaded nature of idle connections, it's important to understand
2533 that some values may change once read, and that as such, consistency within a
2534 line isn't granted. This output is mostly provided as a debugging tool and is
2535 not relevant to be routinely monitored nor graphed.
2536
Willy Tarreau44aed902015-10-13 14:45:29 +02002537show servers state [<backend>]
2538 Dump the state of the servers found in the running configuration. A backend
2539 name or identifier may be provided to limit the output to this backend only.
2540
2541 The dump has the following format:
2542 - first line contains the format version (1 in this specification);
2543 - second line contains the column headers, prefixed by a sharp ('#');
2544 - third line and next ones contain data;
2545 - each line starting by a sharp ('#') is considered as a comment.
2546
Dan Lloyd8e48b872016-07-01 21:01:18 -04002547 Since multiple versions of the output may co-exist, below is the list of
Willy Tarreau44aed902015-10-13 14:45:29 +02002548 fields and their order per file format version :
2549 1:
2550 be_id: Backend unique id.
2551 be_name: Backend label.
2552 srv_id: Server unique id (in the backend).
2553 srv_name: Server label.
2554 srv_addr: Server IP address.
2555 srv_op_state: Server operational state (UP/DOWN/...).
Cyril Bonté5b2ce8a2016-11-02 00:19:58 +01002556 0 = SRV_ST_STOPPED
2557 The server is down.
2558 1 = SRV_ST_STARTING
2559 The server is warming up (up but
2560 throttled).
2561 2 = SRV_ST_RUNNING
2562 The server is fully up.
2563 3 = SRV_ST_STOPPING
2564 The server is up but soft-stopping
2565 (eg: 404).
Willy Tarreau44aed902015-10-13 14:45:29 +02002566 srv_admin_state: Server administrative state (MAINT/DRAIN/...).
Cyril Bonté5b2ce8a2016-11-02 00:19:58 +01002567 The state is actually a mask of values :
2568 0x01 = SRV_ADMF_FMAINT
2569 The server was explicitly forced into
2570 maintenance.
2571 0x02 = SRV_ADMF_IMAINT
2572 The server has inherited the maintenance
2573 status from a tracked server.
2574 0x04 = SRV_ADMF_CMAINT
2575 The server is in maintenance because of
2576 the configuration.
2577 0x08 = SRV_ADMF_FDRAIN
2578 The server was explicitly forced into
2579 drain state.
2580 0x10 = SRV_ADMF_IDRAIN
2581 The server has inherited the drain status
2582 from a tracked server.
Baptiste Assmann89aa7f32016-11-02 21:31:27 +01002583 0x20 = SRV_ADMF_RMAINT
2584 The server is in maintenance because of an
2585 IP address resolution failure.
Frédéric Lécailleb418c122017-04-26 11:24:02 +02002586 0x40 = SRV_ADMF_HMAINT
2587 The server FQDN was set from stats socket.
2588
Willy Tarreau44aed902015-10-13 14:45:29 +02002589 srv_uweight: User visible server's weight.
2590 srv_iweight: Server's initial weight.
2591 srv_time_since_last_change: Time since last operational change.
2592 srv_check_status: Last health check status.
2593 srv_check_result: Last check result (FAILED/PASSED/...).
Cyril Bonté5b2ce8a2016-11-02 00:19:58 +01002594 0 = CHK_RES_UNKNOWN
2595 Initialized to this by default.
2596 1 = CHK_RES_NEUTRAL
2597 Valid check but no status information.
2598 2 = CHK_RES_FAILED
2599 Check failed.
2600 3 = CHK_RES_PASSED
2601 Check succeeded and server is fully up
2602 again.
2603 4 = CHK_RES_CONDPASS
2604 Check reports the server doesn't want new
2605 sessions.
Willy Tarreau44aed902015-10-13 14:45:29 +02002606 srv_check_health: Checks rise / fall current counter.
2607 srv_check_state: State of the check (ENABLED/PAUSED/...).
Cyril Bonté5b2ce8a2016-11-02 00:19:58 +01002608 The state is actually a mask of values :
2609 0x01 = CHK_ST_INPROGRESS
2610 A check is currently running.
2611 0x02 = CHK_ST_CONFIGURED
2612 This check is configured and may be
2613 enabled.
2614 0x04 = CHK_ST_ENABLED
2615 This check is currently administratively
2616 enabled.
2617 0x08 = CHK_ST_PAUSED
2618 Checks are paused because of maintenance
2619 (health only).
Willy Tarreau44aed902015-10-13 14:45:29 +02002620 srv_agent_state: State of the agent check (ENABLED/PAUSED/...).
Cyril Bonté5b2ce8a2016-11-02 00:19:58 +01002621 This state uses the same mask values as
2622 "srv_check_state", adding this specific one :
2623 0x10 = CHK_ST_AGENT
2624 Check is an agent check (otherwise it's a
2625 health check).
Willy Tarreau44aed902015-10-13 14:45:29 +02002626 bk_f_forced_id: Flag to know if the backend ID is forced by
2627 configuration.
2628 srv_f_forced_id: Flag to know if the server's ID is forced by
2629 configuration.
Frédéric Lécailleb418c122017-04-26 11:24:02 +02002630 srv_fqdn: Server FQDN.
Frédéric Lécaille31694712017-08-01 08:47:19 +02002631 srv_port: Server port.
Baptiste Assmann6d0f38f2018-07-02 17:00:54 +02002632 srvrecord: DNS SRV record associated to this SRV.
William Dauchyf6370442020-11-14 19:25:33 +01002633 srv_use_ssl: use ssl for server connections.
William Dauchyd1a7b852021-02-11 22:51:26 +01002634 srv_check_port: Server health check port.
2635 srv_check_addr: Server health check address.
2636 srv_agent_addr: Server health agent address.
2637 srv_agent_port: Server health agent port.
Willy Tarreau44aed902015-10-13 14:45:29 +02002638
2639show sess
2640 Dump all known sessions. Avoid doing this on slow connections as this can
2641 be huge. This command is restricted and can only be issued on sockets
Willy Tarreauc6e7a1b2020-06-28 01:24:12 +02002642 configured for levels "operator" or "admin". Note that on machines with
2643 quickly recycled connections, it is possible that this output reports less
2644 entries than really exist because it will dump all existing sessions up to
2645 the last one that was created before the command was entered; those which
2646 die in the mean time will not appear.
Willy Tarreau44aed902015-10-13 14:45:29 +02002647
2648show sess <id>
2649 Display a lot of internal information about the specified session identifier.
2650 This identifier is the first field at the beginning of the lines in the dumps
2651 of "show sess" (it corresponds to the session pointer). Those information are
2652 useless to most users but may be used by haproxy developers to troubleshoot a
2653 complex bug. The output format is intentionally not documented so that it can
2654 freely evolve depending on demands. You may find a description of all fields
2655 returned in src/dumpstats.c
2656
2657 The special id "all" dumps the states of all sessions, which must be avoided
2658 as much as possible as it is highly CPU intensive and can take a lot of time.
2659
Daniel Corbettc40edac2020-11-01 10:54:17 -05002660show stat [domain <dns|proxy>] [{<iid>|<proxy>} <type> <sid>] [typed|json] \
Willy Tarreau698097b2020-10-23 20:19:47 +02002661 [desc] [up|no-maint]
Daniel Corbettc40edac2020-11-01 10:54:17 -05002662 Dump statistics. The domain is used to select which statistics to print; dns
2663 and proxy are available for now. By default, the CSV format is used; you can
Amaury Denoyelle072f97e2020-10-05 11:49:37 +02002664 activate the extended typed output format described in the section above if
2665 "typed" is passed after the other arguments; or in JSON if "json" is passed
2666 after the other arguments. By passing <id>, <type> and <sid>, it is possible
2667 to dump only selected items :
Willy Tarreaua1b1ed52016-11-25 08:50:58 +01002668 - <iid> is a proxy ID, -1 to dump everything. Alternatively, a proxy name
2669 <proxy> may be specified. In this case, this proxy's ID will be used as
2670 the ID selector.
Willy Tarreau44aed902015-10-13 14:45:29 +02002671 - <type> selects the type of dumpable objects : 1 for frontends, 2 for
2672 backends, 4 for servers, -1 for everything. These values can be ORed,
2673 for example:
2674 1 + 2 = 3 -> frontend + backend.
2675 1 + 2 + 4 = 7 -> frontend + backend + server.
2676 - <sid> is a server ID, -1 to dump everything from the selected proxy.
2677
2678 Example :
2679 $ echo "show info;show stat" | socat stdio unix-connect:/tmp/sock1
2680 >>> Name: HAProxy
2681 Version: 1.4-dev2-49
2682 Release_date: 2009/09/23
2683 Nbproc: 1
2684 Process_num: 1
2685 (...)
2686
2687 # pxname,svname,qcur,qmax,scur,smax,slim,stot,bin,bout,dreq, (...)
2688 stats,FRONTEND,,,0,0,1000,0,0,0,0,0,0,,,,,OPEN,,,,,,,,,1,1,0, (...)
2689 stats,BACKEND,0,0,0,0,1000,0,0,0,0,0,,0,0,0,0,UP,0,0,0,,0,250,(...)
2690 (...)
2691 www1,BACKEND,0,0,0,0,1000,0,0,0,0,0,,0,0,0,0,UP,1,1,0,,0,250, (...)
2692
2693 $
2694
Willy Tarreau5d8b9792016-03-11 11:09:34 +01002695 In this example, two commands have been issued at once. That way it's easy to
2696 find which process the stats apply to in multi-process mode. This is not
2697 needed in the typed output format as the process number is reported on each
2698 line. Notice the empty line after the information output which marks the end
2699 of the first block. A similar empty line appears at the end of the second
2700 block (stats) so that the reader knows the output has not been truncated.
2701
2702 When "typed" is specified, the output format is more suitable to monitoring
2703 tools because it provides numeric positions and indicates the type of each
2704 output field. Each value stands on its own line with process number, element
2705 number, nature, origin and scope. This same format is available via the HTTP
2706 stats by passing ";typed" after the URI. It is very important to note that in
Dan Lloyd8e48b872016-07-01 21:01:18 -04002707 typed output format, the dump for a single object is contiguous so that there
Willy Tarreau5d8b9792016-03-11 11:09:34 +01002708 is no need for a consumer to store everything at once.
2709
Willy Tarreau698097b2020-10-23 20:19:47 +02002710 The "up" modifier will result in listing only servers which reportedly up or
2711 not checked. Those down, unresolved, or in maintenance will not be listed.
2712 This is analogous to the ";up" option on the HTTP stats. Similarly, the
2713 "no-maint" modifier will act like the ";no-maint" HTTP modifier and will
2714 result in disabled servers not to be listed. The difference is that those
2715 which are enabled but down will not be evicted.
2716
Willy Tarreau5d8b9792016-03-11 11:09:34 +01002717 When using the typed output format, each line is made of 4 columns delimited
2718 by colons (':'). The first column is a dot-delimited series of 5 elements. The
2719 first element is a letter indicating the type of the object being described.
2720 At the moment the following object types are known : 'F' for a frontend, 'B'
2721 for a backend, 'L' for a listener, and 'S' for a server. The second element
2722 The second element is a positive integer representing the unique identifier of
2723 the proxy the object belongs to. It is equivalent to the "iid" column of the
2724 CSV output and matches the value in front of the optional "id" directive found
2725 in the frontend or backend section. The third element is a positive integer
2726 containing the unique object identifier inside the proxy, and corresponds to
2727 the "sid" column of the CSV output. ID 0 is reported when dumping a frontend
2728 or a backend. For a listener or a server, this corresponds to their respective
2729 ID inside the proxy. The fourth element is the numeric position of the field
2730 in the list (starting at zero). This position shall not change over time, but
2731 holes are to be expected, depending on build options or if some fields are
2732 deleted in the future. The fifth element is the field name as it appears in
2733 the CSV output. The sixth element is a positive integer and is the relative
2734 process number starting at 1.
2735
2736 The rest of the line starting after the first colon follows the "typed output
2737 format" described in the section above. In short, the second column (after the
2738 first ':') indicates the origin, nature and scope of the variable. The third
Willy Tarreau589722e2021-05-08 07:46:44 +02002739 column indicates the field type, among "s32", "s64", "u32", "u64", "flt' and
Willy Tarreau5d8b9792016-03-11 11:09:34 +01002740 "str". Then the fourth column is the value itself, which the consumer knows
2741 how to parse thanks to column 3 and how to process thanks to column 2.
2742
Willy Tarreau6b19b142019-10-09 15:44:21 +02002743 When "desc" is appended to the command, one extra colon followed by a quoted
2744 string is appended with a description for the metric. At the time of writing,
2745 this is only supported for the "typed" output format.
2746
Willy Tarreau5d8b9792016-03-11 11:09:34 +01002747 Thus the overall line format in typed mode is :
2748
2749 <obj>.<px_id>.<id>.<fpos>.<fname>.<process_num>:<tags>:<type>:<value>
2750
2751 Here's an example of typed output format :
2752
2753 $ echo "show stat typed" | socat stdio unix-connect:/tmp/sock1
2754 F.2.0.0.pxname.1:MGP:str:private-frontend
2755 F.2.0.1.svname.1:MGP:str:FRONTEND
2756 F.2.0.8.bin.1:MGP:u64:0
2757 F.2.0.9.bout.1:MGP:u64:0
2758 F.2.0.40.hrsp_2xx.1:MGP:u64:0
2759 L.2.1.0.pxname.1:MGP:str:private-frontend
2760 L.2.1.1.svname.1:MGP:str:sock-1
2761 L.2.1.17.status.1:MGP:str:OPEN
2762 L.2.1.73.addr.1:MGP:str:0.0.0.0:8001
2763 S.3.13.60.rtime.1:MCP:u32:0
2764 S.3.13.61.ttime.1:MCP:u32:0
2765 S.3.13.62.agent_status.1:MGP:str:L4TOUT
2766 S.3.13.64.agent_duration.1:MGP:u64:2001
2767 S.3.13.65.check_desc.1:MCP:str:Layer4 timeout
2768 S.3.13.66.agent_desc.1:MCP:str:Layer4 timeout
2769 S.3.13.67.check_rise.1:MCP:u32:2
2770 S.3.13.68.check_fall.1:MCP:u32:3
2771 S.3.13.69.check_health.1:SGP:u32:0
2772 S.3.13.70.agent_rise.1:MaP:u32:1
2773 S.3.13.71.agent_fall.1:SGP:u32:1
2774 S.3.13.72.agent_health.1:SGP:u32:1
2775 S.3.13.73.addr.1:MCP:str:1.255.255.255:8888
2776 S.3.13.75.mode.1:MAP:str:http
2777 B.3.0.0.pxname.1:MGP:str:private-backend
2778 B.3.0.1.svname.1:MGP:str:BACKEND
2779 B.3.0.2.qcur.1:MGP:u32:0
2780 B.3.0.3.qmax.1:MGP:u32:0
2781 B.3.0.4.scur.1:MGP:u32:0
2782 B.3.0.5.smax.1:MGP:u32:0
2783 B.3.0.6.slim.1:MGP:u32:1000
2784 B.3.0.55.lastsess.1:MMP:s32:-1
2785 (...)
2786
Simon Horman1084a362016-11-21 17:00:24 +01002787 In the typed format, the presence of the process ID at the end of the
2788 first column makes it very easy to visually aggregate outputs from
2789 multiple processes, as show in the example below where each line appears
2790 for each process :
Willy Tarreau5d8b9792016-03-11 11:09:34 +01002791
2792 $ ( echo show stat typed | socat /var/run/haproxy.sock1 - ; \
2793 echo show stat typed | socat /var/run/haproxy.sock2 - ) | \
2794 sort -t . -k 1,1 -k 2,2n -k 3,3n -k 4,4n -k 5,5 -k 6,6n
2795 B.3.0.0.pxname.1:MGP:str:private-backend
2796 B.3.0.0.pxname.2:MGP:str:private-backend
2797 B.3.0.1.svname.1:MGP:str:BACKEND
2798 B.3.0.1.svname.2:MGP:str:BACKEND
2799 B.3.0.2.qcur.1:MGP:u32:0
2800 B.3.0.2.qcur.2:MGP:u32:0
2801 B.3.0.3.qmax.1:MGP:u32:0
2802 B.3.0.3.qmax.2:MGP:u32:0
2803 B.3.0.4.scur.1:MGP:u32:0
2804 B.3.0.4.scur.2:MGP:u32:0
2805 B.3.0.5.smax.1:MGP:u32:0
2806 B.3.0.5.smax.2:MGP:u32:0
2807 B.3.0.6.slim.1:MGP:u32:1000
2808 B.3.0.6.slim.2:MGP:u32:1000
2809 (...)
Willy Tarreau44aed902015-10-13 14:45:29 +02002810
Simon Horman05ee2132017-01-04 09:37:25 +01002811 The format of JSON output is described in a schema which may be output
Simon Horman6f6bb382017-01-04 09:37:26 +01002812 using "show schema json".
2813
2814 The JSON output contains no extra whitespace in order to reduce the
2815 volume of output. For human consumption passing the output through a
2816 pretty printer may be helpful. Example :
2817
2818 $ echo "show stat json" | socat /var/run/haproxy.sock stdio | \
2819 python -m json.tool
Simon Horman05ee2132017-01-04 09:37:25 +01002820
2821 The JSON output contains no extra whitespace in order to reduce the
2822 volume of output. For human consumption passing the output through a
2823 pretty printer may be helpful. Example :
2824
2825 $ echo "show stat json" | socat /var/run/haproxy.sock stdio | \
2826 python -m json.tool
2827
William Lallemandd4f946c2019-12-05 10:26:40 +01002828show ssl cert [<filename>]
Remi Tricot-Le Bretonb5f0fac2021-04-14 16:19:29 +02002829 Display the list of certificates used on frontends and backends.
2830 If a filename is prefixed by an asterisk, it is a transaction which is not
2831 committed yet. If a filename is specified, it will show details about the
2832 certificate. This command can be useful to check if a certificate was well
2833 updated. You can also display details on a transaction by prefixing the
2834 filename by an asterisk.
William Lallemandd4f946c2019-12-05 10:26:40 +01002835
2836 Example :
2837
2838 $ echo "@1 show ssl cert" | socat /var/run/haproxy.master -
2839 # transaction
2840 *test.local.pem
2841 # filename
2842 test.local.pem
2843
2844 $ echo "@1 show ssl cert test.local.pem" | socat /var/run/haproxy.master -
2845 Filename: test.local.pem
2846 Serial: 03ECC19BA54B25E85ABA46EE561B9A10D26F
2847 notBefore: Sep 13 21:20:24 2019 GMT
2848 notAfter: Dec 12 21:20:24 2019 GMT
2849 Issuer: /C=US/O=Let's Encrypt/CN=Let's Encrypt Authority X3
2850 Subject: /CN=test.local
2851 Subject Alternative Name: DNS:test.local, DNS:imap.test.local
2852 Algorithm: RSA2048
2853 SHA1 FingerPrint: 417A11CAE25F607B24F638B4A8AEE51D1E211477
2854
2855 $ echo "@1 show ssl cert *test.local.pem" | socat /var/run/haproxy.master -
2856 Filename: *test.local.pem
2857 [...]
2858
William Lallemandc69f02d2020-04-06 19:07:03 +02002859show ssl crt-list [-n] [<filename>]
William Lallemandaccac232020-04-02 17:42:51 +02002860 Display the list of crt-list and directories used in the HAProxy
William Lallemandc69f02d2020-04-06 19:07:03 +02002861 configuration. If a filename is specified, dump the content of a crt-list or
2862 a directory. Once dumped the output can be used as a crt-list file.
2863 The '-n' option can be used to display the line number, which is useful when
2864 combined with the 'del ssl crt-list' option when a entry is duplicated. The
2865 output with the '-n' option is not compatible with the crt-list format and
2866 not loadable by haproxy.
William Lallemandaccac232020-04-02 17:42:51 +02002867
2868 Example:
William Lallemandc69f02d2020-04-06 19:07:03 +02002869 echo "show ssl crt-list -n localhost.crt-list" | socat /tmp/sock1 -
William Lallemandaccac232020-04-02 17:42:51 +02002870 # localhost.crt-list
William Lallemandc69f02d2020-04-06 19:07:03 +02002871 common.pem:1 !not.test1.com *.test1.com !localhost
2872 common.pem:2
2873 ecdsa.pem:3 [verify none allow-0rtt ssl-min-ver TLSv1.0 ssl-max-ver TLSv1.3] localhost !www.test1.com
2874 ecdsa.pem:4 [verify none allow-0rtt ssl-min-ver TLSv1.0 ssl-max-ver TLSv1.3]
William Lallemandaccac232020-04-02 17:42:51 +02002875
Willy Tarreau44aed902015-10-13 14:45:29 +02002876show table
2877 Dump general information on all known stick-tables. Their name is returned
2878 (the name of the proxy which holds them), their type (currently zero, always
2879 IP), their size in maximum possible number of entries, and the number of
2880 entries currently in use.
2881
2882 Example :
2883 $ echo "show table" | socat stdio /tmp/sock1
2884 >>> # table: front_pub, type: ip, size:204800, used:171454
2885 >>> # table: back_rdp, type: ip, size:204800, used:0
2886
Adis Nezirovic1a693fc2020-01-16 15:19:29 +01002887show table <name> [ data.<type> <operator> <value> [data.<type> ...]] | [ key <key> ]
Willy Tarreau44aed902015-10-13 14:45:29 +02002888 Dump contents of stick-table <name>. In this mode, a first line of generic
2889 information about the table is reported as with "show table", then all
2890 entries are dumped. Since this can be quite heavy, it is possible to specify
2891 a filter in order to specify what entries to display.
2892
2893 When the "data." form is used the filter applies to the stored data (see
2894 "stick-table" in section 4.2). A stored data type must be specified
2895 in <type>, and this data type must be stored in the table otherwise an
2896 error is reported. The data is compared according to <operator> with the
2897 64-bit integer <value>. Operators are the same as with the ACLs :
2898
2899 - eq : match entries whose data is equal to this value
2900 - ne : match entries whose data is not equal to this value
2901 - le : match entries whose data is less than or equal to this value
2902 - ge : match entries whose data is greater than or equal to this value
2903 - lt : match entries whose data is less than this value
2904 - gt : match entries whose data is greater than this value
2905
Adis Nezirovic1a693fc2020-01-16 15:19:29 +01002906 In this form, you can use multiple data filter entries, up to a maximum
2907 defined during build time (4 by default).
Willy Tarreau44aed902015-10-13 14:45:29 +02002908
2909 When the key form is used the entry <key> is shown. The key must be of the
2910 same type as the table, which currently is limited to IPv4, IPv6, integer,
2911 and string.
2912
2913 Example :
2914 $ echo "show table http_proxy" | socat stdio /tmp/sock1
2915 >>> # table: http_proxy, type: ip, size:204800, used:2
2916 >>> 0x80e6a4c: key=127.0.0.1 use=0 exp=3594729 gpc0=0 conn_rate(30000)=1 \
2917 bytes_out_rate(60000)=187
2918 >>> 0x80e6a80: key=127.0.0.2 use=0 exp=3594740 gpc0=1 conn_rate(30000)=10 \
2919 bytes_out_rate(60000)=191
2920
2921 $ echo "show table http_proxy data.gpc0 gt 0" | socat stdio /tmp/sock1
2922 >>> # table: http_proxy, type: ip, size:204800, used:2
2923 >>> 0x80e6a80: key=127.0.0.2 use=0 exp=3594740 gpc0=1 conn_rate(30000)=10 \
2924 bytes_out_rate(60000)=191
2925
2926 $ echo "show table http_proxy data.conn_rate gt 5" | \
2927 socat stdio /tmp/sock1
2928 >>> # table: http_proxy, type: ip, size:204800, used:2
2929 >>> 0x80e6a80: key=127.0.0.2 use=0 exp=3594740 gpc0=1 conn_rate(30000)=10 \
2930 bytes_out_rate(60000)=191
2931
2932 $ echo "show table http_proxy key 127.0.0.2" | \
2933 socat stdio /tmp/sock1
2934 >>> # table: http_proxy, type: ip, size:204800, used:2
2935 >>> 0x80e6a80: key=127.0.0.2 use=0 exp=3594740 gpc0=1 conn_rate(30000)=10 \
2936 bytes_out_rate(60000)=191
2937
2938 When the data criterion applies to a dynamic value dependent on time such as
2939 a bytes rate, the value is dynamically computed during the evaluation of the
2940 entry in order to decide whether it has to be dumped or not. This means that
2941 such a filter could match for some time then not match anymore because as
2942 time goes, the average event rate drops.
2943
2944 It is possible to use this to extract lists of IP addresses abusing the
2945 service, in order to monitor them or even blacklist them in a firewall.
2946 Example :
2947 $ echo "show table http_proxy data.gpc0 gt 0" \
2948 | socat stdio /tmp/sock1 \
2949 | fgrep 'key=' | cut -d' ' -f2 | cut -d= -f2 > abusers-ip.txt
2950 ( or | awk '/key/{ print a[split($2,a,"=")]; }' )
2951
Willy Tarreau7eff06e2021-01-29 11:32:55 +01002952show tasks
2953 Dumps the number of tasks currently in the run queue, with the number of
2954 occurrences for each function, and their average latency when it's known
2955 (for pure tasks with task profiling enabled). The dump is a snapshot of the
2956 instant it's done, and there may be variations depending on what tasks are
2957 left in the queue at the moment it happens, especially in mono-thread mode
2958 as there's less chance that I/Os can refill the queue (unless the queue is
2959 full). This command takes exclusive access to the process and can cause
2960 minor but measurable latencies when issued on a highly loaded process, so
2961 it must not be abused by monitoring bots.
2962
Willy Tarreau4e2b6462019-05-16 17:44:30 +02002963show threads
2964 Dumps some internal states and structures for each thread, that may be useful
2965 to help developers understand a problem. The output tries to be readable by
Willy Tarreauc7091d82019-05-17 10:08:49 +02002966 showing one block per thread. When haproxy is built with USE_THREAD_DUMP=1,
2967 an advanced dump mechanism involving thread signals is used so that each
2968 thread can dump its own state in turn. Without this option, the thread
2969 processing the command shows all its details but the other ones are less
Willy Tarreaue6a02fa2019-05-22 07:06:44 +02002970 detailed. A star ('*') is displayed in front of the thread handling the
2971 command. A right angle bracket ('>') may also be displayed in front of
2972 threads which didn't make any progress since last invocation of this command,
2973 indicating a bug in the code which must absolutely be reported. When this
2974 happens between two threads it usually indicates a deadlock. If a thread is
2975 alone, it's a different bug like a corrupted list. In all cases the process
2976 needs is not fully functional anymore and needs to be restarted.
2977
2978 The output format is purposely not documented so that it can easily evolve as
2979 new needs are identified, without having to maintain any form of backwards
2980 compatibility, and just like with "show activity", the values are meaningless
2981 without the code at hand.
Willy Tarreau4e2b6462019-05-16 17:44:30 +02002982
William Lallemandbb933462016-05-31 21:09:53 +02002983show tls-keys [id|*]
2984 Dump all loaded TLS ticket keys references. The TLS ticket key reference ID
2985 and the file from which the keys have been loaded is shown. Both of those
2986 can be used to update the TLS keys using "set ssl tls-key". If an ID is
2987 specified as parameter, it will dump the tickets, using * it will dump every
2988 keys from every references.
Willy Tarreau44aed902015-10-13 14:45:29 +02002989
Simon Horman6f6bb382017-01-04 09:37:26 +01002990show schema json
2991 Dump the schema used for the output of "show info json" and "show stat json".
2992
2993 The contains no extra whitespace in order to reduce the volume of output.
2994 For human consumption passing the output through a pretty printer may be
2995 helpful. Example :
2996
2997 $ echo "show schema json" | socat /var/run/haproxy.sock stdio | \
2998 python -m json.tool
2999
3000 The schema follows "JSON Schema" (json-schema.org) and accordingly
3001 verifiers may be used to verify the output of "show info json" and "show
3002 stat json" against the schema.
3003
Willy Tarreauf909c912019-08-22 20:06:04 +02003004show trace [<source>]
3005 Show the current trace status. For each source a line is displayed with a
3006 single-character status indicating if the trace is stopped, waiting, or
3007 running. The output sink used by the trace is indicated (or "none" if none
3008 was set), as well as the number of dropped events in this sink, followed by a
3009 brief description of the source. If a source name is specified, a detailed
3010 list of all events supported by the source, and their status for each action
3011 (report, start, pause, stop), indicated by a "+" if they are enabled, or a
3012 "-" otherwise. All these events are independent and an event might trigger
3013 a start without being reported and conversely.
Simon Horman6f6bb382017-01-04 09:37:26 +01003014
Willy Tarreau44aed902015-10-13 14:45:29 +02003015shutdown frontend <frontend>
3016 Completely delete the specified frontend. All the ports it was bound to will
3017 be released. It will not be possible to enable the frontend anymore after
3018 this operation. This is intended to be used in environments where stopping a
3019 proxy is not even imaginable but a misconfigured proxy must be fixed. That
3020 way it's possible to release the port and bind it into another process to
3021 restore operations. The frontend will not appear at all on the stats page
3022 once it is terminated.
3023
3024 The frontend may be specified either by its name or by its numeric ID,
3025 prefixed with a sharp ('#').
3026
3027 This command is restricted and can only be issued on sockets configured for
3028 level "admin".
3029
3030shutdown session <id>
3031 Immediately terminate the session matching the specified session identifier.
3032 This identifier is the first field at the beginning of the lines in the dumps
3033 of "show sess" (it corresponds to the session pointer). This can be used to
3034 terminate a long-running session without waiting for a timeout or when an
3035 endless transfer is ongoing. Such terminated sessions are reported with a 'K'
3036 flag in the logs.
3037
3038shutdown sessions server <backend>/<server>
3039 Immediately terminate all the sessions attached to the specified server. This
3040 can be used to terminate long-running sessions after a server is put into
3041 maintenance mode, for instance. Such terminated sessions are reported with a
3042 'K' flag in the logs.
3043
Willy Tarreauf909c912019-08-22 20:06:04 +02003044trace
3045 The "trace" command alone lists the trace sources, their current status, and
3046 their brief descriptions. It is only meant as a menu to enter next levels,
3047 see other "trace" commands below.
3048
3049trace 0
3050 Immediately stops all traces. This is made to be used as a quick solution
3051 to terminate a debugging session or as an emergency action to be used in case
3052 complex traces were enabled on multiple sources and impact the service.
3053
3054trace <source> event [ [+|-|!]<name> ]
3055 Without argument, this will list all the events supported by the designated
3056 source. They are prefixed with a "-" if they are not enabled, or a "+" if
3057 they are enabled. It is important to note that a single trace may be labelled
3058 with multiple events, and as long as any of the enabled events matches one of
3059 the events labelled on the trace, the event will be passed to the trace
3060 subsystem. For example, receiving an HTTP/2 frame of type HEADERS may trigger
3061 a frame event and a stream event since the frame creates a new stream. If
3062 either the frame event or the stream event are enabled for this source, the
3063 frame will be passed to the trace framework.
3064
3065 With an argument, it is possible to toggle the state of each event and
3066 individually enable or disable them. Two special keywords are supported,
3067 "none", which matches no event, and is used to disable all events at once,
3068 and "any" which matches all events, and is used to enable all events at
3069 once. Other events are specific to the event source. It is possible to
3070 enable one event by specifying its name, optionally prefixed with '+' for
3071 better readability. It is possible to disable one event by specifying its
3072 name prefixed by a '-' or a '!'.
3073
3074 One way to completely disable a trace source is to pass "event none", and
3075 this source will instantly be totally ignored.
3076
3077trace <source> level [<level>]
Willy Tarreau2ea549b2019-08-29 08:01:48 +02003078 Without argument, this will list all trace levels for this source, and the
Willy Tarreauf909c912019-08-22 20:06:04 +02003079 current one will be indicated by a star ('*') prepended in front of it. With
Willy Tarreau2ea549b2019-08-29 08:01:48 +02003080 an argument, this will change the trace level to the specified level. Detail
Willy Tarreauf909c912019-08-22 20:06:04 +02003081 levels are a form of filters that are applied before reporting the events.
Willy Tarreau2ea549b2019-08-29 08:01:48 +02003082 These filters are used to selectively include or exclude events depending on
3083 their level of importance. For example a developer might need to know
3084 precisely where in the code an HTTP header was considered invalid while the
3085 end user may not even care about this header's validity at all. There are
3086 currently 5 distinct levels for a trace :
Willy Tarreauf909c912019-08-22 20:06:04 +02003087
3088 user this will report information that are suitable for use by a
3089 regular haproxy user who wants to observe his traffic.
3090 Typically some HTTP requests and responses will be reported
3091 without much detail. Most sources will set this as the
3092 default level to ease operations.
3093
Willy Tarreau2ea549b2019-08-29 08:01:48 +02003094 proto in addition to what is reported at the "user" level, it also
3095 displays protocol-level updates. This can for example be the
3096 frame types or HTTP headers after decoding.
Willy Tarreauf909c912019-08-22 20:06:04 +02003097
3098 state in addition to what is reported at the "proto" level, it
3099 will also display state transitions (or failed transitions)
3100 which happen in parsers, so this will show attempts to
3101 perform an operation while the "proto" level only shows
3102 the final operation.
3103
Willy Tarreau2ea549b2019-08-29 08:01:48 +02003104 data in addition to what is reported at the "state" level, it
3105 will also include data transfers between the various layers.
3106
Willy Tarreauf909c912019-08-22 20:06:04 +02003107 developer it reports everything available, which can include advanced
3108 information such as "breaking out of this loop" that are
3109 only relevant to a developer trying to understand a bug that
Willy Tarreau09fb0df2019-08-29 08:40:59 +02003110 only happens once in a while in field. Function names are
3111 only reported at this level.
Willy Tarreauf909c912019-08-22 20:06:04 +02003112
3113 It is highly recommended to always use the "user" level only and switch to
3114 other levels only if instructed to do so by a developer. Also it is a good
3115 idea to first configure the events before switching to higher levels, as it
3116 may save from dumping many lines if no filter is applied.
3117
3118trace <source> lock [criterion]
3119 Without argument, this will list all the criteria supported by this source
3120 for lock-on processing, and display the current choice by a star ('*') in
3121 front of it. Lock-on means that the source will focus on the first matching
3122 event and only stick to the criterion which triggered this event, and ignore
3123 all other ones until the trace stops. This allows for example to take a trace
3124 on a single connection or on a single stream. The following criteria are
3125 supported by some traces, though not necessarily all, since some of them
3126 might not be available to the source :
3127
3128 backend lock on the backend that started the trace
3129 connection lock on the connection that started the trace
3130 frontend lock on the frontend that started the trace
3131 listener lock on the listener that started the trace
3132 nothing do not lock on anything
3133 server lock on the server that started the trace
3134 session lock on the session that started the trace
3135 thread lock on the thread that started the trace
3136
3137 In addition to this, each source may provide up to 4 specific criteria such
3138 as internal states or connection IDs. For example in HTTP/2 it is possible
3139 to lock on the H2 stream and ignore other streams once a strace starts.
3140
3141 When a criterion is passed in argument, this one is used instead of the
3142 other ones and any existing tracking is immediately terminated so that it can
3143 restart with the new criterion. The special keyword "nothing" is supported by
3144 all sources to permanently disable tracking.
3145
3146trace <source> { pause | start | stop } [ [+|-|!]event]
3147 Without argument, this will list the events enabled to automatically pause,
3148 start, or stop a trace for this source. These events are specific to each
3149 trace source. With an argument, this will either enable the event for the
3150 specified action (if optionally prefixed by a '+') or disable it (if
3151 prefixed by a '-' or '!'). The special keyword "now" is not an event and
3152 requests to take the action immediately. The keywords "none" and "any" are
3153 supported just like in "trace event".
3154
3155 The 3 supported actions are respectively "pause", "start" and "stop". The
3156 "pause" action enumerates events which will cause a running trace to stop and
3157 wait for a new start event to restart it. The "start" action enumerates the
3158 events which switch the trace into the waiting mode until one of the start
3159 events appears. And the "stop" action enumerates the events which definitely
3160 stop the trace until it is manually enabled again. In practice it makes sense
3161 to manually start a trace using "start now" without caring about events, and
3162 to stop it using "stop now". In order to capture more subtle event sequences,
3163 setting "start" to a normal event (like receiving an HTTP request) and "stop"
3164 to a very rare event like emitting a certain error, will ensure that the last
3165 captured events will match the desired criteria. And the pause event is
3166 useful to detect the end of a sequence, disable the lock-on and wait for
3167 another opportunity to take a capture. In this case it can make sense to
3168 enable lock-on to spot only one specific criterion (e.g. a stream), and have
3169 "start" set to anything that starts this criterion (e.g. all events which
3170 create a stream), "stop" set to the expected anomaly, and "pause" to anything
3171 that ends that criterion (e.g. any end of stream event). In this case the
3172 trace log will contain complete sequences of perfectly clean series affecting
3173 a single object, until the last sequence containing everything from the
3174 beginning to the anomaly.
3175
3176trace <source> sink [<sink>]
3177 Without argument, this will list all event sinks available for this source,
3178 and the currently configured one will have a star ('*') prepended in front
3179 of it. Sink "none" is always available and means that all events are simply
3180 dropped, though their processing is not ignored (e.g. lock-on does occur).
3181 Other sinks are available depending on configuration and build options, but
3182 typically "stdout" and "stderr" will be usable in debug mode, and in-memory
3183 ring buffers should be available as well. When a name is specified, the sink
3184 instantly changes for the specified source. Events are not changed during a
3185 sink change. In the worst case some may be lost if an invalid sink is used
3186 (or "none"), but operations do continue to a different destination.
3187
Willy Tarreau370a6942019-08-29 08:24:16 +02003188trace <source> verbosity [<level>]
3189 Without argument, this will list all verbosity levels for this source, and the
3190 current one will be indicated by a star ('*') prepended in front of it. With
3191 an argument, this will change the verbosity level to the specified one.
3192
3193 Verbosity levels indicate how far the trace decoder should go to provide
3194 detailed information. It depends on the trace source, since some sources will
3195 not even provide a specific decoder. Level "quiet" is always available and
3196 disables any decoding. It can be useful when trying to figure what's
3197 happening before trying to understand the details, since it will have a very
3198 low impact on performance and trace size. When no verbosity levels are
3199 declared by a source, level "default" is available and will cause a decoder
3200 to be called when specified in the traces. It is an opportunistic decoding.
3201 When the source declares some verbosity levels, these ones are listed with
3202 a description of what they correspond to. In this case the trace decoder
3203 provided by the source will be as accurate as possible based on the
3204 information available at the trace point. The first level above "quiet" is
3205 set by default.
3206
Willy Tarreau2212e6a2015-10-13 14:40:55 +02003207
William Lallemand142db372018-12-11 18:56:45 +010032089.4. Master CLI
3209---------------
3210
3211The master CLI is a socket bound to the master process in master-worker mode.
3212This CLI gives access to the unix socket commands in every running or leaving
3213processes and allows a basic supervision of those processes.
3214
3215The master CLI is configurable only from the haproxy program arguments with
3216the -S option. This option also takes bind options separated by commas.
3217
3218Example:
3219
3220 # haproxy -W -S 127.0.0.1:1234 -f test1.cfg
3221 # haproxy -Ws -S /tmp/master-socket,uid,1000,gid,1000,mode,600 -f test1.cfg
William Lallemandb7ea1412018-12-13 09:05:47 +01003222 # haproxy -W -S /tmp/master-socket,level,user -f test1.cfg
William Lallemand142db372018-12-11 18:56:45 +01003223
3224The master CLI introduces a new 'show proc' command to surpervise the
3225processes:
3226
3227Example:
3228
3229 $ echo 'show proc' | socat /var/run/haproxy-master.sock -
William Lallemand1dc69632019-06-12 19:11:33 +02003230 #<PID> <type> <relative PID> <reloads> <uptime> <version>
3231 1162 master 0 5 0d00h02m07s 2.0-dev7-0124c9-7
William Lallemand142db372018-12-11 18:56:45 +01003232 # workers
William Lallemand1dc69632019-06-12 19:11:33 +02003233 1271 worker 1 0 0d00h00m00s 2.0-dev7-0124c9-7
3234 1272 worker 2 0 0d00h00m00s 2.0-dev7-0124c9-7
William Lallemand142db372018-12-11 18:56:45 +01003235 # old workers
William Lallemand1dc69632019-06-12 19:11:33 +02003236 1233 worker [was: 1] 3 0d00h00m43s 2.0-dev3-6019f6-289
William Lallemand142db372018-12-11 18:56:45 +01003237
3238
3239In this example, the master has been reloaded 5 times but one of the old
3240worker is still running and survived 3 reloads. You could access the CLI of
3241this worker to understand what's going on.
3242
Willy Tarreau52880f92018-12-15 13:30:03 +01003243When the prompt is enabled (via the "prompt" command), the context the CLI is
3244working on is displayed in the prompt. The master is identified by the "master"
3245string, and other processes are identified with their PID. In case the last
3246reload failed, the master prompt will be changed to "master[ReloadFailed]>" so
3247that it becomes visible that the process is still running on the previous
3248configuration and that the new configuration is not operational.
3249
William Lallemand142db372018-12-11 18:56:45 +01003250The master CLI uses a special prefix notation to access the multiple
3251processes. This notation is easily identifiable as it begins by a @.
3252
3253A @ prefix can be followed by a relative process number or by an exclamation
3254point and a PID. (e.g. @1 or @!1271). A @ alone could be use to specify the
3255master. Leaving processes are only accessible with the PID as relative process
3256number are only usable with the current processes.
3257
3258Examples:
3259
3260 $ socat /var/run/haproxy-master.sock readline
3261 prompt
3262 master> @1 show info; @2 show info
3263 [...]
3264 Process_num: 1
3265 Pid: 1271
3266 [...]
3267 Process_num: 2
3268 Pid: 1272
3269 [...]
3270 master>
3271
3272 $ echo '@!1271 show info; @!1272 show info' | socat /var/run/haproxy-master.sock -
3273 [...]
3274
3275A prefix could be use as a command, which will send every next commands to
3276the specified process.
3277
3278Examples:
3279
3280 $ socat /var/run/haproxy-master.sock readline
3281 prompt
3282 master> @1
3283 1271> show info
3284 [...]
3285 1271> show stat
3286 [...]
3287 1271> @
3288 master>
3289
3290 $ echo '@1; show info; show stat; @2; show info; show stat' | socat /var/run/haproxy-master.sock -
3291 [...]
3292
William Lallemanda57b7e32018-12-14 21:11:31 +01003293You can also reload the HAProxy master process with the "reload" command which
3294does the same as a `kill -USR2` on the master process, provided that the user
3295has at least "operator" or "admin" privileges.
3296
3297Example:
3298
3299 $ echo "reload" | socat /var/run/haproxy-master.sock
3300
3301Note that a reload will close the connection to the master CLI.
3302
William Lallemand142db372018-12-11 18:56:45 +01003303
Willy Tarreau2212e6a2015-10-13 14:40:55 +0200330410. Tricks for easier configuration management
3305----------------------------------------------
3306
3307It is very common that two HAProxy nodes constituting a cluster share exactly
3308the same configuration modulo a few addresses. Instead of having to maintain a
3309duplicate configuration for each node, which will inevitably diverge, it is
3310possible to include environment variables in the configuration. Thus multiple
3311configuration may share the exact same file with only a few different system
3312wide environment variables. This started in version 1.5 where only addresses
3313were allowed to include environment variables, and 1.6 goes further by
3314supporting environment variables everywhere. The syntax is the same as in the
3315UNIX shell, a variable starts with a dollar sign ('$'), followed by an opening
3316curly brace ('{'), then the variable name followed by the closing brace ('}').
3317Except for addresses, environment variables are only interpreted in arguments
3318surrounded with double quotes (this was necessary not to break existing setups
3319using regular expressions involving the dollar symbol).
3320
3321Environment variables also make it convenient to write configurations which are
3322expected to work on various sites where only the address changes. It can also
3323permit to remove passwords from some configs. Example below where the the file
3324"site1.env" file is sourced by the init script upon startup :
3325
3326 $ cat site1.env
3327 LISTEN=192.168.1.1
3328 CACHE_PFX=192.168.11
3329 SERVER_PFX=192.168.22
3330 LOGGER=192.168.33.1
3331 STATSLP=admin:pa$$w0rd
3332 ABUSERS=/etc/haproxy/abuse.lst
3333 TIMEOUT=10s
3334
3335 $ cat haproxy.cfg
3336 global
3337 log "${LOGGER}:514" local0
3338
3339 defaults
3340 mode http
3341 timeout client "${TIMEOUT}"
3342 timeout server "${TIMEOUT}"
3343 timeout connect 5s
3344
3345 frontend public
3346 bind "${LISTEN}:80"
3347 http-request reject if { src -f "${ABUSERS}" }
3348 stats uri /stats
3349 stats auth "${STATSLP}"
3350 use_backend cache if { path_end .jpg .css .ico }
3351 default_backend server
3352
3353 backend cache
3354 server cache1 "${CACHE_PFX}.1:18080" check
3355 server cache2 "${CACHE_PFX}.2:18080" check
3356
3357 backend server
3358 server cache1 "${SERVER_PFX}.1:8080" check
3359 server cache2 "${SERVER_PFX}.2:8080" check
3360
3361
336211. Well-known traps to avoid
3363-----------------------------
3364
3365Once in a while, someone reports that after a system reboot, the haproxy
3366service wasn't started, and that once they start it by hand it works. Most
3367often, these people are running a clustered IP address mechanism such as
3368keepalived, to assign the service IP address to the master node only, and while
3369it used to work when they used to bind haproxy to address 0.0.0.0, it stopped
3370working after they bound it to the virtual IP address. What happens here is
3371that when the service starts, the virtual IP address is not yet owned by the
3372local node, so when HAProxy wants to bind to it, the system rejects this
3373because it is not a local IP address. The fix doesn't consist in delaying the
3374haproxy service startup (since it wouldn't stand a restart), but instead to
3375properly configure the system to allow binding to non-local addresses. This is
3376easily done on Linux by setting the net.ipv4.ip_nonlocal_bind sysctl to 1. This
3377is also needed in order to transparently intercept the IP traffic that passes
3378through HAProxy for a specific target address.
3379
3380Multi-process configurations involving source port ranges may apparently seem
3381to work but they will cause some random failures under high loads because more
3382than one process may try to use the same source port to connect to the same
3383server, which is not possible. The system will report an error and a retry will
3384happen, picking another port. A high value in the "retries" parameter may hide
3385the effect to a certain extent but this also comes with increased CPU usage and
3386processing time. Logs will also report a certain number of retries. For this
3387reason, port ranges should be avoided in multi-process configurations.
3388
Dan Lloyd8e48b872016-07-01 21:01:18 -04003389Since HAProxy uses SO_REUSEPORT and supports having multiple independent
Willy Tarreau2212e6a2015-10-13 14:40:55 +02003390processes bound to the same IP:port, during troubleshooting it can happen that
3391an old process was not stopped before a new one was started. This provides
3392absurd test results which tend to indicate that any change to the configuration
3393is ignored. The reason is that in fact even the new process is restarted with a
3394new configuration, the old one also gets some incoming connections and
3395processes them, returning unexpected results. When in doubt, just stop the new
3396process and try again. If it still works, it very likely means that an old
3397process remains alive and has to be stopped. Linux's "netstat -lntp" is of good
3398help here.
3399
3400When adding entries to an ACL from the command line (eg: when blacklisting a
3401source address), it is important to keep in mind that these entries are not
3402synchronized to the file and that if someone reloads the configuration, these
3403updates will be lost. While this is often the desired effect (for blacklisting)
3404it may not necessarily match expectations when the change was made as a fix for
3405a problem. See the "add acl" action of the CLI interface.
3406
3407
340812. Debugging and performance issues
3409------------------------------------
3410
3411When HAProxy is started with the "-d" option, it will stay in the foreground
3412and will print one line per event, such as an incoming connection, the end of a
3413connection, and for each request or response header line seen. This debug
3414output is emitted before the contents are processed, so they don't consider the
3415local modifications. The main use is to show the request and response without
3416having to run a network sniffer. The output is less readable when multiple
3417connections are handled in parallel, though the "debug2ansi" and "debug2html"
3418scripts found in the examples/ directory definitely help here by coloring the
3419output.
3420
3421If a request or response is rejected because HAProxy finds it is malformed, the
3422best thing to do is to connect to the CLI and issue "show errors", which will
3423report the last captured faulty request and response for each frontend and
3424backend, with all the necessary information to indicate precisely the first
3425character of the input stream that was rejected. This is sometimes needed to
3426prove to customers or to developers that a bug is present in their code. In
3427this case it is often possible to relax the checks (but still keep the
3428captures) using "option accept-invalid-http-request" or its equivalent for
3429responses coming from the server "option accept-invalid-http-response". Please
3430see the configuration manual for more details.
3431
3432Example :
3433
3434 > show errors
3435 Total events captured on [13/Oct/2015:13:43:47.169] : 1
3436
3437 [13/Oct/2015:13:43:40.918] frontend HAProxyLocalStats (#2): invalid request
3438 backend <NONE> (#-1), server <NONE> (#-1), event #0
3439 src 127.0.0.1:51981, session #0, session flags 0x00000080
3440 HTTP msg state 26, msg flags 0x00000000, tx flags 0x00000000
3441 HTTP chunk len 0 bytes, HTTP body len 0 bytes
3442 buffer flags 0x00808002, out 0 bytes, total 31 bytes
3443 pending 31 bytes, wrapping at 8040, error at position 13:
3444
3445 00000 GET /invalid request HTTP/1.1\r\n
3446
3447
3448The output of "show info" on the CLI provides a number of useful information
3449regarding the maximum connection rate ever reached, maximum SSL key rate ever
3450reached, and in general all information which can help to explain temporary
3451issues regarding CPU or memory usage. Example :
3452
3453 > show info
3454 Name: HAProxy
3455 Version: 1.6-dev7-e32d18-17
3456 Release_date: 2015/10/12
3457 Nbproc: 1
3458 Process_num: 1
3459 Pid: 7949
3460 Uptime: 0d 0h02m39s
3461 Uptime_sec: 159
3462 Memmax_MB: 0
3463 Ulimit-n: 120032
3464 Maxsock: 120032
3465 Maxconn: 60000
3466 Hard_maxconn: 60000
3467 CurrConns: 0
3468 CumConns: 3
3469 CumReq: 3
3470 MaxSslConns: 0
3471 CurrSslConns: 0
3472 CumSslConns: 0
3473 Maxpipes: 0
3474 PipesUsed: 0
3475 PipesFree: 0
3476 ConnRate: 0
3477 ConnRateLimit: 0
3478 MaxConnRate: 1
3479 SessRate: 0
3480 SessRateLimit: 0
3481 MaxSessRate: 1
3482 SslRate: 0
3483 SslRateLimit: 0
3484 MaxSslRate: 0
3485 SslFrontendKeyRate: 0
3486 SslFrontendMaxKeyRate: 0
3487 SslFrontendSessionReuse_pct: 0
3488 SslBackendKeyRate: 0
3489 SslBackendMaxKeyRate: 0
3490 SslCacheLookups: 0
3491 SslCacheMisses: 0
3492 CompressBpsIn: 0
3493 CompressBpsOut: 0
3494 CompressBpsRateLim: 0
3495 ZlibMemUsage: 0
3496 MaxZlibMemUsage: 0
3497 Tasks: 5
3498 Run_queue: 1
3499 Idle_pct: 100
3500 node: wtap
3501 description:
3502
3503When an issue seems to randomly appear on a new version of HAProxy (eg: every
3504second request is aborted, occasional crash, etc), it is worth trying to enable
Dan Lloyd8e48b872016-07-01 21:01:18 -04003505memory poisoning so that each call to malloc() is immediately followed by the
Willy Tarreau2212e6a2015-10-13 14:40:55 +02003506filling of the memory area with a configurable byte. By default this byte is
35070x50 (ASCII for 'P'), but any other byte can be used, including zero (which
3508will have the same effect as a calloc() and which may make issues disappear).
Dan Lloyd8e48b872016-07-01 21:01:18 -04003509Memory poisoning is enabled on the command line using the "-dM" option. It
Willy Tarreau2212e6a2015-10-13 14:40:55 +02003510slightly hurts performance and is not recommended for use in production. If
Dan Lloyd8e48b872016-07-01 21:01:18 -04003511an issue happens all the time with it or never happens when poisoning uses
Willy Tarreau2212e6a2015-10-13 14:40:55 +02003512byte zero, it clearly means you've found a bug and you definitely need to
3513report it. Otherwise if there's no clear change, the problem it is not related.
3514
3515When debugging some latency issues, it is important to use both strace and
3516tcpdump on the local machine, and another tcpdump on the remote system. The
3517reason for this is that there are delays everywhere in the processing chain and
3518it is important to know which one is causing latency to know where to act. In
3519practice, the local tcpdump will indicate when the input data come in. Strace
3520will indicate when haproxy receives these data (using recv/recvfrom). Warning,
3521openssl uses read()/write() syscalls instead of recv()/send(). Strace will also
3522show when haproxy sends the data, and tcpdump will show when the system sends
3523these data to the interface. Then the external tcpdump will show when the data
3524sent are really received (since the local one only shows when the packets are
3525queued). The benefit of sniffing on the local system is that strace and tcpdump
3526will use the same reference clock. Strace should be used with "-tts200" to get
3527complete timestamps and report large enough chunks of data to read them.
3528Tcpdump should be used with "-nvvttSs0" to report full packets, real sequence
3529numbers and complete timestamps.
3530
3531In practice, received data are almost always immediately received by haproxy
3532(unless the machine has a saturated CPU or these data are invalid and not
3533delivered). If these data are received but not sent, it generally is because
3534the output buffer is saturated (ie: recipient doesn't consume the data fast
3535enough). This can be confirmed by seeing that the polling doesn't notify of
3536the ability to write on the output file descriptor for some time (it's often
3537easier to spot in the strace output when the data finally leave and then roll
3538back to see when the write event was notified). It generally matches an ACK
3539received from the recipient, and detected by tcpdump. Once the data are sent,
3540they may spend some time in the system doing nothing. Here again, the TCP
3541congestion window may be limited and not allow these data to leave, waiting for
3542an ACK to open the window. If the traffic is idle and the data take 40 ms or
3543200 ms to leave, it's a different issue (which is not an issue), it's the fact
3544that the Nagle algorithm prevents empty packets from leaving immediately, in
3545hope that they will be merged with subsequent data. HAProxy automatically
3546disables Nagle in pure TCP mode and in tunnels. However it definitely remains
3547enabled when forwarding an HTTP body (and this contributes to the performance
3548improvement there by reducing the number of packets). Some HTTP non-compliant
3549applications may be sensitive to the latency when delivering incomplete HTTP
3550response messages. In this case you will have to enable "option http-no-delay"
3551to disable Nagle in order to work around their design, keeping in mind that any
3552other proxy in the chain may similarly be impacted. If tcpdump reports that data
3553leave immediately but the other end doesn't see them quickly, it can mean there
Dan Lloyd8e48b872016-07-01 21:01:18 -04003554is a congested WAN link, a congested LAN with flow control enabled and
Willy Tarreau2212e6a2015-10-13 14:40:55 +02003555preventing the data from leaving, or more commonly that HAProxy is in fact
3556running in a virtual machine and that for whatever reason the hypervisor has
3557decided that the data didn't need to be sent immediately. In virtualized
3558environments, latency issues are almost always caused by the virtualization
3559layer, so in order to save time, it's worth first comparing tcpdump in the VM
3560and on the external components. Any difference has to be credited to the
3561hypervisor and its accompanying drivers.
3562
3563When some TCP SACK segments are seen in tcpdump traces (using -vv), it always
3564means that the side sending them has got the proof of a lost packet. While not
3565seeing them doesn't mean there are no losses, seeing them definitely means the
3566network is lossy. Losses are normal on a network, but at a rate where SACKs are
3567not noticeable at the naked eye. If they appear a lot in the traces, it is
3568worth investigating exactly what happens and where the packets are lost. HTTP
3569doesn't cope well with TCP losses, which introduce huge latencies.
3570
3571The "netstat -i" command will report statistics per interface. An interface
3572where the Rx-Ovr counter grows indicates that the system doesn't have enough
3573resources to receive all incoming packets and that they're lost before being
3574processed by the network driver. Rx-Drp indicates that some received packets
3575were lost in the network stack because the application doesn't process them
3576fast enough. This can happen during some attacks as well. Tx-Drp means that
3577the output queues were full and packets had to be dropped. When using TCP it
Dan Lloyd8e48b872016-07-01 21:01:18 -04003578should be very rare, but will possibly indicate a saturated outgoing link.
Willy Tarreau2212e6a2015-10-13 14:40:55 +02003579
3580
358113. Security considerations
3582---------------------------
3583
3584HAProxy is designed to run with very limited privileges. The standard way to
3585use it is to isolate it into a chroot jail and to drop its privileges to a
3586non-root user without any permissions inside this jail so that if any future
3587vulnerability were to be discovered, its compromise would not affect the rest
3588of the system.
3589
Dan Lloyd8e48b872016-07-01 21:01:18 -04003590In order to perform a chroot, it first needs to be started as a root user. It is
Willy Tarreau2212e6a2015-10-13 14:40:55 +02003591pointless to build hand-made chroots to start the process there, these ones are
3592painful to build, are never properly maintained and always contain way more
3593bugs than the main file-system. And in case of compromise, the intruder can use
3594the purposely built file-system. Unfortunately many administrators confuse
3595"start as root" and "run as root", resulting in the uid change to be done prior
3596to starting haproxy, and reducing the effective security restrictions.
3597
3598HAProxy will need to be started as root in order to :
3599 - adjust the file descriptor limits
3600 - bind to privileged port numbers
3601 - bind to a specific network interface
3602 - transparently listen to a foreign address
3603 - isolate itself inside the chroot jail
3604 - drop to another non-privileged UID
3605
3606HAProxy may require to be run as root in order to :
3607 - bind to an interface for outgoing connections
3608 - bind to privileged source ports for outgoing connections
Dan Lloyd8e48b872016-07-01 21:01:18 -04003609 - transparently bind to a foreign address for outgoing connections
Willy Tarreau2212e6a2015-10-13 14:40:55 +02003610
3611Most users will never need the "run as root" case. But the "start as root"
3612covers most usages.
3613
3614A safe configuration will have :
3615
3616 - a chroot statement pointing to an empty location without any access
3617 permissions. This can be prepared this way on the UNIX command line :
3618
3619 # mkdir /var/empty && chmod 0 /var/empty || echo "Failed"
3620
3621 and referenced like this in the HAProxy configuration's global section :
3622
3623 chroot /var/empty
3624
3625 - both a uid/user and gid/group statements in the global section :
3626
3627 user haproxy
3628 group haproxy
3629
3630 - a stats socket whose mode, uid and gid are set to match the user and/or
3631 group allowed to access the CLI so that nobody may access it :
3632
3633 stats socket /var/run/haproxy.stat uid hatop gid hatop mode 600
3634