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Willy Tarreau2212e6a2015-10-13 14:40:55 +02001 ------------------------
2 HAProxy Management Guide
3 ------------------------
Willy Tarreau9dc6b972019-06-16 21:49:47 +02004 version 2.1
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
196 error is encountered.
197
198 -d : enable debug mode. This disables daemon mode, forces the process to stay
199 in foreground and to show incoming and outgoing events. It is equivalent to
200 the "global" section's "debug" keyword. It must never be used in an init
201 script.
202
203 -dG : disable use of getaddrinfo() to resolve host names into addresses. It
204 can be used when suspecting that getaddrinfo() doesn't work as expected.
205 This option was made available because many bogus implementations of
206 getaddrinfo() exist on various systems and cause anomalies that are
207 difficult to troubleshoot.
208
Dan Lloyd8e48b872016-07-01 21:01:18 -0400209 -dM[<byte>] : forces memory poisoning, which means that each and every
Willy Tarreaubafbe012017-11-24 17:34:44 +0100210 memory region allocated with malloc() or pool_alloc() will be filled with
Willy Tarreau2212e6a2015-10-13 14:40:55 +0200211 <byte> before being passed to the caller. When <byte> is not specified, it
212 defaults to 0x50 ('P'). While this slightly slows down operations, it is
213 useful to reliably trigger issues resulting from missing initializations in
214 the code that cause random crashes. Note that -dM0 has the effect of
215 turning any malloc() into a calloc(). In any case if a bug appears or
216 disappears when using this option it means there is a bug in haproxy, so
217 please report it.
218
219 -dS : disable use of the splice() system call. It is equivalent to the
220 "global" section's "nosplice" keyword. This may be used when splice() is
221 suspected to behave improperly or to cause performance issues, or when
222 using strace to see the forwarded data (which do not appear when using
223 splice()).
224
225 -dV : disable SSL verify on the server side. It is equivalent to having
226 "ssl-server-verify none" in the "global" section. This is useful when
227 trying to reproduce production issues out of the production
228 environment. Never use this in an init script as it degrades SSL security
229 to the servers.
230
231 -db : disable background mode and multi-process mode. The process remains in
232 foreground. It is mainly used during development or during small tests, as
233 Ctrl-C is enough to stop the process. Never use it in an init script.
234
235 -de : disable the use of the "epoll" poller. It is equivalent to the "global"
236 section's keyword "noepoll". It is mostly useful when suspecting a bug
237 related to this poller. On systems supporting epoll, the fallback will
238 generally be the "poll" poller.
239
240 -dk : disable the use of the "kqueue" poller. It is equivalent to the
241 "global" section's keyword "nokqueue". It is mostly useful when suspecting
242 a bug related to this poller. On systems supporting kqueue, the fallback
243 will generally be the "poll" poller.
244
245 -dp : disable the use of the "poll" poller. It is equivalent to the "global"
246 section's keyword "nopoll". It is mostly useful when suspecting a bug
247 related to this poller. On systems supporting poll, the fallback will
248 generally be the "select" poller, which cannot be disabled and is limited
249 to 1024 file descriptors.
250
Willy Tarreau3eed10e2016-11-07 21:03:16 +0100251 -dr : ignore server address resolution failures. It is very common when
252 validating a configuration out of production not to have access to the same
253 resolvers and to fail on server address resolution, making it difficult to
254 test a configuration. This option simply appends the "none" method to the
255 list of address resolution methods for all servers, ensuring that even if
256 the libc fails to resolve an address, the startup sequence is not
257 interrupted.
258
Willy Tarreau70060452015-12-14 12:46:07 +0100259 -m <limit> : limit the total allocatable memory to <limit> megabytes across
260 all processes. This may cause some connection refusals or some slowdowns
Willy Tarreau2212e6a2015-10-13 14:40:55 +0200261 depending on the amount of memory needed for normal operations. This is
Willy Tarreau70060452015-12-14 12:46:07 +0100262 mostly used to force the processes to work in a constrained resource usage
263 scenario. It is important to note that the memory is not shared between
264 processes, so in a multi-process scenario, this value is first divided by
265 global.nbproc before forking.
Willy Tarreau2212e6a2015-10-13 14:40:55 +0200266
267 -n <limit> : limits the per-process connection limit to <limit>. This is
268 equivalent to the global section's keyword "maxconn". It has precedence
269 over this keyword. This may be used to quickly force lower limits to avoid
270 a service outage on systems where resource limits are too low.
271
272 -p <file> : write all processes' pids into <file> during startup. This is
273 equivalent to the "global" section's keyword "pidfile". The file is opened
274 before entering the chroot jail, and after doing the chdir() implied by
275 "-C". Each pid appears on its own line.
276
277 -q : set "quiet" mode. This disables some messages during the configuration
278 parsing and during startup. It can be used in combination with "-c" to
279 just check if a configuration file is valid or not.
280
William Lallemand142db372018-12-11 18:56:45 +0100281 -S <bind>[,bind_options...]: in master-worker mode, bind a master CLI, which
282 allows the access to every processes, running or leaving ones.
283 For security reasons, it is recommended to bind the master CLI to a local
284 UNIX socket. The bind options are the same as the keyword "bind" in
285 the configuration file with words separated by commas instead of spaces.
286
287 Note that this socket can't be used to retrieve the listening sockets from
288 an old process during a seamless reload.
289
Willy Tarreau2212e6a2015-10-13 14:40:55 +0200290 -sf <pid>* : send the "finish" signal (SIGUSR1) to older processes after boot
291 completion to ask them to finish what they are doing and to leave. <pid>
292 is a list of pids to signal (one per argument). The list ends on any
293 option starting with a "-". It is not a problem if the list of pids is
294 empty, so that it can be built on the fly based on the result of a command
295 like "pidof" or "pgrep".
296
297 -st <pid>* : send the "terminate" signal (SIGTERM) to older processes after
298 boot completion to terminate them immediately without finishing what they
299 were doing. <pid> is a list of pids to signal (one per argument). The list
300 is ends on any option starting with a "-". It is not a problem if the list
301 of pids is empty, so that it can be built on the fly based on the result of
302 a command like "pidof" or "pgrep".
303
304 -v : report the version and build date.
305
306 -vv : display the version, build options, libraries versions and usable
307 pollers. This output is systematically requested when filing a bug report.
308
Olivier Houchardd33fc3a2017-04-05 22:50:59 +0200309 -x <unix_socket> : connect to the specified socket and try to retrieve any
310 listening sockets from the old process, and use them instead of trying to
311 bind new ones. This is useful to avoid missing any new connection when
William Lallemandf6975e92017-05-26 17:42:10 +0200312 reloading the configuration on Linux. The capability must be enable on the
313 stats socket using "expose-fd listeners" in your configuration.
Olivier Houchardd33fc3a2017-04-05 22:50:59 +0200314
Dan Lloyd8e48b872016-07-01 21:01:18 -0400315A safe way to start HAProxy from an init file consists in forcing the daemon
Willy Tarreau2212e6a2015-10-13 14:40:55 +0200316mode, storing existing pids to a pid file and using this pid file to notify
317older processes to finish before leaving :
318
319 haproxy -f /etc/haproxy.cfg \
320 -D -p /var/run/haproxy.pid -sf $(cat /var/run/haproxy.pid)
321
322When the configuration is split into a few specific files (eg: tcp vs http),
323it is recommended to use the "-f" option :
324
325 haproxy -f /etc/haproxy/global.cfg -f /etc/haproxy/stats.cfg \
326 -f /etc/haproxy/default-tcp.cfg -f /etc/haproxy/tcp.cfg \
327 -f /etc/haproxy/default-http.cfg -f /etc/haproxy/http.cfg \
328 -D -p /var/run/haproxy.pid -sf $(cat /var/run/haproxy.pid)
329
330When an unknown number of files is expected, such as customer-specific files,
331it is recommended to assign them a name starting with a fixed-size sequence
332number and to use "--" to load them, possibly after loading some defaults :
333
334 haproxy -f /etc/haproxy/global.cfg -f /etc/haproxy/stats.cfg \
335 -f /etc/haproxy/default-tcp.cfg -f /etc/haproxy/tcp.cfg \
336 -f /etc/haproxy/default-http.cfg -f /etc/haproxy/http.cfg \
337 -D -p /var/run/haproxy.pid -sf $(cat /var/run/haproxy.pid) \
338 -f /etc/haproxy/default-customers.cfg -- /etc/haproxy/customers/*
339
340Sometimes a failure to start may happen for whatever reason. Then it is
341important to verify if the version of HAProxy you are invoking is the expected
342version and if it supports the features you are expecting (eg: SSL, PCRE,
343compression, Lua, etc). This can be verified using "haproxy -vv". Some
344important information such as certain build options, the target system and
345the versions of the libraries being used are reported there. It is also what
346you will systematically be asked for when posting a bug report :
347
348 $ haproxy -vv
349 HA-Proxy version 1.6-dev7-a088d3-4 2015/10/08
350 Copyright 2000-2015 Willy Tarreau <willy@haproxy.org>
351
352 Build options :
353 TARGET = linux2628
354 CPU = generic
355 CC = gcc
356 CFLAGS = -pg -O0 -g -fno-strict-aliasing -Wdeclaration-after-statement \
357 -DBUFSIZE=8030 -DMAXREWRITE=1030 -DSO_MARK=36 -DTCP_REPAIR=19
358 OPTIONS = USE_ZLIB=1 USE_DLMALLOC=1 USE_OPENSSL=1 USE_LUA=1 USE_PCRE=1
359
360 Default settings :
361 maxconn = 2000, bufsize = 8030, maxrewrite = 1030, maxpollevents = 200
362
363 Encrypted password support via crypt(3): yes
364 Built with zlib version : 1.2.6
365 Compression algorithms supported : identity("identity"), deflate("deflate"), \
366 raw-deflate("deflate"), gzip("gzip")
367 Built with OpenSSL version : OpenSSL 1.0.1o 12 Jun 2015
368 Running on OpenSSL version : OpenSSL 1.0.1o 12 Jun 2015
369 OpenSSL library supports TLS extensions : yes
370 OpenSSL library supports SNI : yes
371 OpenSSL library supports prefer-server-ciphers : yes
372 Built with PCRE version : 8.12 2011-01-15
373 PCRE library supports JIT : no (USE_PCRE_JIT not set)
374 Built with Lua version : Lua 5.3.1
375 Built with transparent proxy support using: IP_TRANSPARENT IP_FREEBIND
376
377 Available polling systems :
378 epoll : pref=300, test result OK
379 poll : pref=200, test result OK
380 select : pref=150, test result OK
381 Total: 3 (3 usable), will use epoll.
382
383The relevant information that many non-developer users can verify here are :
384 - the version : 1.6-dev7-a088d3-4 above means the code is currently at commit
385 ID "a088d3" which is the 4th one after after official version "1.6-dev7".
386 Version 1.6-dev7 would show as "1.6-dev7-8c1ad7". What matters here is in
387 fact "1.6-dev7". This is the 7th development version of what will become
388 version 1.6 in the future. A development version not suitable for use in
389 production (unless you know exactly what you are doing). A stable version
390 will show as a 3-numbers version, such as "1.5.14-16f863", indicating the
391 14th level of fix on top of version 1.5. This is a production-ready version.
392
393 - the release date : 2015/10/08. It is represented in the universal
394 year/month/day format. Here this means August 8th, 2015. Given that stable
395 releases are issued every few months (1-2 months at the beginning, sometimes
396 6 months once the product becomes very stable), if you're seeing an old date
397 here, it means you're probably affected by a number of bugs or security
398 issues that have since been fixed and that it might be worth checking on the
399 official site.
400
401 - build options : they are relevant to people who build their packages
402 themselves, they can explain why things are not behaving as expected. For
403 example the development version above was built for Linux 2.6.28 or later,
Dan Lloyd8e48b872016-07-01 21:01:18 -0400404 targeting a generic CPU (no CPU-specific optimizations), and lacks any
Willy Tarreau2212e6a2015-10-13 14:40:55 +0200405 code optimization (-O0) so it will perform poorly in terms of performance.
406
407 - libraries versions : zlib version is reported as found in the library
408 itself. In general zlib is considered a very stable product and upgrades
409 are almost never needed. OpenSSL reports two versions, the version used at
410 build time and the one being used, as found on the system. These ones may
411 differ by the last letter but never by the numbers. The build date is also
412 reported because most OpenSSL bugs are security issues and need to be taken
413 seriously, so this library absolutely needs to be kept up to date. Seeing a
414 4-months old version here is highly suspicious and indeed an update was
415 missed. PCRE provides very fast regular expressions and is highly
416 recommended. Certain of its extensions such as JIT are not present in all
417 versions and still young so some people prefer not to build with them,
Dan Lloyd8e48b872016-07-01 21:01:18 -0400418 which is why the build status is reported as well. Regarding the Lua
Willy Tarreau2212e6a2015-10-13 14:40:55 +0200419 scripting language, HAProxy expects version 5.3 which is very young since
420 it was released a little time before HAProxy 1.6. It is important to check
421 on the Lua web site if some fixes are proposed for this branch.
422
423 - Available polling systems will affect the process's scalability when
424 dealing with more than about one thousand of concurrent connections. These
425 ones are only available when the correct system was indicated in the TARGET
426 variable during the build. The "epoll" mechanism is highly recommended on
427 Linux, and the kqueue mechanism is highly recommended on BSD. Lacking them
428 will result in poll() or even select() being used, causing a high CPU usage
429 when dealing with a lot of connections.
430
431
4324. Stopping and restarting HAProxy
433----------------------------------
434
435HAProxy supports a graceful and a hard stop. The hard stop is simple, when the
436SIGTERM signal is sent to the haproxy process, it immediately quits and all
437established connections are closed. The graceful stop is triggered when the
438SIGUSR1 signal is sent to the haproxy process. It consists in only unbinding
439from listening ports, but continue to process existing connections until they
440close. Once the last connection is closed, the process leaves.
441
442The hard stop method is used for the "stop" or "restart" actions of the service
443management script. The graceful stop is used for the "reload" action which
444tries to seamlessly reload a new configuration in a new process.
445
446Both of these signals may be sent by the new haproxy process itself during a
447reload or restart, so that they are sent at the latest possible moment and only
448if absolutely required. This is what is performed by the "-st" (hard) and "-sf"
449(graceful) options respectively.
450
William Lallemande202b1e2017-06-01 17:38:56 +0200451In master-worker mode, it is not needed to start a new haproxy process in
452order to reload the configuration. The master process reacts to the SIGUSR2
453signal by reexecuting itself with the -sf parameter followed by the PIDs of
454the workers. The master will then parse the configuration file and fork new
455workers.
456
Willy Tarreau2212e6a2015-10-13 14:40:55 +0200457To understand better how these signals are used, it is important to understand
458the whole restart mechanism.
459
460First, an existing haproxy process is running. The administrator uses a system
461specific command such as "/etc/init.d/haproxy reload" to indicate he wants to
462take the new configuration file into effect. What happens then is the following.
463First, the service script (/etc/init.d/haproxy or equivalent) will verify that
464the configuration file parses correctly using "haproxy -c". After that it will
465try to start haproxy with this configuration file, using "-st" or "-sf".
466
467Then HAProxy tries to bind to all listening ports. If some fatal errors happen
468(eg: address not present on the system, permission denied), the process quits
469with an error. If a socket binding fails because a port is already in use, then
470the process will first send a SIGTTOU signal to all the pids specified in the
471"-st" or "-sf" pid list. This is what is called the "pause" signal. It instructs
472all existing haproxy processes to temporarily stop listening to their ports so
473that the new process can try to bind again. During this time, the old process
474continues to process existing connections. If the binding still fails (because
475for example a port is shared with another daemon), then the new process sends a
476SIGTTIN signal to the old processes to instruct them to resume operations just
477as if nothing happened. The old processes will then restart listening to the
478ports and continue to accept connections. Not that this mechanism is system
Dan Lloyd8e48b872016-07-01 21:01:18 -0400479dependent and some operating systems may not support it in multi-process mode.
Willy Tarreau2212e6a2015-10-13 14:40:55 +0200480
481If the new process manages to bind correctly to all ports, then it sends either
482the SIGTERM (hard stop in case of "-st") or the SIGUSR1 (graceful stop in case
483of "-sf") to all processes to notify them that it is now in charge of operations
484and that the old processes will have to leave, either immediately or once they
485have finished their job.
486
487It is important to note that during this timeframe, there are two small windows
488of a few milliseconds each where it is possible that a few connection failures
489will be noticed during high loads. Typically observed failure rates are around
4901 failure during a reload operation every 10000 new connections per second,
491which means that a heavily loaded site running at 30000 new connections per
492second may see about 3 failed connection upon every reload. The two situations
493where this happens are :
494
495 - if the new process fails to bind due to the presence of the old process,
496 it will first have to go through the SIGTTOU+SIGTTIN sequence, which
497 typically lasts about one millisecond for a few tens of frontends, and
498 during which some ports will not be bound to the old process and not yet
499 bound to the new one. HAProxy works around this on systems that support the
500 SO_REUSEPORT socket options, as it allows the new process to bind without
501 first asking the old one to unbind. Most BSD systems have been supporting
502 this almost forever. Linux has been supporting this in version 2.0 and
503 dropped it around 2.2, but some patches were floating around by then. It
504 was reintroduced in kernel 3.9, so if you are observing a connection
Dan Lloyd8e48b872016-07-01 21:01:18 -0400505 failure rate above the one mentioned above, please ensure that your kernel
Willy Tarreau2212e6a2015-10-13 14:40:55 +0200506 is 3.9 or newer, or that relevant patches were backported to your kernel
507 (less likely).
508
509 - when the old processes close the listening ports, the kernel may not always
510 redistribute any pending connection that was remaining in the socket's
511 backlog. Under high loads, a SYN packet may happen just before the socket
512 is closed, and will lead to an RST packet being sent to the client. In some
513 critical environments where even one drop is not acceptable, these ones are
514 sometimes dealt with using firewall rules to block SYN packets during the
515 reload, forcing the client to retransmit. This is totally system-dependent,
516 as some systems might be able to visit other listening queues and avoid
517 this RST. A second case concerns the ACK from the client on a local socket
518 that was in SYN_RECV state just before the close. This ACK will lead to an
519 RST packet while the haproxy process is still not aware of it. This one is
Dan Lloyd8e48b872016-07-01 21:01:18 -0400520 harder to get rid of, though the firewall filtering rules mentioned above
Willy Tarreau2212e6a2015-10-13 14:40:55 +0200521 will work well if applied one second or so before restarting the process.
522
523For the vast majority of users, such drops will never ever happen since they
524don't have enough load to trigger the race conditions. And for most high traffic
525users, the failure rate is still fairly within the noise margin provided that at
526least SO_REUSEPORT is properly supported on their systems.
527
528
5295. File-descriptor limitations
530------------------------------
531
532In order to ensure that all incoming connections will successfully be served,
533HAProxy computes at load time the total number of file descriptors that will be
534needed during the process's life. A regular Unix process is generally granted
5351024 file descriptors by default, and a privileged process can raise this limit
536itself. This is one reason for starting HAProxy as root and letting it adjust
537the limit. The default limit of 1024 file descriptors roughly allow about 500
538concurrent connections to be processed. The computation is based on the global
539maxconn parameter which limits the total number of connections per process, the
540number of listeners, the number of servers which have a health check enabled,
541the agent checks, the peers, the loggers and possibly a few other technical
542requirements. A simple rough estimate of this number consists in simply
543doubling the maxconn value and adding a few tens to get the approximate number
544of file descriptors needed.
545
546Originally HAProxy did not know how to compute this value, and it was necessary
547to pass the value using the "ulimit-n" setting in the global section. This
548explains why even today a lot of configurations are seen with this setting
549present. Unfortunately it was often miscalculated resulting in connection
550failures when approaching maxconn instead of throttling incoming connection
551while waiting for the needed resources. For this reason it is important to
Dan Lloyd8e48b872016-07-01 21:01:18 -0400552remove any vestigial "ulimit-n" setting that can remain from very old versions.
Willy Tarreau2212e6a2015-10-13 14:40:55 +0200553
554Raising the number of file descriptors to accept even moderate loads is
555mandatory but comes with some OS-specific adjustments. First, the select()
556polling system is limited to 1024 file descriptors. In fact on Linux it used
557to be capable of handling more but since certain OS ship with excessively
558restrictive SELinux policies forbidding the use of select() with more than
5591024 file descriptors, HAProxy now refuses to start in this case in order to
560avoid any issue at run time. On all supported operating systems, poll() is
561available and will not suffer from this limitation. It is automatically picked
Dan Lloyd8e48b872016-07-01 21:01:18 -0400562so there is nothing to do to get a working configuration. But poll's becomes
Willy Tarreau2212e6a2015-10-13 14:40:55 +0200563very slow when the number of file descriptors increases. While HAProxy does its
564best to limit this performance impact (eg: via the use of the internal file
565descriptor cache and batched processing), a good rule of thumb is that using
566poll() with more than a thousand concurrent connections will use a lot of CPU.
567
568For Linux systems base on kernels 2.6 and above, the epoll() system call will
569be used. It's a much more scalable mechanism relying on callbacks in the kernel
570that guarantee a constant wake up time regardless of the number of registered
571monitored file descriptors. It is automatically used where detected, provided
572that HAProxy had been built for one of the Linux flavors. Its presence and
573support can be verified using "haproxy -vv".
574
575For BSD systems which support it, kqueue() is available as an alternative. It
576is much faster than poll() and even slightly faster than epoll() thanks to its
577batched handling of changes. At least FreeBSD and OpenBSD support it. Just like
578with Linux's epoll(), its support and availability are reported in the output
579of "haproxy -vv".
580
581Having a good poller is one thing, but it is mandatory that the process can
582reach the limits. When HAProxy starts, it immediately sets the new process's
583file descriptor limits and verifies if it succeeds. In case of failure, it
584reports it before forking so that the administrator can see the problem. As
585long as the process is started by as root, there should be no reason for this
586setting to fail. However, it can fail if the process is started by an
587unprivileged user. If there is a compelling reason for *not* starting haproxy
588as root (eg: started by end users, or by a per-application account), then the
589file descriptor limit can be raised by the system administrator for this
590specific user. The effectiveness of the setting can be verified by issuing
591"ulimit -n" from the user's command line. It should reflect the new limit.
592
593Warning: when an unprivileged user's limits are changed in this user's account,
594it is fairly common that these values are only considered when the user logs in
595and not at all in some scripts run at system boot time nor in crontabs. This is
596totally dependent on the operating system, keep in mind to check "ulimit -n"
597before starting haproxy when running this way. The general advice is never to
598start haproxy as an unprivileged user for production purposes. Another good
599reason is that it prevents haproxy from enabling some security protections.
600
601Once it is certain that the system will allow the haproxy process to use the
602requested number of file descriptors, two new system-specific limits may be
603encountered. The first one is the system-wide file descriptor limit, which is
604the total number of file descriptors opened on the system, covering all
605processes. When this limit is reached, accept() or socket() will typically
606return ENFILE. The second one is the per-process hard limit on the number of
607file descriptors, it prevents setrlimit() from being set higher. Both are very
608dependent on the operating system. On Linux, the system limit is set at boot
609based on the amount of memory. It can be changed with the "fs.file-max" sysctl.
610And the per-process hard limit is set to 1048576 by default, but it can be
611changed using the "fs.nr_open" sysctl.
612
613File descriptor limitations may be observed on a running process when they are
614set too low. The strace utility will report that accept() and socket() return
615"-1 EMFILE" when the process's limits have been reached. In this case, simply
616raising the "ulimit-n" value (or removing it) will solve the problem. If these
617system calls return "-1 ENFILE" then it means that the kernel's limits have
618been reached and that something must be done on a system-wide parameter. These
619trouble must absolutely be addressed, as they result in high CPU usage (when
620accept() fails) and failed connections that are generally visible to the user.
621One solution also consists in lowering the global maxconn value to enforce
622serialization, and possibly to disable HTTP keep-alive to force connections
623to be released and reused faster.
624
625
6266. Memory management
627--------------------
628
629HAProxy uses a simple and fast pool-based memory management. Since it relies on
630a small number of different object types, it's much more efficient to pick new
631objects from a pool which already contains objects of the appropriate size than
632to call malloc() for each different size. The pools are organized as a stack or
633LIFO, so that newly allocated objects are taken from recently released objects
634still hot in the CPU caches. Pools of similar sizes are merged together, in
635order to limit memory fragmentation.
636
637By default, since the focus is set on performance, each released object is put
638back into the pool it came from, and allocated objects are never freed since
639they are expected to be reused very soon.
640
641On the CLI, it is possible to check how memory is being used in pools thanks to
642the "show pools" command :
643
644 > show pools
645 Dumping pools usage. Use SIGQUIT to flush them.
Willy Tarreau0a93b642018-10-16 07:58:39 +0200646 - Pool cache_st (16 bytes) : 0 allocated (0 bytes), 0 used, 0 failures, 1 users, @0x9ccc40=03 [SHARED]
647 - Pool pipe (32 bytes) : 5 allocated (160 bytes), 5 used, 0 failures, 2 users, @0x9ccac0=00 [SHARED]
648 - Pool comp_state (48 bytes) : 3 allocated (144 bytes), 3 used, 0 failures, 5 users, @0x9cccc0=04 [SHARED]
649 - Pool filter (64 bytes) : 0 allocated (0 bytes), 0 used, 0 failures, 3 users, @0x9ccbc0=02 [SHARED]
650 - Pool vars (80 bytes) : 0 allocated (0 bytes), 0 used, 0 failures, 2 users, @0x9ccb40=01 [SHARED]
651 - Pool uniqueid (128 bytes) : 0 allocated (0 bytes), 0 used, 0 failures, 2 users, @0x9cd240=15 [SHARED]
652 - Pool task (144 bytes) : 55 allocated (7920 bytes), 55 used, 0 failures, 1 users, @0x9cd040=11 [SHARED]
653 - Pool session (160 bytes) : 1 allocated (160 bytes), 1 used, 0 failures, 1 users, @0x9cd140=13 [SHARED]
654 - Pool h2s (208 bytes) : 0 allocated (0 bytes), 0 used, 0 failures, 2 users, @0x9ccec0=08 [SHARED]
655 - Pool h2c (288 bytes) : 0 allocated (0 bytes), 0 used, 0 failures, 1 users, @0x9cce40=07 [SHARED]
656 - Pool spoe_ctx (304 bytes) : 0 allocated (0 bytes), 0 used, 0 failures, 2 users, @0x9ccf40=09 [SHARED]
657 - Pool connection (400 bytes) : 2 allocated (800 bytes), 2 used, 0 failures, 1 users, @0x9cd1c0=14 [SHARED]
658 - Pool hdr_idx (416 bytes) : 0 allocated (0 bytes), 0 used, 0 failures, 1 users, @0x9cd340=17 [SHARED]
659 - Pool dns_resolut (480 bytes) : 0 allocated (0 bytes), 0 used, 0 failures, 1 users, @0x9ccdc0=06 [SHARED]
660 - Pool dns_answer_ (576 bytes) : 0 allocated (0 bytes), 0 used, 0 failures, 1 users, @0x9ccd40=05 [SHARED]
661 - Pool stream (960 bytes) : 1 allocated (960 bytes), 1 used, 0 failures, 1 users, @0x9cd0c0=12 [SHARED]
662 - Pool requri (1024 bytes) : 0 allocated (0 bytes), 0 used, 0 failures, 1 users, @0x9cd2c0=16 [SHARED]
663 - Pool buffer (8030 bytes) : 3 allocated (24090 bytes), 2 used, 0 failures, 1 users, @0x9cd3c0=18 [SHARED]
664 - Pool trash (8062 bytes) : 1 allocated (8062 bytes), 1 used, 0 failures, 1 users, @0x9cd440=19
665 Total: 19 pools, 42296 bytes allocated, 34266 used.
Willy Tarreau2212e6a2015-10-13 14:40:55 +0200666
667The pool name is only indicative, it's the name of the first object type using
668this pool. The size in parenthesis is the object size for objects in this pool.
669Object sizes are always rounded up to the closest multiple of 16 bytes. The
670number of objects currently allocated and the equivalent number of bytes is
671reported so that it is easy to know which pool is responsible for the highest
672memory usage. The number of objects currently in use is reported as well in the
673"used" field. The difference between "allocated" and "used" corresponds to the
Willy Tarreau0a93b642018-10-16 07:58:39 +0200674objects that have been freed and are available for immediate use. The address
675at the end of the line is the pool's address, and the following number is the
676pool index when it exists, or is reported as -1 if no index was assigned.
Willy Tarreau2212e6a2015-10-13 14:40:55 +0200677
678It is possible to limit the amount of memory allocated per process using the
679"-m" command line option, followed by a number of megabytes. It covers all of
680the process's addressable space, so that includes memory used by some libraries
681as well as the stack, but it is a reliable limit when building a resource
682constrained system. It works the same way as "ulimit -v" on systems which have
683it, or "ulimit -d" for the other ones.
684
685If a memory allocation fails due to the memory limit being reached or because
686the system doesn't have any enough memory, then haproxy will first start to
687free all available objects from all pools before attempting to allocate memory
688again. This mechanism of releasing unused memory can be triggered by sending
689the signal SIGQUIT to the haproxy process. When doing so, the pools state prior
690to the flush will also be reported to stderr when the process runs in
691foreground.
692
693During a reload operation, the process switched to the graceful stop state also
694automatically performs some flushes after releasing any connection so that all
695possible memory is released to save it for the new process.
696
697
6987. CPU usage
699------------
700
701HAProxy normally spends most of its time in the system and a smaller part in
702userland. A finely tuned 3.5 GHz CPU can sustain a rate about 80000 end-to-end
703connection setups and closes per second at 100% CPU on a single core. When one
704core is saturated, typical figures are :
705 - 95% system, 5% user for long TCP connections or large HTTP objects
706 - 85% system and 15% user for short TCP connections or small HTTP objects in
707 close mode
708 - 70% system and 30% user for small HTTP objects in keep-alive mode
709
710The amount of rules processing and regular expressions will increase the user
711land part. The presence of firewall rules, connection tracking, complex routing
712tables in the system will instead increase the system part.
713
714On most systems, the CPU time observed during network transfers can be cut in 4
715parts :
716 - the interrupt part, which concerns all the processing performed upon I/O
717 receipt, before the target process is even known. Typically Rx packets are
718 accounted for in interrupt. On some systems such as Linux where interrupt
719 processing may be deferred to a dedicated thread, it can appear as softirq,
720 and the thread is called ksoftirqd/0 (for CPU 0). The CPU taking care of
721 this load is generally defined by the hardware settings, though in the case
722 of softirq it is often possible to remap the processing to another CPU.
723 This interrupt part will often be perceived as parasitic since it's not
724 associated with any process, but it actually is some processing being done
725 to prepare the work for the process.
726
727 - the system part, which concerns all the processing done using kernel code
728 called from userland. System calls are accounted as system for example. All
729 synchronously delivered Tx packets will be accounted for as system time. If
730 some packets have to be deferred due to queues filling up, they may then be
731 processed in interrupt context later (eg: upon receipt of an ACK opening a
732 TCP window).
733
734 - the user part, which exclusively runs application code in userland. HAProxy
735 runs exclusively in this part, though it makes heavy use of system calls.
736 Rules processing, regular expressions, compression, encryption all add to
737 the user portion of CPU consumption.
738
739 - the idle part, which is what the CPU does when there is nothing to do. For
740 example HAProxy waits for an incoming connection, or waits for some data to
741 leave, meaning the system is waiting for an ACK from the client to push
742 these data.
743
744In practice regarding HAProxy's activity, it is in general reasonably accurate
745(but totally inexact) to consider that interrupt/softirq are caused by Rx
746processing in kernel drivers, that user-land is caused by layer 7 processing
747in HAProxy, and that system time is caused by network processing on the Tx
748path.
749
750Since HAProxy runs around an event loop, it waits for new events using poll()
751(or any alternative) and processes all these events as fast as possible before
752going back to poll() waiting for new events. It measures the time spent waiting
753in poll() compared to the time spent doing processing events. The ratio of
754polling time vs total time is called the "idle" time, it's the amount of time
755spent waiting for something to happen. This ratio is reported in the stats page
756on the "idle" line, or "Idle_pct" on the CLI. When it's close to 100%, it means
757the load is extremely low. When it's close to 0%, it means that there is
758constantly some activity. While it cannot be very accurate on an overloaded
759system due to other processes possibly preempting the CPU from the haproxy
760process, it still provides a good estimate about how HAProxy considers it is
761working : if the load is low and the idle ratio is low as well, it may indicate
762that HAProxy has a lot of work to do, possibly due to very expensive rules that
763have to be processed. Conversely, if HAProxy indicates the idle is close to
764100% while things are slow, it means that it cannot do anything to speed things
765up because it is already waiting for incoming data to process. In the example
766below, haproxy is completely idle :
767
768 $ echo "show info" | socat - /var/run/haproxy.sock | grep ^Idle
769 Idle_pct: 100
770
771When the idle ratio starts to become very low, it is important to tune the
772system and place processes and interrupts correctly to save the most possible
773CPU resources for all tasks. If a firewall is present, it may be worth trying
774to disable it or to tune it to ensure it is not responsible for a large part
775of the performance limitation. It's worth noting that unloading a stateful
776firewall generally reduces both the amount of interrupt/softirq and of system
777usage since such firewalls act both on the Rx and the Tx paths. On Linux,
778unloading the nf_conntrack and ip_conntrack modules will show whether there is
779anything to gain. If so, then the module runs with default settings and you'll
780have to figure how to tune it for better performance. In general this consists
781in considerably increasing the hash table size. On FreeBSD, "pfctl -d" will
782disable the "pf" firewall and its stateful engine at the same time.
783
784If it is observed that a lot of time is spent in interrupt/softirq, it is
785important to ensure that they don't run on the same CPU. Most systems tend to
786pin the tasks on the CPU where they receive the network traffic because for
787certain workloads it improves things. But with heavily network-bound workloads
788it is the opposite as the haproxy process will have to fight against its kernel
789counterpart. Pinning haproxy to one CPU core and the interrupts to another one,
790all sharing the same L3 cache tends to sensibly increase network performance
791because in practice the amount of work for haproxy and the network stack are
792quite close, so they can almost fill an entire CPU each. On Linux this is done
793using taskset (for haproxy) or using cpu-map (from the haproxy config), and the
794interrupts are assigned under /proc/irq. Many network interfaces support
795multiple queues and multiple interrupts. In general it helps to spread them
796across a small number of CPU cores provided they all share the same L3 cache.
797Please always stop irq_balance which always does the worst possible thing on
798such workloads.
799
800For CPU-bound workloads consisting in a lot of SSL traffic or a lot of
801compression, it may be worth using multiple processes dedicated to certain
802tasks, though there is no universal rule here and experimentation will have to
803be performed.
804
805In order to increase the CPU capacity, it is possible to make HAProxy run as
806several processes, using the "nbproc" directive in the global section. There
807are some limitations though :
808 - health checks are run per process, so the target servers will get as many
809 checks as there are running processes ;
810 - maxconn values and queues are per-process so the correct value must be set
811 to avoid overloading the servers ;
812 - outgoing connections should avoid using port ranges to avoid conflicts
813 - stick-tables are per process and are not shared between processes ;
814 - each peers section may only run on a single process at a time ;
815 - the CLI operations will only act on a single process at a time.
816
817With this in mind, it appears that the easiest setup often consists in having
818one first layer running on multiple processes and in charge for the heavy
819processing, passing the traffic to a second layer running in a single process.
820This mechanism is suited to SSL and compression which are the two CPU-heavy
821features. Instances can easily be chained over UNIX sockets (which are cheaper
fengpeiyuancc123c62016-01-15 16:40:53 +0800822than TCP sockets and which do not waste ports), and the proxy protocol which is
Willy Tarreau2212e6a2015-10-13 14:40:55 +0200823useful to pass client information to the next stage. When doing so, it is
824generally a good idea to bind all the single-process tasks to process number 1
825and extra tasks to next processes, as this will make it easier to generate
826similar configurations for different machines.
827
828On Linux versions 3.9 and above, running HAProxy in multi-process mode is much
829more efficient when each process uses a distinct listening socket on the same
830IP:port ; this will make the kernel evenly distribute the load across all
831processes instead of waking them all up. Please check the "process" option of
832the "bind" keyword lines in the configuration manual for more information.
833
834
8358. Logging
836----------
837
838For logging, HAProxy always relies on a syslog server since it does not perform
839any file-system access. The standard way of using it is to send logs over UDP
840to the log server (by default on port 514). Very commonly this is configured to
841127.0.0.1 where the local syslog daemon is running, but it's also used over the
842network to log to a central server. The central server provides additional
843benefits especially in active-active scenarios where it is desirable to keep
844the logs merged in arrival order. HAProxy may also make use of a UNIX socket to
845send its logs to the local syslog daemon, but it is not recommended at all,
846because if the syslog server is restarted while haproxy runs, the socket will
847be replaced and new logs will be lost. Since HAProxy will be isolated inside a
848chroot jail, it will not have the ability to reconnect to the new socket. It
849has also been observed in field that the log buffers in use on UNIX sockets are
850very small and lead to lost messages even at very light loads. But this can be
851fine for testing however.
852
853It is recommended to add the following directive to the "global" section to
854make HAProxy log to the local daemon using facility "local0" :
855
856 log 127.0.0.1:514 local0
857
858and then to add the following one to each "defaults" section or to each frontend
859and backend section :
860
861 log global
862
863This way, all logs will be centralized through the global definition of where
864the log server is.
865
866Some syslog daemons do not listen to UDP traffic by default, so depending on
867the daemon being used, the syntax to enable this will vary :
868
869 - on sysklogd, you need to pass argument "-r" on the daemon's command line
870 so that it listens to a UDP socket for "remote" logs ; note that there is
871 no way to limit it to address 127.0.0.1 so it will also receive logs from
872 remote systems ;
873
874 - on rsyslogd, the following lines must be added to the configuration file :
875
876 $ModLoad imudp
877 $UDPServerAddress *
878 $UDPServerRun 514
879
880 - on syslog-ng, a new source can be created the following way, it then needs
881 to be added as a valid source in one of the "log" directives :
882
883 source s_udp {
884 udp(ip(127.0.0.1) port(514));
885 };
886
887Please consult your syslog daemon's manual for more information. If no logs are
888seen in the system's log files, please consider the following tests :
889
890 - restart haproxy. Each frontend and backend logs one line indicating it's
891 starting. If these logs are received, it means logs are working.
892
893 - run "strace -tt -s100 -etrace=sendmsg -p <haproxy's pid>" and perform some
894 activity that you expect to be logged. You should see the log messages
895 being sent using sendmsg() there. If they don't appear, restart using
896 strace on top of haproxy. If you still see no logs, it definitely means
897 that something is wrong in your configuration.
898
899 - run tcpdump to watch for port 514, for example on the loopback interface if
900 the traffic is being sent locally : "tcpdump -As0 -ni lo port 514". If the
901 packets are seen there, it's the proof they're sent then the syslogd daemon
902 needs to be troubleshooted.
903
904While traffic logs are sent from the frontends (where the incoming connections
905are accepted), backends also need to be able to send logs in order to report a
906server state change consecutive to a health check. Please consult HAProxy's
907configuration manual for more information regarding all possible log settings.
908
Dan Lloyd8e48b872016-07-01 21:01:18 -0400909It is convenient to chose a facility that is not used by other daemons. HAProxy
Willy Tarreau2212e6a2015-10-13 14:40:55 +0200910examples often suggest "local0" for traffic logs and "local1" for admin logs
911because they're never seen in field. A single facility would be enough as well.
912Having separate logs is convenient for log analysis, but it's also important to
913remember that logs may sometimes convey confidential information, and as such
Dan Lloyd8e48b872016-07-01 21:01:18 -0400914they must not be mixed with other logs that may accidentally be handed out to
Willy Tarreau2212e6a2015-10-13 14:40:55 +0200915unauthorized people.
916
917For in-field troubleshooting without impacting the server's capacity too much,
918it is recommended to make use of the "halog" utility provided with HAProxy.
919This is sort of a grep-like utility designed to process HAProxy log files at
920a very fast data rate. Typical figures range between 1 and 2 GB of logs per
921second. It is capable of extracting only certain logs (eg: search for some
922classes of HTTP status codes, connection termination status, search by response
923time ranges, look for errors only), count lines, limit the output to a number
924of lines, and perform some more advanced statistics such as sorting servers
925by response time or error counts, sorting URLs by time or count, sorting client
926addresses by access count, and so on. It is pretty convenient to quickly spot
927anomalies such as a bot looping on the site, and block them.
928
929
9309. Statistics and monitoring
931----------------------------
932
Willy Tarreau44aed902015-10-13 14:45:29 +0200933It is possible to query HAProxy about its status. The most commonly used
934mechanism is the HTTP statistics page. This page also exposes an alternative
935CSV output format for monitoring tools. The same format is provided on the
936Unix socket.
937
938
9399.1. CSV format
940---------------
941
942The statistics may be consulted either from the unix socket or from the HTTP
943page. Both means provide a CSV format whose fields follow. The first line
944begins with a sharp ('#') and has one word per comma-delimited field which
945represents the title of the column. All other lines starting at the second one
946use a classical CSV format using a comma as the delimiter, and the double quote
947('"') as an optional text delimiter, but only if the enclosed text is ambiguous
948(if it contains a quote or a comma). The double-quote character ('"') in the
949text is doubled ('""'), which is the format that most tools recognize. Please
950do not insert any column before these ones in order not to break tools which
951use hard-coded column positions.
952
953In brackets after each field name are the types which may have a value for
954that field. The types are L (Listeners), F (Frontends), B (Backends), and
955S (Servers).
956
957 0. pxname [LFBS]: proxy name
958 1. svname [LFBS]: service name (FRONTEND for frontend, BACKEND for backend,
959 any name for server/listener)
960 2. qcur [..BS]: current queued requests. For the backend this reports the
961 number queued without a server assigned.
962 3. qmax [..BS]: max value of qcur
963 4. scur [LFBS]: current sessions
964 5. smax [LFBS]: max sessions
965 6. slim [LFBS]: configured session limit
Willy Tarreauc73810f2016-01-11 13:52:04 +0100966 7. stot [LFBS]: cumulative number of sessions
Willy Tarreau44aed902015-10-13 14:45:29 +0200967 8. bin [LFBS]: bytes in
968 9. bout [LFBS]: bytes out
969 10. dreq [LFB.]: requests denied because of security concerns.
970 - For tcp this is because of a matched tcp-request content rule.
971 - For http this is because of a matched http-request or tarpit rule.
972 11. dresp [LFBS]: responses denied because of security concerns.
973 - For http this is because of a matched http-request rule, or
974 "option checkcache".
975 12. ereq [LF..]: request errors. Some of the possible causes are:
976 - early termination from the client, before the request has been sent.
977 - read error from the client
978 - client timeout
979 - client closed connection
980 - various bad requests from the client.
981 - request was tarpitted.
982 13. econ [..BS]: number of requests that encountered an error trying to
983 connect to a backend server. The backend stat is the sum of the stat
984 for all servers of that backend, plus any connection errors not
985 associated with a particular server (such as the backend having no
986 active servers).
987 14. eresp [..BS]: response errors. srv_abrt will be counted here also.
988 Some other errors are:
989 - write error on the client socket (won't be counted for the server stat)
990 - failure applying filters to the response.
991 15. wretr [..BS]: number of times a connection to a server was retried.
992 16. wredis [..BS]: number of times a request was redispatched to another
993 server. The server value counts the number of times that server was
994 switched away from.
Willy Tarreaub96dd282016-11-09 14:45:51 +0100995 17. status [LFBS]: status (UP/DOWN/NOLB/MAINT/MAINT(via)/MAINT(resolution)...)
Willy Tarreau44aed902015-10-13 14:45:29 +0200996 18. weight [..BS]: total weight (backend), server weight (server)
997 19. act [..BS]: number of active servers (backend), server is active (server)
998 20. bck [..BS]: number of backup servers (backend), server is backup (server)
999 21. chkfail [...S]: number of failed checks. (Only counts checks failed when
1000 the server is up.)
1001 22. chkdown [..BS]: number of UP->DOWN transitions. The backend counter counts
1002 transitions to the whole backend being down, rather than the sum of the
1003 counters for each server.
1004 23. lastchg [..BS]: number of seconds since the last UP<->DOWN transition
1005 24. downtime [..BS]: total downtime (in seconds). The value for the backend
1006 is the downtime for the whole backend, not the sum of the server downtime.
1007 25. qlimit [...S]: configured maxqueue for the server, or nothing in the
1008 value is 0 (default, meaning no limit)
1009 26. pid [LFBS]: process id (0 for first instance, 1 for second, ...)
1010 27. iid [LFBS]: unique proxy id
1011 28. sid [L..S]: server id (unique inside a proxy)
1012 29. throttle [...S]: current throttle percentage for the server, when
1013 slowstart is active, or no value if not in slowstart.
1014 30. lbtot [..BS]: total number of times a server was selected, either for new
1015 sessions, or when re-dispatching. The server counter is the number
1016 of times that server was selected.
1017 31. tracked [...S]: id of proxy/server if tracking is enabled.
1018 32. type [LFBS]: (0=frontend, 1=backend, 2=server, 3=socket/listener)
1019 33. rate [.FBS]: number of sessions per second over last elapsed second
1020 34. rate_lim [.F..]: configured limit on new sessions per second
1021 35. rate_max [.FBS]: max number of new sessions per second
1022 36. check_status [...S]: status of last health check, one of:
1023 UNK -> unknown
1024 INI -> initializing
1025 SOCKERR -> socket error
1026 L4OK -> check passed on layer 4, no upper layers testing enabled
1027 L4TOUT -> layer 1-4 timeout
1028 L4CON -> layer 1-4 connection problem, for example
1029 "Connection refused" (tcp rst) or "No route to host" (icmp)
1030 L6OK -> check passed on layer 6
1031 L6TOUT -> layer 6 (SSL) timeout
1032 L6RSP -> layer 6 invalid response - protocol error
1033 L7OK -> check passed on layer 7
1034 L7OKC -> check conditionally passed on layer 7, for example 404 with
1035 disable-on-404
1036 L7TOUT -> layer 7 (HTTP/SMTP) timeout
1037 L7RSP -> layer 7 invalid response - protocol error
1038 L7STS -> layer 7 response error, for example HTTP 5xx
Daniel Schnellerb6c8b0d2017-09-01 19:13:55 +02001039 Notice: If a check is currently running, the last known status will be
1040 reported, prefixed with "* ". e. g. "* L7OK".
Willy Tarreau44aed902015-10-13 14:45:29 +02001041 37. check_code [...S]: layer5-7 code, if available
1042 38. check_duration [...S]: time in ms took to finish last health check
1043 39. hrsp_1xx [.FBS]: http responses with 1xx code
1044 40. hrsp_2xx [.FBS]: http responses with 2xx code
1045 41. hrsp_3xx [.FBS]: http responses with 3xx code
1046 42. hrsp_4xx [.FBS]: http responses with 4xx code
1047 43. hrsp_5xx [.FBS]: http responses with 5xx code
1048 44. hrsp_other [.FBS]: http responses with other codes (protocol error)
1049 45. hanafail [...S]: failed health checks details
1050 46. req_rate [.F..]: HTTP requests per second over last elapsed second
1051 47. req_rate_max [.F..]: max number of HTTP requests per second observed
Willy Tarreaufb981bd2016-12-12 14:31:46 +01001052 48. req_tot [.FB.]: total number of HTTP requests received
Willy Tarreau44aed902015-10-13 14:45:29 +02001053 49. cli_abrt [..BS]: number of data transfers aborted by the client
1054 50. srv_abrt [..BS]: number of data transfers aborted by the server
1055 (inc. in eresp)
1056 51. comp_in [.FB.]: number of HTTP response bytes fed to the compressor
1057 52. comp_out [.FB.]: number of HTTP response bytes emitted by the compressor
1058 53. comp_byp [.FB.]: number of bytes that bypassed the HTTP compressor
1059 (CPU/BW limit)
1060 54. comp_rsp [.FB.]: number of HTTP responses that were compressed
1061 55. lastsess [..BS]: number of seconds since last session assigned to
1062 server/backend
1063 56. last_chk [...S]: last health check contents or textual error
1064 57. last_agt [...S]: last agent check contents or textual error
1065 58. qtime [..BS]: the average queue time in ms over the 1024 last requests
1066 59. ctime [..BS]: the average connect time in ms over the 1024 last requests
1067 60. rtime [..BS]: the average response time in ms over the 1024 last requests
1068 (0 for TCP)
1069 61. ttime [..BS]: the average total session time in ms over the 1024 last
1070 requests
Willy Tarreau7f618842016-01-08 11:40:03 +01001071 62. agent_status [...S]: status of last agent check, one of:
1072 UNK -> unknown
1073 INI -> initializing
1074 SOCKERR -> socket error
1075 L4OK -> check passed on layer 4, no upper layers testing enabled
1076 L4TOUT -> layer 1-4 timeout
1077 L4CON -> layer 1-4 connection problem, for example
1078 "Connection refused" (tcp rst) or "No route to host" (icmp)
1079 L7OK -> agent reported "up"
1080 L7STS -> agent reported "fail", "stop", or "down"
1081 63. agent_code [...S]: numeric code reported by agent if any (unused for now)
1082 64. agent_duration [...S]: time in ms taken to finish last check
Willy Tarreaudd7354b2016-01-08 13:47:26 +01001083 65. check_desc [...S]: short human-readable description of check_status
1084 66. agent_desc [...S]: short human-readable description of agent_status
Willy Tarreau3141f592016-01-08 14:25:28 +01001085 67. check_rise [...S]: server's "rise" parameter used by checks
1086 68. check_fall [...S]: server's "fall" parameter used by checks
1087 69. check_health [...S]: server's health check value between 0 and rise+fall-1
1088 70. agent_rise [...S]: agent's "rise" parameter, normally 1
1089 71. agent_fall [...S]: agent's "fall" parameter, normally 1
1090 72. agent_health [...S]: agent's health parameter, between 0 and rise+fall-1
Willy Tarreaua6f5a732016-01-08 16:59:56 +01001091 73. addr [L..S]: address:port or "unix". IPv6 has brackets around the address.
Willy Tarreaue4847c62016-01-08 15:43:54 +01001092 74: cookie [..BS]: server's cookie value or backend's cookie name
Willy Tarreauf8211df2016-01-11 14:09:38 +01001093 75: mode [LFBS]: proxy mode (tcp, http, health, unknown)
Willy Tarreauf1516d92016-01-11 14:48:36 +01001094 76: algo [..B.]: load balancing algorithm
Willy Tarreauc73810f2016-01-11 13:52:04 +01001095 77: conn_rate [.F..]: number of connections over the last elapsed second
1096 78: conn_rate_max [.F..]: highest known conn_rate
1097 79: conn_tot [.F..]: cumulative number of connections
Willy Tarreau5b9bdff2016-01-11 14:40:47 +01001098 80: intercepted [.FB.]: cum. number of intercepted requests (monitor, stats)
Willy Tarreau8a90b8e2016-10-21 18:15:32 +02001099 81: dcon [LF..]: requests denied by "tcp-request connection" rules
Willy Tarreaua5bc36b2016-10-21 18:16:27 +02001100 82: dses [LF..]: requests denied by "tcp-request session" rules
Willy Tarreauea96a822018-05-28 15:15:43 +02001101 83: wrew [LFBS]: cumulative number of failed header rewriting warnings
Jérôme Magnin708eb882019-07-17 09:24:46 +02001102 84: connect [..BS]: cumulative number of connection establishment attempts
1103 85: reuse [..BS]: cumulative number of connection reuses
Willy Tarreau72974292019-11-08 07:29:34 +01001104 86: cache_lookups [.FB.]: cumulative number of cache lookups
Jérôme Magnin34ebb5c2019-07-17 14:04:40 +02001105 87: cache_hits [.FB.]: cumulative number of cache hits
Christopher Faulet2ac25742019-11-08 15:27:27 +01001106 88: srv_icur [...S]: current number of idle connections available for reuse
1107 89: src_ilim [...S]: limit on the number of available idle connections
1108 90. qtime_max [..BS]: the maximum observed queue time in ms
1109 91. ctime_max [..BS]: the maximum observed connect time in ms
1110 92. rtime_max [..BS]: the maximum observed response time in ms (0 for TCP)
1111 93. ttime_max [..BS]: the maximum observed total session time in ms
Willy Tarreau44aed902015-10-13 14:45:29 +02001112
1113
Willy Tarreau5d8b9792016-03-11 11:09:34 +010011149.2) Typed output format
1115------------------------
1116
1117Both "show info" and "show stat" support a mode where each output value comes
1118with its type and sufficient information to know how the value is supposed to
1119be aggregated between processes and how it evolves.
1120
1121In all cases, the output consists in having a single value per line with all
1122the information split into fields delimited by colons (':').
1123
1124The first column designates the object or metric being dumped. Its format is
1125specific to the command producing this output and will not be described in this
1126section. Usually it will consist in a series of identifiers and field names.
1127
1128The second column contains 3 characters respectively indicating the origin, the
1129nature and the scope of the value being reported. The first character (the
1130origin) indicates where the value was extracted from. Possible characters are :
1131
1132 M The value is a metric. It is valid at one instant any may change depending
1133 on its nature .
1134
1135 S The value is a status. It represents a discrete value which by definition
1136 cannot be aggregated. It may be the status of a server ("UP" or "DOWN"),
1137 the PID of the process, etc.
1138
1139 K The value is a sorting key. It represents an identifier which may be used
1140 to group some values together because it is unique among its class. All
1141 internal identifiers are keys. Some names can be listed as keys if they
1142 are unique (eg: a frontend name is unique). In general keys come from the
Dan Lloyd8e48b872016-07-01 21:01:18 -04001143 configuration, even though some of them may automatically be assigned. For
Willy Tarreau5d8b9792016-03-11 11:09:34 +01001144 most purposes keys may be considered as equivalent to configuration.
1145
1146 C The value comes from the configuration. Certain configuration values make
1147 sense on the output, for example a concurrent connection limit or a cookie
1148 name. By definition these values are the same in all processes started
1149 from the same configuration file.
1150
1151 P The value comes from the product itself. There are very few such values,
1152 most common use is to report the product name, version and release date.
1153 These elements are also the same between all processes.
1154
1155The second character (the nature) indicates the nature of the information
1156carried by the field in order to let an aggregator decide on what operation to
1157use to aggregate multiple values. Possible characters are :
1158
1159 A The value represents an age since a last event. This is a bit different
1160 from the duration in that an age is automatically computed based on the
1161 current date. A typical example is how long ago did the last session
1162 happen on a server. Ages are generally aggregated by taking the minimum
1163 value and do not need to be stored.
1164
1165 a The value represents an already averaged value. The average response times
1166 and server weights are of this nature. Averages can typically be averaged
1167 between processes.
1168
1169 C The value represents a cumulative counter. Such measures perpetually
1170 increase until they wrap around. Some monitoring protocols need to tell
1171 the difference between a counter and a gauge to report a different type.
1172 In general counters may simply be summed since they represent events or
1173 volumes. Examples of metrics of this nature are connection counts or byte
1174 counts.
1175
1176 D The value represents a duration for a status. There are a few usages of
1177 this, most of them include the time taken by the last health check and
1178 the time a server has spent down. Durations are generally not summed,
1179 most of the time the maximum will be retained to compute an SLA.
1180
1181 G The value represents a gauge. It's a measure at one instant. The memory
1182 usage or the current number of active connections are of this nature.
1183 Metrics of this type are typically summed during aggregation.
1184
1185 L The value represents a limit (generally a configured one). By nature,
1186 limits are harder to aggregate since they are specific to the point where
1187 they were retrieved. In certain situations they may be summed or be kept
1188 separate.
1189
1190 M The value represents a maximum. In general it will apply to a gauge and
1191 keep the highest known value. An example of such a metric could be the
1192 maximum amount of concurrent connections that was encountered in the
1193 product's life time. To correctly aggregate maxima, you are supposed to
1194 output a range going from the maximum of all maxima and the sum of all
1195 of them. There is indeed no way to know if they were encountered
1196 simultaneously or not.
1197
1198 m The value represents a minimum. In general it will apply to a gauge and
1199 keep the lowest known value. An example of such a metric could be the
1200 minimum amount of free memory pools that was encountered in the product's
1201 life time. To correctly aggregate minima, you are supposed to output a
1202 range going from the minimum of all minima and the sum of all of them.
1203 There is indeed no way to know if they were encountered simultaneously
1204 or not.
1205
1206 N The value represents a name, so it is a string. It is used to report
1207 proxy names, server names and cookie names. Names have configuration or
1208 keys as their origin and are supposed to be the same among all processes.
1209
1210 O The value represents a free text output. Outputs from various commands,
1211 returns from health checks, node descriptions are of such nature.
1212
1213 R The value represents an event rate. It's a measure at one instant. It is
1214 quite similar to a gauge except that the recipient knows that this measure
1215 moves slowly and may decide not to keep all values. An example of such a
1216 metric is the measured amount of connections per second. Metrics of this
1217 type are typically summed during aggregation.
1218
1219 T The value represents a date or time. A field emitting the current date
1220 would be of this type. The method to aggregate such information is left
1221 as an implementation choice. For now no field uses this type.
1222
1223The third character (the scope) indicates what extent the value reflects. Some
1224elements may be per process while others may be per configuration or per system.
1225The distinction is important to know whether or not a single value should be
1226kept during aggregation or if values have to be aggregated. The following
1227characters are currently supported :
1228
1229 C The value is valid for a whole cluster of nodes, which is the set of nodes
1230 communicating over the peers protocol. An example could be the amount of
1231 entries present in a stick table that is replicated with other peers. At
1232 the moment no metric use this scope.
1233
1234 P The value is valid only for the process reporting it. Most metrics use
1235 this scope.
1236
1237 S The value is valid for the whole service, which is the set of processes
1238 started together from the same configuration file. All metrics originating
1239 from the configuration use this scope. Some other metrics may use it as
1240 well for some shared resources (eg: shared SSL cache statistics).
1241
1242 s The value is valid for the whole system, such as the system's hostname,
1243 current date or resource usage. At the moment this scope is not used by
1244 any metric.
1245
1246Consumers of these information will generally have enough of these 3 characters
1247to determine how to accurately report aggregated information across multiple
1248processes.
1249
1250After this column, the third column indicates the type of the field, among "s32"
1251(signed 32-bit integer), "s64" (signed 64-bit integer), "u32" (unsigned 32-bit
1252integer), "u64" (unsigned 64-bit integer), "str" (string). It is important to
1253know the type before parsing the value in order to properly read it. For example
1254a string containing only digits is still a string an not an integer (eg: an
1255error code extracted by a check).
1256
1257Then the fourth column is the value itself, encoded according to its type.
1258Strings are dumped as-is immediately after the colon without any leading space.
1259If a string contains a colon, it will appear normally. This means that the
1260output should not be exclusively split around colons or some check outputs
1261or server addresses might be truncated.
1262
1263
12649.3. Unix Socket commands
Willy Tarreau44aed902015-10-13 14:45:29 +02001265-------------------------
1266
1267The stats socket is not enabled by default. In order to enable it, it is
1268necessary to add one line in the global section of the haproxy configuration.
1269A second line is recommended to set a larger timeout, always appreciated when
1270issuing commands by hand :
1271
1272 global
1273 stats socket /var/run/haproxy.sock mode 600 level admin
1274 stats timeout 2m
1275
1276It is also possible to add multiple instances of the stats socket by repeating
1277the line, and make them listen to a TCP port instead of a UNIX socket. This is
1278never done by default because this is dangerous, but can be handy in some
1279situations :
1280
1281 global
1282 stats socket /var/run/haproxy.sock mode 600 level admin
1283 stats socket ipv4@192.168.0.1:9999 level admin
1284 stats timeout 2m
1285
1286To access the socket, an external utility such as "socat" is required. Socat is
1287a swiss-army knife to connect anything to anything. We use it to connect
1288terminals to the socket, or a couple of stdin/stdout pipes to it for scripts.
1289The two main syntaxes we'll use are the following :
1290
1291 # socat /var/run/haproxy.sock stdio
1292 # socat /var/run/haproxy.sock readline
1293
1294The first one is used with scripts. It is possible to send the output of a
1295script to haproxy, and pass haproxy's output to another script. That's useful
1296for retrieving counters or attack traces for example.
1297
1298The second one is only useful for issuing commands by hand. It has the benefit
1299that the terminal is handled by the readline library which supports line
1300editing and history, which is very convenient when issuing repeated commands
1301(eg: watch a counter).
1302
1303The socket supports two operation modes :
1304 - interactive
1305 - non-interactive
1306
1307The non-interactive mode is the default when socat connects to the socket. In
1308this mode, a single line may be sent. It is processed as a whole, responses are
1309sent back, and the connection closes after the end of the response. This is the
1310mode that scripts and monitoring tools use. It is possible to send multiple
1311commands in this mode, they need to be delimited by a semi-colon (';'). For
1312example :
1313
1314 # echo "show info;show stat;show table" | socat /var/run/haproxy stdio
1315
Dragan Dosena1c35ab2016-11-24 11:33:12 +01001316If a command needs to use a semi-colon or a backslash (eg: in a value), it
Joseph Herlant71b4b152018-11-13 16:55:16 -08001317must be preceded by a backslash ('\').
Chad Lavoiee3f50312016-05-26 16:42:25 -04001318
Willy Tarreau44aed902015-10-13 14:45:29 +02001319The interactive mode displays a prompt ('>') and waits for commands to be
1320entered on the line, then processes them, and displays the prompt again to wait
1321for a new command. This mode is entered via the "prompt" command which must be
1322sent on the first line in non-interactive mode. The mode is a flip switch, if
1323"prompt" is sent in interactive mode, it is disabled and the connection closes
1324after processing the last command of the same line.
1325
1326For this reason, when debugging by hand, it's quite common to start with the
1327"prompt" command :
1328
1329 # socat /var/run/haproxy readline
1330 prompt
1331 > show info
1332 ...
1333 >
1334
1335Since multiple commands may be issued at once, haproxy uses the empty line as a
1336delimiter to mark an end of output for each command, and takes care of ensuring
1337that no command can emit an empty line on output. A script can thus easily
1338parse the output even when multiple commands were pipelined on a single line.
1339
Aurélien Nephtaliabbf6072018-04-18 13:26:46 +02001340Some commands may take an optional payload. To add one to a command, the first
1341line needs to end with the "<<\n" pattern. The next lines will be treated as
1342the payload and can contain as many lines as needed. To validate a command with
1343a payload, it needs to end with an empty line.
1344
1345Limitations do exist: the length of the whole buffer passed to the CLI must
1346not be greater than tune.bfsize and the pattern "<<" must not be glued to the
1347last word of the line.
1348
1349When entering a paylod while in interactive mode, the prompt will change from
1350"> " to "+ ".
1351
Willy Tarreau44aed902015-10-13 14:45:29 +02001352It is important to understand that when multiple haproxy processes are started
1353on the same sockets, any process may pick up the request and will output its
1354own stats.
1355
1356The list of commands currently supported on the stats socket is provided below.
1357If an unknown command is sent, haproxy displays the usage message which reminds
1358all supported commands. Some commands support a more complex syntax, generally
1359it will explain what part of the command is invalid when this happens.
1360
Olivier Doucetd8703e82017-08-31 11:05:10 +02001361Some commands require a higher level of privilege to work. If you do not have
1362enough privilege, you will get an error "Permission denied". Please check
1363the "level" option of the "bind" keyword lines in the configuration manual
1364for more information.
1365
Willy Tarreau44aed902015-10-13 14:45:29 +02001366add acl <acl> <pattern>
1367 Add an entry into the acl <acl>. <acl> is the #<id> or the <file> returned by
1368 "show acl". This command does not verify if the entry already exists. This
1369 command cannot be used if the reference <acl> is a file also used with a map.
1370 In this case, you must use the command "add map" in place of "add acl".
1371
1372add map <map> <key> <value>
Aurélien Nephtali25650ce2018-04-18 14:04:47 +02001373add map <map> <payload>
Willy Tarreau44aed902015-10-13 14:45:29 +02001374 Add an entry into the map <map> to associate the value <value> to the key
1375 <key>. This command does not verify if the entry already exists. It is
1376 mainly used to fill a map after a clear operation. Note that if the reference
1377 <map> is a file and is shared with a map, this map will contain also a new
Aurélien Nephtali25650ce2018-04-18 14:04:47 +02001378 pattern entry. Using the payload syntax it is possible to add multiple
1379 key/value pairs by entering them on separate lines. On each new line, the
1380 first word is the key and the rest of the line is considered to be the value
1381 which can even contains spaces.
1382
1383 Example:
1384
1385 # socat /tmp/sock1 -
1386 prompt
1387
1388 > add map #-1 <<
1389 + key1 value1
1390 + key2 value2 with spaces
1391 + key3 value3 also with spaces
1392 + key4 value4
1393
1394 >
Willy Tarreau44aed902015-10-13 14:45:29 +02001395
1396clear counters
1397 Clear the max values of the statistics counters in each proxy (frontend &
Willy Tarreaud80cb4e2018-01-20 19:30:13 +01001398 backend) and in each server. The accumulated counters are not affected. The
1399 internal activity counters reported by "show activity" are also reset. This
Willy Tarreau44aed902015-10-13 14:45:29 +02001400 can be used to get clean counters after an incident, without having to
1401 restart nor to clear traffic counters. This command is restricted and can
1402 only be issued on sockets configured for levels "operator" or "admin".
1403
1404clear counters all
1405 Clear all statistics counters in each proxy (frontend & backend) and in each
1406 server. This has the same effect as restarting. This command is restricted
1407 and can only be issued on sockets configured for level "admin".
1408
1409clear acl <acl>
1410 Remove all entries from the acl <acl>. <acl> is the #<id> or the <file>
1411 returned by "show acl". Note that if the reference <acl> is a file and is
1412 shared with a map, this map will be also cleared.
1413
1414clear map <map>
1415 Remove all entries from the map <map>. <map> is the #<id> or the <file>
1416 returned by "show map". Note that if the reference <map> is a file and is
1417 shared with a acl, this acl will be also cleared.
1418
1419clear table <table> [ data.<type> <operator> <value> ] | [ key <key> ]
1420 Remove entries from the stick-table <table>.
1421
1422 This is typically used to unblock some users complaining they have been
1423 abusively denied access to a service, but this can also be used to clear some
1424 stickiness entries matching a server that is going to be replaced (see "show
1425 table" below for details). Note that sometimes, removal of an entry will be
1426 refused because it is currently tracked by a session. Retrying a few seconds
1427 later after the session ends is usual enough.
1428
1429 In the case where no options arguments are given all entries will be removed.
1430
1431 When the "data." form is used entries matching a filter applied using the
1432 stored data (see "stick-table" in section 4.2) are removed. A stored data
1433 type must be specified in <type>, and this data type must be stored in the
1434 table otherwise an error is reported. The data is compared according to
1435 <operator> with the 64-bit integer <value>. Operators are the same as with
1436 the ACLs :
1437
1438 - eq : match entries whose data is equal to this value
1439 - ne : match entries whose data is not equal to this value
1440 - le : match entries whose data is less than or equal to this value
1441 - ge : match entries whose data is greater than or equal to this value
1442 - lt : match entries whose data is less than this value
1443 - gt : match entries whose data is greater than this value
1444
1445 When the key form is used the entry <key> is removed. The key must be of the
1446 same type as the table, which currently is limited to IPv4, IPv6, integer and
1447 string.
1448
1449 Example :
1450 $ echo "show table http_proxy" | socat stdio /tmp/sock1
1451 >>> # table: http_proxy, type: ip, size:204800, used:2
1452 >>> 0x80e6a4c: key=127.0.0.1 use=0 exp=3594729 gpc0=0 conn_rate(30000)=1 \
1453 bytes_out_rate(60000)=187
1454 >>> 0x80e6a80: key=127.0.0.2 use=0 exp=3594740 gpc0=1 conn_rate(30000)=10 \
1455 bytes_out_rate(60000)=191
1456
1457 $ echo "clear table http_proxy key 127.0.0.1" | socat stdio /tmp/sock1
1458
1459 $ echo "show table http_proxy" | socat stdio /tmp/sock1
1460 >>> # table: http_proxy, type: ip, size:204800, used:1
1461 >>> 0x80e6a80: key=127.0.0.2 use=0 exp=3594740 gpc0=1 conn_rate(30000)=10 \
1462 bytes_out_rate(60000)=191
1463 $ echo "clear table http_proxy data.gpc0 eq 1" | socat stdio /tmp/sock1
1464 $ echo "show table http_proxy" | socat stdio /tmp/sock1
1465 >>> # table: http_proxy, type: ip, size:204800, used:1
1466
Willy Tarreau6bdf3e92019-05-20 14:25:05 +02001467debug dev <command> [args]*
Willy Tarreaub24ab222019-10-24 18:03:39 +02001468 Call a developer-specific command. Only supported on a CLI connection running
1469 in expert mode (see "expert-mode on"). Such commands are extremely dangerous
1470 and not forgiving, any misuse may result in a crash of the process. They are
1471 intended for experts only, and must really not be used unless told to do so.
1472 Some of them are only available when haproxy is built with DEBUG_DEV defined
1473 because they may have security implications. All of these commands require
1474 admin privileges, and are purposely not documented to avoid encouraging their
1475 use by people who are not at ease with the source code.
Willy Tarreau6bdf3e92019-05-20 14:25:05 +02001476
Willy Tarreau44aed902015-10-13 14:45:29 +02001477del acl <acl> [<key>|#<ref>]
1478 Delete all the acl entries from the acl <acl> corresponding to the key <key>.
1479 <acl> is the #<id> or the <file> returned by "show acl". If the <ref> is used,
1480 this command delete only the listed reference. The reference can be found with
1481 listing the content of the acl. Note that if the reference <acl> is a file and
1482 is shared with a map, the entry will be also deleted in the map.
1483
1484del map <map> [<key>|#<ref>]
1485 Delete all the map entries from the map <map> corresponding to the key <key>.
1486 <map> is the #<id> or the <file> returned by "show map". If the <ref> is used,
1487 this command delete only the listed reference. The reference can be found with
1488 listing the content of the map. Note that if the reference <map> is a file and
1489 is shared with a acl, the entry will be also deleted in the map.
1490
1491disable agent <backend>/<server>
1492 Mark the auxiliary agent check as temporarily stopped.
1493
1494 In the case where an agent check is being run as a auxiliary check, due
1495 to the agent-check parameter of a server directive, new checks are only
Dan Lloyd8e48b872016-07-01 21:01:18 -04001496 initialized when the agent is in the enabled. Thus, disable agent will
Willy Tarreau44aed902015-10-13 14:45:29 +02001497 prevent any new agent checks from begin initiated until the agent
1498 re-enabled using enable agent.
1499
1500 When an agent is disabled the processing of an auxiliary agent check that
1501 was initiated while the agent was set as enabled is as follows: All
1502 results that would alter the weight, specifically "drain" or a weight
1503 returned by the agent, are ignored. The processing of agent check is
1504 otherwise unchanged.
1505
1506 The motivation for this feature is to allow the weight changing effects
1507 of the agent checks to be paused to allow the weight of a server to be
1508 configured using set weight without being overridden by the agent.
1509
1510 This command is restricted and can only be issued on sockets configured for
1511 level "admin".
1512
Olivier Houchard614f8d72017-03-14 20:08:46 +01001513disable dynamic-cookie backend <backend>
1514 Disable the generation of dynamic cookies fot the backend <backend>
1515
Willy Tarreau44aed902015-10-13 14:45:29 +02001516disable frontend <frontend>
1517 Mark the frontend as temporarily stopped. This corresponds to the mode which
1518 is used during a soft restart : the frontend releases the port but can be
1519 enabled again if needed. This should be used with care as some non-Linux OSes
1520 are unable to enable it back. This is intended to be used in environments
1521 where stopping a proxy is not even imaginable but a misconfigured proxy must
1522 be fixed. That way it's possible to release the port and bind it into another
1523 process to restore operations. The frontend will appear with status "STOP"
1524 on the stats page.
1525
1526 The frontend may be specified either by its name or by its numeric ID,
1527 prefixed with a sharp ('#').
1528
1529 This command is restricted and can only be issued on sockets configured for
1530 level "admin".
1531
1532disable health <backend>/<server>
1533 Mark the primary health check as temporarily stopped. This will disable
1534 sending of health checks, and the last health check result will be ignored.
1535 The server will be in unchecked state and considered UP unless an auxiliary
1536 agent check forces it down.
1537
1538 This command is restricted and can only be issued on sockets configured for
1539 level "admin".
1540
1541disable server <backend>/<server>
1542 Mark the server DOWN for maintenance. In this mode, no more checks will be
1543 performed on the server until it leaves maintenance.
1544 If the server is tracked by other servers, those servers will be set to DOWN
1545 during the maintenance.
1546
1547 In the statistics page, a server DOWN for maintenance will appear with a
1548 "MAINT" status, its tracking servers with the "MAINT(via)" one.
1549
1550 Both the backend and the server may be specified either by their name or by
1551 their numeric ID, prefixed with a sharp ('#').
1552
1553 This command is restricted and can only be issued on sockets configured for
1554 level "admin".
1555
1556enable agent <backend>/<server>
1557 Resume auxiliary agent check that was temporarily stopped.
1558
1559 See "disable agent" for details of the effect of temporarily starting
1560 and stopping an auxiliary agent.
1561
1562 This command is restricted and can only be issued on sockets configured for
1563 level "admin".
1564
Olivier Houchard614f8d72017-03-14 20:08:46 +01001565enable dynamic-cookie backend <backend>
n9@users.noreply.github.com25a1c8e2019-08-23 11:21:05 +02001566 Enable the generation of dynamic cookies for the backend <backend>.
1567 A secret key must also be provided.
Olivier Houchard614f8d72017-03-14 20:08:46 +01001568
Willy Tarreau44aed902015-10-13 14:45:29 +02001569enable frontend <frontend>
1570 Resume a frontend which was temporarily stopped. It is possible that some of
1571 the listening ports won't be able to bind anymore (eg: if another process
1572 took them since the 'disable frontend' operation). If this happens, an error
1573 is displayed. Some operating systems might not be able to resume a frontend
1574 which was disabled.
1575
1576 The frontend may be specified either by its name or by its numeric ID,
1577 prefixed with a sharp ('#').
1578
1579 This command is restricted and can only be issued on sockets configured for
1580 level "admin".
1581
1582enable health <backend>/<server>
1583 Resume a primary health check that was temporarily stopped. This will enable
1584 sending of health checks again. Please see "disable health" for details.
1585
1586 This command is restricted and can only be issued on sockets configured for
1587 level "admin".
1588
1589enable server <backend>/<server>
1590 If the server was previously marked as DOWN for maintenance, this marks the
1591 server UP and checks are re-enabled.
1592
1593 Both the backend and the server may be specified either by their name or by
1594 their numeric ID, prefixed with a sharp ('#').
1595
1596 This command is restricted and can only be issued on sockets configured for
1597 level "admin".
1598
Willy Tarreauabb9f9b2019-10-24 17:55:53 +02001599expert-mode [on|off]
1600 Without options, this indicates whether the expert mode is enabled or
1601 disabled on the current connection. When passed "on", it turns the expert
1602 mode on for the current CLI connection only. With "off" it turns it off. The
1603 expert mode enables displaying of expert commands that can be extremely
1604 dangerous for the process and which may occasionally help developers collect
1605 important information about complex bugs. Any misuse of these features will
1606 likely lead to a process crash. Do not use this option without being invited
1607 to do so. Note that this command is purposely not listed in the help message.
1608 This command is only accessible in admin level. Changing to another level
1609 automatically resets the expert mode.
1610
Willy Tarreau44aed902015-10-13 14:45:29 +02001611get map <map> <value>
1612get acl <acl> <value>
1613 Lookup the value <value> in the map <map> or in the ACL <acl>. <map> or <acl>
1614 are the #<id> or the <file> returned by "show map" or "show acl". This command
1615 returns all the matching patterns associated with this map. This is useful for
1616 debugging maps and ACLs. The output format is composed by one line par
1617 matching type. Each line is composed by space-delimited series of words.
1618
1619 The first two words are:
1620
1621 <match method>: The match method applied. It can be "found", "bool",
1622 "int", "ip", "bin", "len", "str", "beg", "sub", "dir",
1623 "dom", "end" or "reg".
1624
1625 <match result>: The result. Can be "match" or "no-match".
1626
1627 The following words are returned only if the pattern matches an entry.
1628
1629 <index type>: "tree" or "list". The internal lookup algorithm.
1630
1631 <case>: "case-insensitive" or "case-sensitive". The
1632 interpretation of the case.
1633
1634 <entry matched>: match="<entry>". Return the matched pattern. It is
1635 useful with regular expressions.
1636
1637 The two last word are used to show the returned value and its type. With the
1638 "acl" case, the pattern doesn't exist.
1639
1640 return=nothing: No return because there are no "map".
1641 return="<value>": The value returned in the string format.
1642 return=cannot-display: The value cannot be converted as string.
1643
1644 type="<type>": The type of the returned sample.
1645
1646get weight <backend>/<server>
1647 Report the current weight and the initial weight of server <server> in
1648 backend <backend> or an error if either doesn't exist. The initial weight is
1649 the one that appears in the configuration file. Both are normally equal
1650 unless the current weight has been changed. Both the backend and the server
1651 may be specified either by their name or by their numeric ID, prefixed with a
1652 sharp ('#').
1653
1654help
1655 Print the list of known keywords and their basic usage. The same help screen
1656 is also displayed for unknown commands.
1657
1658prompt
1659 Toggle the prompt at the beginning of the line and enter or leave interactive
1660 mode. In interactive mode, the connection is not closed after a command
1661 completes. Instead, the prompt will appear again, indicating the user that
1662 the interpreter is waiting for a new command. The prompt consists in a right
1663 angle bracket followed by a space "> ". This mode is particularly convenient
1664 when one wants to periodically check information such as stats or errors.
1665 It is also a good idea to enter interactive mode before issuing a "help"
1666 command.
1667
1668quit
1669 Close the connection when in interactive mode.
1670
Olivier Houchard614f8d72017-03-14 20:08:46 +01001671set dynamic-cookie-key backend <backend> <value>
1672 Modify the secret key used to generate the dynamic persistent cookies.
1673 This will break the existing sessions.
1674
Willy Tarreau44aed902015-10-13 14:45:29 +02001675set map <map> [<key>|#<ref>] <value>
1676 Modify the value corresponding to each key <key> in a map <map>. <map> is the
1677 #<id> or <file> returned by "show map". If the <ref> is used in place of
1678 <key>, only the entry pointed by <ref> is changed. The new value is <value>.
1679
1680set maxconn frontend <frontend> <value>
1681 Dynamically change the specified frontend's maxconn setting. Any positive
1682 value is allowed including zero, but setting values larger than the global
1683 maxconn does not make much sense. If the limit is increased and connections
1684 were pending, they will immediately be accepted. If it is lowered to a value
1685 below the current number of connections, new connections acceptation will be
1686 delayed until the threshold is reached. The frontend might be specified by
1687 either its name or its numeric ID prefixed with a sharp ('#').
1688
Andrew Hayworthedb93a72015-10-27 21:46:25 +00001689set maxconn server <backend/server> <value>
1690 Dynamically change the specified server's maxconn setting. Any positive
1691 value is allowed including zero, but setting values larger than the global
1692 maxconn does not make much sense.
1693
Willy Tarreau44aed902015-10-13 14:45:29 +02001694set maxconn global <maxconn>
1695 Dynamically change the global maxconn setting within the range defined by the
1696 initial global maxconn setting. If it is increased and connections were
1697 pending, they will immediately be accepted. If it is lowered to a value below
1698 the current number of connections, new connections acceptation will be
1699 delayed until the threshold is reached. A value of zero restores the initial
1700 setting.
1701
Willy Tarreaud2d33482019-04-25 17:09:07 +02001702set profiling { tasks } { auto | on | off }
Willy Tarreau75c62c22018-11-22 11:02:09 +01001703 Enables or disables CPU profiling for the indicated subsystem. This is
1704 equivalent to setting or clearing the "profiling" settings in the "global"
1705 section of the configuration file. Please also see "show profiling".
1706
Willy Tarreau44aed902015-10-13 14:45:29 +02001707set rate-limit connections global <value>
1708 Change the process-wide connection rate limit, which is set by the global
1709 'maxconnrate' setting. A value of zero disables the limitation. This limit
1710 applies to all frontends and the change has an immediate effect. The value
1711 is passed in number of connections per second.
1712
1713set rate-limit http-compression global <value>
1714 Change the maximum input compression rate, which is set by the global
1715 'maxcomprate' setting. A value of zero disables the limitation. The value is
1716 passed in number of kilobytes per second. The value is available in the "show
1717 info" on the line "CompressBpsRateLim" in bytes.
1718
1719set rate-limit sessions global <value>
1720 Change the process-wide session rate limit, which is set by the global
1721 'maxsessrate' setting. A value of zero disables the limitation. This limit
1722 applies to all frontends and the change has an immediate effect. The value
1723 is passed in number of sessions per second.
1724
1725set rate-limit ssl-sessions global <value>
1726 Change the process-wide SSL session rate limit, which is set by the global
1727 'maxsslrate' setting. A value of zero disables the limitation. This limit
1728 applies to all frontends and the change has an immediate effect. The value
1729 is passed in number of sessions per second sent to the SSL stack. It applies
1730 before the handshake in order to protect the stack against handshake abuses.
1731
Baptiste Assmann3749ebf2016-08-03 22:34:12 +02001732set server <backend>/<server> addr <ip4 or ip6 address> [port <port>]
Willy Tarreau44aed902015-10-13 14:45:29 +02001733 Replace the current IP address of a server by the one provided.
Michael Prokop4438c602019-05-24 10:25:45 +02001734 Optionally, the port can be changed using the 'port' parameter.
Baptiste Assmann3749ebf2016-08-03 22:34:12 +02001735 Note that changing the port also support switching from/to port mapping
1736 (notation with +X or -Y), only if a port is configured for the health check.
Willy Tarreau44aed902015-10-13 14:45:29 +02001737
1738set server <backend>/<server> agent [ up | down ]
1739 Force a server's agent to a new state. This can be useful to immediately
1740 switch a server's state regardless of some slow agent checks for example.
1741 Note that the change is propagated to tracking servers if any.
1742
Misiek43972902017-01-09 09:53:06 +01001743set server <backend>/<server> agent-addr <addr>
1744 Change addr for servers agent checks. Allows to migrate agent-checks to
1745 another address at runtime. You can specify both IP and hostname, it will be
1746 resolved.
1747
1748set server <backend>/<server> agent-send <value>
1749 Change agent string sent to agent check target. Allows to update string while
1750 changing server address to keep those two matching.
1751
Willy Tarreau44aed902015-10-13 14:45:29 +02001752set server <backend>/<server> health [ up | stopping | down ]
1753 Force a server's health to a new state. This can be useful to immediately
1754 switch a server's state regardless of some slow health checks for example.
1755 Note that the change is propagated to tracking servers if any.
1756
Baptiste Assmann50946562016-08-31 23:26:29 +02001757set server <backend>/<server> check-port <port>
1758 Change the port used for health checking to <port>
1759
Willy Tarreau44aed902015-10-13 14:45:29 +02001760set server <backend>/<server> state [ ready | drain | maint ]
1761 Force a server's administrative state to a new state. This can be useful to
1762 disable load balancing and/or any traffic to a server. Setting the state to
1763 "ready" puts the server in normal mode, and the command is the equivalent of
1764 the "enable server" command. Setting the state to "maint" disables any traffic
1765 to the server as well as any health checks. This is the equivalent of the
1766 "disable server" command. Setting the mode to "drain" only removes the server
1767 from load balancing but still allows it to be checked and to accept new
1768 persistent connections. Changes are propagated to tracking servers if any.
1769
1770set server <backend>/<server> weight <weight>[%]
1771 Change a server's weight to the value passed in argument. This is the exact
1772 equivalent of the "set weight" command below.
1773
Frédéric Lécailleb418c122017-04-26 11:24:02 +02001774set server <backend>/<server> fqdn <FQDN>
Lukas Tribusc5dd5a52018-08-14 11:39:35 +02001775 Change a server's FQDN to the value passed in argument. This requires the
1776 internal run-time DNS resolver to be configured and enabled for this server.
Frédéric Lécailleb418c122017-04-26 11:24:02 +02001777
Andjelko Iharosc4df59e2017-07-20 11:59:48 +02001778set severity-output [ none | number | string ]
1779 Change the severity output format of the stats socket connected to for the
1780 duration of the current session.
1781
Aurélien Nephtali1e0867c2018-04-18 14:04:58 +02001782set ssl ocsp-response <response | payload>
Willy Tarreau44aed902015-10-13 14:45:29 +02001783 This command is used to update an OCSP Response for a certificate (see "crt"
1784 on "bind" lines). Same controls are performed as during the initial loading of
1785 the response. The <response> must be passed as a base64 encoded string of the
Emmanuel Hocdet2c32d8f2017-05-22 14:58:00 +02001786 DER encoded response from the OCSP server. This command is not supported with
1787 BoringSSL.
Willy Tarreau44aed902015-10-13 14:45:29 +02001788
1789 Example:
1790 openssl ocsp -issuer issuer.pem -cert server.pem \
1791 -host ocsp.issuer.com:80 -respout resp.der
1792 echo "set ssl ocsp-response $(base64 -w 10000 resp.der)" | \
1793 socat stdio /var/run/haproxy.stat
1794
Aurélien Nephtali1e0867c2018-04-18 14:04:58 +02001795 using the payload syntax:
1796 echo -e "set ssl ocsp-response <<\n$(base64 resp.der)\n" | \
1797 socat stdio /var/run/haproxy.stat
1798
Willy Tarreau44aed902015-10-13 14:45:29 +02001799set ssl tls-key <id> <tlskey>
1800 Set the next TLS key for the <id> listener to <tlskey>. This key becomes the
1801 ultimate key, while the penultimate one is used for encryption (others just
1802 decrypt). The oldest TLS key present is overwritten. <id> is either a numeric
1803 #<id> or <file> returned by "show tls-keys". <tlskey> is a base64 encoded 48
Emeric Brun9e754772019-01-10 17:51:55 +01001804 or 80 bits TLS ticket key (ex. openssl rand 80 | openssl base64 -A).
Willy Tarreau44aed902015-10-13 14:45:29 +02001805
1806set table <table> key <key> [data.<data_type> <value>]*
1807 Create or update a stick-table entry in the table. If the key is not present,
1808 an entry is inserted. See stick-table in section 4.2 to find all possible
1809 values for <data_type>. The most likely use consists in dynamically entering
1810 entries for source IP addresses, with a flag in gpc0 to dynamically block an
1811 IP address or affect its quality of service. It is possible to pass multiple
1812 data_types in a single call.
1813
1814set timeout cli <delay>
1815 Change the CLI interface timeout for current connection. This can be useful
1816 during long debugging sessions where the user needs to constantly inspect
1817 some indicators without being disconnected. The delay is passed in seconds.
1818
1819set weight <backend>/<server> <weight>[%]
1820 Change a server's weight to the value passed in argument. If the value ends
1821 with the '%' sign, then the new weight will be relative to the initially
1822 configured weight. Absolute weights are permitted between 0 and 256.
1823 Relative weights must be positive with the resulting absolute weight is
1824 capped at 256. Servers which are part of a farm running a static
1825 load-balancing algorithm have stricter limitations because the weight
1826 cannot change once set. Thus for these servers, the only accepted values
1827 are 0 and 100% (or 0 and the initial weight). Changes take effect
1828 immediately, though certain LB algorithms require a certain amount of
1829 requests to consider changes. A typical usage of this command is to
1830 disable a server during an update by setting its weight to zero, then to
1831 enable it again after the update by setting it back to 100%. This command
1832 is restricted and can only be issued on sockets configured for level
1833 "admin". Both the backend and the server may be specified either by their
1834 name or by their numeric ID, prefixed with a sharp ('#').
1835
Willy Tarreaud6129fc2017-07-28 16:52:23 +02001836show acl [<acl>]
1837 Dump info about acl converters. Without argument, the list of all available
1838 acls is returned. If a <acl> is specified, its contents are dumped. <acl> if
1839 the #<id> or <file>. The dump format is the same than the map even for the
1840 sample value. The data returned are not a list of available ACL, but are the
1841 list of all patterns composing any ACL. Many of these patterns can be shared
1842 with maps.
1843
1844show backend
1845 Dump the list of backends available in the running process
1846
William Lallemand67a234f2018-12-13 09:05:45 +01001847show cli level
1848 Display the CLI level of the current CLI session. The result could be
1849 'admin', 'operator' or 'user'. See also the 'operator' and 'user' commands.
1850
1851 Example :
1852
1853 $ socat /tmp/sock1 readline
1854 prompt
1855 > operator
1856 > show cli level
1857 operator
1858 > user
1859 > show cli level
1860 user
1861 > operator
1862 Permission denied
1863
1864operator
1865 Decrease the CLI level of the current CLI session to operator. It can't be
Willy Tarreauabb9f9b2019-10-24 17:55:53 +02001866 increased. It also drops expert mode. See also "show cli level".
William Lallemand67a234f2018-12-13 09:05:45 +01001867
1868user
1869 Decrease the CLI level of the current CLI session to user. It can't be
Willy Tarreauabb9f9b2019-10-24 17:55:53 +02001870 increased. It also drops expert mode. See also "show cli level".
William Lallemand67a234f2018-12-13 09:05:45 +01001871
Willy Tarreau4c356932019-05-16 17:39:32 +02001872show activity
1873 Reports some counters about internal events that will help developers and
1874 more generally people who know haproxy well enough to narrow down the causes
1875 of reports of abnormal behaviours. A typical example would be a properly
1876 running process never sleeping and eating 100% of the CPU. The output fields
1877 will be made of one line per metric, and per-thread counters on the same
1878 line. These counters are 32-bit and will wrap during the process' life, which
1879 is not a problem since calls to this command will typically be performed
1880 twice. The fields are purposely not documented so that their exact meaning is
1881 verified in the code where the counters are fed. These values are also reset
1882 by the "clear counters" command.
1883
William Lallemand51132162016-12-16 16:38:58 +01001884show cli sockets
1885 List CLI sockets. The output format is composed of 3 fields separated by
1886 spaces. The first field is the socket address, it can be a unix socket, a
1887 ipv4 address:port couple or a ipv6 one. Socket of other types won't be dump.
1888 The second field describe the level of the socket: 'admin', 'user' or
1889 'operator'. The last field list the processes on which the socket is bound,
1890 separated by commas, it can be numbers or 'all'.
1891
1892 Example :
1893
1894 $ echo 'show cli sockets' | socat stdio /tmp/sock1
1895 # socket lvl processes
1896 /tmp/sock1 admin all
1897 127.0.0.1:9999 user 2,3,4
1898 127.0.0.2:9969 user 2
1899 [::1]:9999 operator 2
1900
William Lallemand86d0df02017-11-24 21:36:45 +01001901show cache
Cyril Bonté7b888f12017-11-26 22:24:31 +01001902 List the configured caches and the objects stored in each cache tree.
William Lallemand86d0df02017-11-24 21:36:45 +01001903
1904 $ echo 'show cache' | socat stdio /tmp/sock1
1905 0x7f6ac6c5b03a: foobar (shctx:0x7f6ac6c5b000, available blocks:3918)
1906 1 2 3 4
1907
1908 1. pointer to the cache structure
1909 2. cache name
1910 3. pointer to the mmap area (shctx)
1911 4. number of blocks available for reuse in the shctx
1912
1913 0x7f6ac6c5b4cc hash:286881868 size:39114 (39 blocks), refcount:9, expire:237
1914 1 2 3 4 5 6
1915
1916 1. pointer to the cache entry
1917 2. first 32 bits of the hash
1918 3. size of the object in bytes
1919 4. number of blocks used for the object
1920 5. number of transactions using the entry
1921 6. expiration time, can be negative if already expired
1922
Willy Tarreauae795722016-02-16 11:27:28 +01001923show env [<name>]
1924 Dump one or all environment variables known by the process. Without any
1925 argument, all variables are dumped. With an argument, only the specified
1926 variable is dumped if it exists. Otherwise "Variable not found" is emitted.
1927 Variables are dumped in the same format as they are stored or returned by the
1928 "env" utility, that is, "<name>=<value>". This can be handy when debugging
1929 certain configuration files making heavy use of environment variables to
1930 ensure that they contain the expected values. This command is restricted and
1931 can only be issued on sockets configured for levels "operator" or "admin".
1932
Willy Tarreau35069f82016-11-25 09:16:37 +01001933show errors [<iid>|<proxy>] [request|response]
Willy Tarreau44aed902015-10-13 14:45:29 +02001934 Dump last known request and response errors collected by frontends and
1935 backends. If <iid> is specified, the limit the dump to errors concerning
Willy Tarreau234ba2d2016-11-25 08:39:10 +01001936 either frontend or backend whose ID is <iid>. Proxy ID "-1" will cause
1937 all instances to be dumped. If a proxy name is specified instead, its ID
Willy Tarreau35069f82016-11-25 09:16:37 +01001938 will be used as the filter. If "request" or "response" is added after the
1939 proxy name or ID, only request or response errors will be dumped. This
1940 command is restricted and can only be issued on sockets configured for
1941 levels "operator" or "admin".
Willy Tarreau44aed902015-10-13 14:45:29 +02001942
1943 The errors which may be collected are the last request and response errors
1944 caused by protocol violations, often due to invalid characters in header
1945 names. The report precisely indicates what exact character violated the
1946 protocol. Other important information such as the exact date the error was
1947 detected, frontend and backend names, the server name (when known), the
1948 internal session ID and the source address which has initiated the session
1949 are reported too.
1950
1951 All characters are returned, and non-printable characters are encoded. The
1952 most common ones (\t = 9, \n = 10, \r = 13 and \e = 27) are encoded as one
1953 letter following a backslash. The backslash itself is encoded as '\\' to
1954 avoid confusion. Other non-printable characters are encoded '\xNN' where
1955 NN is the two-digits hexadecimal representation of the character's ASCII
1956 code.
1957
1958 Lines are prefixed with the position of their first character, starting at 0
1959 for the beginning of the buffer. At most one input line is printed per line,
1960 and large lines will be broken into multiple consecutive output lines so that
1961 the output never goes beyond 79 characters wide. It is easy to detect if a
1962 line was broken, because it will not end with '\n' and the next line's offset
1963 will be followed by a '+' sign, indicating it is a continuation of previous
1964 line.
1965
1966 Example :
Willy Tarreau35069f82016-11-25 09:16:37 +01001967 $ echo "show errors -1 response" | socat stdio /tmp/sock1
Willy Tarreau44aed902015-10-13 14:45:29 +02001968 >>> [04/Mar/2009:15:46:56.081] backend http-in (#2) : invalid response
1969 src 127.0.0.1, session #54, frontend fe-eth0 (#1), server s2 (#1)
1970 response length 213 bytes, error at position 23:
1971
1972 00000 HTTP/1.0 200 OK\r\n
1973 00017 header/bizarre:blah\r\n
1974 00038 Location: blah\r\n
1975 00054 Long-line: this is a very long line which should b
1976 00104+ e broken into multiple lines on the output buffer,
1977 00154+ otherwise it would be too large to print in a ter
1978 00204+ minal\r\n
1979 00211 \r\n
1980
1981 In the example above, we see that the backend "http-in" which has internal
1982 ID 2 has blocked an invalid response from its server s2 which has internal
1983 ID 1. The request was on session 54 initiated by source 127.0.0.1 and
1984 received by frontend fe-eth0 whose ID is 1. The total response length was
1985 213 bytes when the error was detected, and the error was at byte 23. This
1986 is the slash ('/') in header name "header/bizarre", which is not a valid
1987 HTTP character for a header name.
1988
Willy Tarreau1d181e42019-08-30 11:17:01 +02001989show events [<sink>] [-w] [-n]
Willy Tarreau9f830d72019-08-26 18:17:04 +02001990 With no option, this lists all known event sinks and their types. With an
1991 option, it will dump all available events in the designated sink if it is of
Willy Tarreau1d181e42019-08-30 11:17:01 +02001992 type buffer. If option "-w" is passed after the sink name, then once the end
1993 of the buffer is reached, the command will wait for new events and display
1994 them. It is possible to stop the operation by entering any input (which will
1995 be discarded) or by closing the session. Finally, option "-n" is used to
1996 directly seek to the end of the buffer, which is often convenient when
1997 combined with "-w" to only report new events. For convenience, "-wn" or "-nw"
1998 may be used to enable both options at once.
Willy Tarreau9f830d72019-08-26 18:17:04 +02001999
Willy Tarreau7a4a0ac2017-07-25 19:32:50 +02002000show fd [<fd>]
2001 Dump the list of either all open file descriptors or just the one number <fd>
2002 if specified. This is only aimed at developers who need to observe internal
2003 states in order to debug complex issues such as abnormal CPU usages. One fd
2004 is reported per lines, and for each of them, its state in the poller using
2005 upper case letters for enabled flags and lower case for disabled flags, using
2006 "P" for "polled", "R" for "ready", "A" for "active", the events status using
2007 "H" for "hangup", "E" for "error", "O" for "output", "P" for "priority" and
2008 "I" for "input", a few other flags like "N" for "new" (just added into the fd
2009 cache), "U" for "updated" (received an update in the fd cache), "L" for
2010 "linger_risk", "C" for "cloned", then the cached entry position, the pointer
2011 to the internal owner, the pointer to the I/O callback and its name when
2012 known. When the owner is a connection, the connection flags, and the target
2013 are reported (frontend, proxy or server). When the owner is a listener, the
2014 listener's state and its frontend are reported. There is no point in using
2015 this command without a good knowledge of the internals. It's worth noting
2016 that the output format may evolve over time so this output must not be parsed
2017 by tools designed to be durable.
2018
Willy Tarreau6b19b142019-10-09 15:44:21 +02002019show info [typed|json] [desc]
Willy Tarreau5d8b9792016-03-11 11:09:34 +01002020 Dump info about haproxy status on current process. If "typed" is passed as an
2021 optional argument, field numbers, names and types are emitted as well so that
2022 external monitoring products can easily retrieve, possibly aggregate, then
2023 report information found in fields they don't know. Each field is dumped on
Simon Horman05ee2132017-01-04 09:37:25 +01002024 its own line. If "json" is passed as an optional argument then
2025 information provided by "typed" output is provided in JSON format as a
2026 list of JSON objects. By default, the format contains only two columns
2027 delimited by a colon (':'). The left one is the field name and the right
2028 one is the value. It is very important to note that in typed output
2029 format, the dump for a single object is contiguous so that there is no
2030 need for a consumer to store everything at once.
Willy Tarreau5d8b9792016-03-11 11:09:34 +01002031
2032 When using the typed output format, each line is made of 4 columns delimited
2033 by colons (':'). The first column is a dot-delimited series of 3 elements. The
2034 first element is the numeric position of the field in the list (starting at
2035 zero). This position shall not change over time, but holes are to be expected,
2036 depending on build options or if some fields are deleted in the future. The
2037 second element is the field name as it appears in the default "show info"
2038 output. The third element is the relative process number starting at 1.
2039
2040 The rest of the line starting after the first colon follows the "typed output
2041 format" described in the section above. In short, the second column (after the
2042 first ':') indicates the origin, nature and scope of the variable. The third
2043 column indicates the type of the field, among "s32", "s64", "u32", "u64" and
2044 "str". Then the fourth column is the value itself, which the consumer knows
2045 how to parse thanks to column 3 and how to process thanks to column 2.
2046
2047 Thus the overall line format in typed mode is :
2048
2049 <field_pos>.<field_name>.<process_num>:<tags>:<type>:<value>
2050
Willy Tarreau6b19b142019-10-09 15:44:21 +02002051 When "desc" is appended to the command, one extra colon followed by a quoted
2052 string is appended with a description for the metric. At the time of writing,
2053 this is only supported for the "typed" and default output formats.
2054
Willy Tarreau5d8b9792016-03-11 11:09:34 +01002055 Example :
2056
2057 > show info
2058 Name: HAProxy
2059 Version: 1.7-dev1-de52ea-146
2060 Release_date: 2016/03/11
2061 Nbproc: 1
2062 Process_num: 1
2063 Pid: 28105
2064 Uptime: 0d 0h00m04s
2065 Uptime_sec: 4
2066 Memmax_MB: 0
2067 PoolAlloc_MB: 0
2068 PoolUsed_MB: 0
2069 PoolFailed: 0
2070 (...)
2071
2072 > show info typed
2073 0.Name.1:POS:str:HAProxy
2074 1.Version.1:POS:str:1.7-dev1-de52ea-146
2075 2.Release_date.1:POS:str:2016/03/11
2076 3.Nbproc.1:CGS:u32:1
2077 4.Process_num.1:KGP:u32:1
2078 5.Pid.1:SGP:u32:28105
2079 6.Uptime.1:MDP:str:0d 0h00m08s
2080 7.Uptime_sec.1:MDP:u32:8
2081 8.Memmax_MB.1:CLP:u32:0
2082 9.PoolAlloc_MB.1:MGP:u32:0
2083 10.PoolUsed_MB.1:MGP:u32:0
2084 11.PoolFailed.1:MCP:u32:0
2085 (...)
2086
Simon Horman1084a362016-11-21 17:00:24 +01002087 In the typed format, the presence of the process ID at the end of the
2088 first column makes it very easy to visually aggregate outputs from
2089 multiple processes.
Willy Tarreau5d8b9792016-03-11 11:09:34 +01002090 Example :
2091
2092 $ ( echo show info typed | socat /var/run/haproxy.sock1 ; \
2093 echo show info typed | socat /var/run/haproxy.sock2 ) | \
2094 sort -t . -k 1,1n -k 2,2 -k 3,3n
2095 0.Name.1:POS:str:HAProxy
2096 0.Name.2:POS:str:HAProxy
2097 1.Version.1:POS:str:1.7-dev1-868ab3-148
2098 1.Version.2:POS:str:1.7-dev1-868ab3-148
2099 2.Release_date.1:POS:str:2016/03/11
2100 2.Release_date.2:POS:str:2016/03/11
2101 3.Nbproc.1:CGS:u32:2
2102 3.Nbproc.2:CGS:u32:2
2103 4.Process_num.1:KGP:u32:1
2104 4.Process_num.2:KGP:u32:2
2105 5.Pid.1:SGP:u32:30120
2106 5.Pid.2:SGP:u32:30121
2107 6.Uptime.1:MDP:str:0d 0h01m28s
2108 6.Uptime.2:MDP:str:0d 0h01m28s
2109 (...)
Willy Tarreau44aed902015-10-13 14:45:29 +02002110
Simon Horman05ee2132017-01-04 09:37:25 +01002111 The format of JSON output is described in a schema which may be output
Simon Horman6f6bb382017-01-04 09:37:26 +01002112 using "show schema json".
Simon Horman05ee2132017-01-04 09:37:25 +01002113
2114 The JSON output contains no extra whitespace in order to reduce the
2115 volume of output. For human consumption passing the output through a
2116 pretty printer may be helpful. Example :
2117
2118 $ echo "show info json" | socat /var/run/haproxy.sock stdio | \
2119 python -m json.tool
2120
Simon Horman6f6bb382017-01-04 09:37:26 +01002121 The JSON output contains no extra whitespace in order to reduce the
2122 volume of output. For human consumption passing the output through a
2123 pretty printer may be helpful. Example :
2124
2125 $ echo "show info json" | socat /var/run/haproxy.sock stdio | \
2126 python -m json.tool
2127
Willy Tarreau44aed902015-10-13 14:45:29 +02002128show map [<map>]
2129 Dump info about map converters. Without argument, the list of all available
2130 maps is returned. If a <map> is specified, its contents are dumped. <map> is
2131 the #<id> or <file>. The first column is a unique identifier. It can be used
2132 as reference for the operation "del map" and "set map". The second column is
2133 the pattern and the third column is the sample if available. The data returned
2134 are not directly a list of available maps, but are the list of all patterns
2135 composing any map. Many of these patterns can be shared with ACL.
2136
Frédéric Lécaille21dde502019-04-15 13:50:23 +02002137show peers [<peers section>]
2138 Dump info about the peers configured in "peers" sections. Without argument,
2139 the list of the peers belonging to all the "peers" sections are listed. If
2140 <peers section> is specified, only the information about the peers belonging
2141 to this "peers" section are dumped.
2142
Michael Prokop4438c602019-05-24 10:25:45 +02002143 Here are two examples of outputs where hostA, hostB and hostC peers belong to
Frédéric Lécaille21dde502019-04-15 13:50:23 +02002144 "sharedlb" peers sections. Only hostA and hostB are connected. Only hostA has
2145 sent data to hostB.
2146
2147 $ echo "show peers" | socat - /tmp/hostA
2148 0x55deb0224320: [15/Apr/2019:11:28:01] id=sharedlb state=0 flags=0x3 \
Emeric Brun0bbec0f2019-04-18 11:39:43 +02002149 resync_timeout=<PAST> task_calls=45122
Frédéric Lécaille21dde502019-04-15 13:50:23 +02002150 0x55deb022b540: id=hostC(remote) addr=127.0.0.12:10002 status=CONN \
2151 reconnect=4s confirm=0
2152 flags=0x0
2153 0x55deb022a440: id=hostA(local) addr=127.0.0.10:10000 status=NONE \
2154 reconnect=<NEVER> confirm=0
2155 flags=0x0
2156 0x55deb0227d70: id=hostB(remote) addr=127.0.0.11:10001 status=ESTA
2157 reconnect=2s confirm=0
Emeric Brun0bbec0f2019-04-18 11:39:43 +02002158 flags=0x20000200 appctx:0x55deb028fba0 st0=7 st1=0 task_calls=14456 \
2159 state=EST
Frédéric Lécaille21dde502019-04-15 13:50:23 +02002160 xprt=RAW src=127.0.0.1:37257 addr=127.0.0.10:10000
2161 remote_table:0x55deb0224a10 id=stkt local_id=1 remote_id=1
2162 last_local_table:0x55deb0224a10 id=stkt local_id=1 remote_id=1
2163 shared tables:
2164 0x55deb0224a10 local_id=1 remote_id=1 flags=0x0 remote_data=0x65
2165 last_acked=0 last_pushed=3 last_get=0 teaching_origin=0 update=3
2166 table:0x55deb022d6a0 id=stkt update=3 localupdate=3 \
2167 commitupdate=3 syncing=0
2168
2169 $ echo "show peers" | socat - /tmp/hostB
2170 0x55871b5ab320: [15/Apr/2019:11:28:03] id=sharedlb state=0 flags=0x3 \
Emeric Brun0bbec0f2019-04-18 11:39:43 +02002171 resync_timeout=<PAST> task_calls=3
Frédéric Lécaille21dde502019-04-15 13:50:23 +02002172 0x55871b5b2540: id=hostC(remote) addr=127.0.0.12:10002 status=CONN \
2173 reconnect=3s confirm=0
2174 flags=0x0
2175 0x55871b5b1440: id=hostB(local) addr=127.0.0.11:10001 status=NONE \
2176 reconnect=<NEVER> confirm=0
2177 flags=0x0
2178 0x55871b5aed70: id=hostA(remote) addr=127.0.0.10:10000 status=ESTA \
2179 reconnect=2s confirm=0
Emeric Brun0bbec0f2019-04-18 11:39:43 +02002180 flags=0x20000200 appctx:0x7fa46800ee00 st0=7 st1=0 task_calls=62356 \
2181 state=EST
Frédéric Lécaille21dde502019-04-15 13:50:23 +02002182 remote_table:0x55871b5ab960 id=stkt local_id=1 remote_id=1
2183 last_local_table:0x55871b5ab960 id=stkt local_id=1 remote_id=1
2184 shared tables:
2185 0x55871b5ab960 local_id=1 remote_id=1 flags=0x0 remote_data=0x65
2186 last_acked=3 last_pushed=0 last_get=3 teaching_origin=0 update=0
2187 table:0x55871b5b46a0 id=stkt update=1 localupdate=0 \
2188 commitupdate=0 syncing=0
2189
Willy Tarreau44aed902015-10-13 14:45:29 +02002190show pools
2191 Dump the status of internal memory pools. This is useful to track memory
2192 usage when suspecting a memory leak for example. It does exactly the same
2193 as the SIGQUIT when running in foreground except that it does not flush
2194 the pools.
2195
Willy Tarreau75c62c22018-11-22 11:02:09 +01002196show profiling
2197 Dumps the current profiling settings, one per line, as well as the command
2198 needed to change them.
2199
Willy Tarreau44aed902015-10-13 14:45:29 +02002200show servers state [<backend>]
2201 Dump the state of the servers found in the running configuration. A backend
2202 name or identifier may be provided to limit the output to this backend only.
2203
2204 The dump has the following format:
2205 - first line contains the format version (1 in this specification);
2206 - second line contains the column headers, prefixed by a sharp ('#');
2207 - third line and next ones contain data;
2208 - each line starting by a sharp ('#') is considered as a comment.
2209
Dan Lloyd8e48b872016-07-01 21:01:18 -04002210 Since multiple versions of the output may co-exist, below is the list of
Willy Tarreau44aed902015-10-13 14:45:29 +02002211 fields and their order per file format version :
2212 1:
2213 be_id: Backend unique id.
2214 be_name: Backend label.
2215 srv_id: Server unique id (in the backend).
2216 srv_name: Server label.
2217 srv_addr: Server IP address.
2218 srv_op_state: Server operational state (UP/DOWN/...).
Cyril Bonté5b2ce8a2016-11-02 00:19:58 +01002219 0 = SRV_ST_STOPPED
2220 The server is down.
2221 1 = SRV_ST_STARTING
2222 The server is warming up (up but
2223 throttled).
2224 2 = SRV_ST_RUNNING
2225 The server is fully up.
2226 3 = SRV_ST_STOPPING
2227 The server is up but soft-stopping
2228 (eg: 404).
Willy Tarreau44aed902015-10-13 14:45:29 +02002229 srv_admin_state: Server administrative state (MAINT/DRAIN/...).
Cyril Bonté5b2ce8a2016-11-02 00:19:58 +01002230 The state is actually a mask of values :
2231 0x01 = SRV_ADMF_FMAINT
2232 The server was explicitly forced into
2233 maintenance.
2234 0x02 = SRV_ADMF_IMAINT
2235 The server has inherited the maintenance
2236 status from a tracked server.
2237 0x04 = SRV_ADMF_CMAINT
2238 The server is in maintenance because of
2239 the configuration.
2240 0x08 = SRV_ADMF_FDRAIN
2241 The server was explicitly forced into
2242 drain state.
2243 0x10 = SRV_ADMF_IDRAIN
2244 The server has inherited the drain status
2245 from a tracked server.
Baptiste Assmann89aa7f32016-11-02 21:31:27 +01002246 0x20 = SRV_ADMF_RMAINT
2247 The server is in maintenance because of an
2248 IP address resolution failure.
Frédéric Lécailleb418c122017-04-26 11:24:02 +02002249 0x40 = SRV_ADMF_HMAINT
2250 The server FQDN was set from stats socket.
2251
Willy Tarreau44aed902015-10-13 14:45:29 +02002252 srv_uweight: User visible server's weight.
2253 srv_iweight: Server's initial weight.
2254 srv_time_since_last_change: Time since last operational change.
2255 srv_check_status: Last health check status.
2256 srv_check_result: Last check result (FAILED/PASSED/...).
Cyril Bonté5b2ce8a2016-11-02 00:19:58 +01002257 0 = CHK_RES_UNKNOWN
2258 Initialized to this by default.
2259 1 = CHK_RES_NEUTRAL
2260 Valid check but no status information.
2261 2 = CHK_RES_FAILED
2262 Check failed.
2263 3 = CHK_RES_PASSED
2264 Check succeeded and server is fully up
2265 again.
2266 4 = CHK_RES_CONDPASS
2267 Check reports the server doesn't want new
2268 sessions.
Willy Tarreau44aed902015-10-13 14:45:29 +02002269 srv_check_health: Checks rise / fall current counter.
2270 srv_check_state: State of the check (ENABLED/PAUSED/...).
Cyril Bonté5b2ce8a2016-11-02 00:19:58 +01002271 The state is actually a mask of values :
2272 0x01 = CHK_ST_INPROGRESS
2273 A check is currently running.
2274 0x02 = CHK_ST_CONFIGURED
2275 This check is configured and may be
2276 enabled.
2277 0x04 = CHK_ST_ENABLED
2278 This check is currently administratively
2279 enabled.
2280 0x08 = CHK_ST_PAUSED
2281 Checks are paused because of maintenance
2282 (health only).
Willy Tarreau44aed902015-10-13 14:45:29 +02002283 srv_agent_state: State of the agent check (ENABLED/PAUSED/...).
Cyril Bonté5b2ce8a2016-11-02 00:19:58 +01002284 This state uses the same mask values as
2285 "srv_check_state", adding this specific one :
2286 0x10 = CHK_ST_AGENT
2287 Check is an agent check (otherwise it's a
2288 health check).
Willy Tarreau44aed902015-10-13 14:45:29 +02002289 bk_f_forced_id: Flag to know if the backend ID is forced by
2290 configuration.
2291 srv_f_forced_id: Flag to know if the server's ID is forced by
2292 configuration.
Frédéric Lécailleb418c122017-04-26 11:24:02 +02002293 srv_fqdn: Server FQDN.
Frédéric Lécaille31694712017-08-01 08:47:19 +02002294 srv_port: Server port.
Baptiste Assmann6d0f38f2018-07-02 17:00:54 +02002295 srvrecord: DNS SRV record associated to this SRV.
Willy Tarreau44aed902015-10-13 14:45:29 +02002296
2297show sess
2298 Dump all known sessions. Avoid doing this on slow connections as this can
2299 be huge. This command is restricted and can only be issued on sockets
2300 configured for levels "operator" or "admin".
2301
2302show sess <id>
2303 Display a lot of internal information about the specified session identifier.
2304 This identifier is the first field at the beginning of the lines in the dumps
2305 of "show sess" (it corresponds to the session pointer). Those information are
2306 useless to most users but may be used by haproxy developers to troubleshoot a
2307 complex bug. The output format is intentionally not documented so that it can
2308 freely evolve depending on demands. You may find a description of all fields
2309 returned in src/dumpstats.c
2310
2311 The special id "all" dumps the states of all sessions, which must be avoided
2312 as much as possible as it is highly CPU intensive and can take a lot of time.
2313
Willy Tarreau6b19b142019-10-09 15:44:21 +02002314show stat [{<iid>|<proxy>} <type> <sid>] [typed|json] [desc]
Simon Horman05ee2132017-01-04 09:37:25 +01002315 Dump statistics using the CSV format; using the extended typed output
2316 format described in the section above if "typed" is passed after the
2317 other arguments; or in JSON if "json" is passed after the other arguments
2318 . By passing <id>, <type> and <sid>, it is possible to dump only selected
2319 items :
Willy Tarreaua1b1ed52016-11-25 08:50:58 +01002320 - <iid> is a proxy ID, -1 to dump everything. Alternatively, a proxy name
2321 <proxy> may be specified. In this case, this proxy's ID will be used as
2322 the ID selector.
Willy Tarreau44aed902015-10-13 14:45:29 +02002323 - <type> selects the type of dumpable objects : 1 for frontends, 2 for
2324 backends, 4 for servers, -1 for everything. These values can be ORed,
2325 for example:
2326 1 + 2 = 3 -> frontend + backend.
2327 1 + 2 + 4 = 7 -> frontend + backend + server.
2328 - <sid> is a server ID, -1 to dump everything from the selected proxy.
2329
2330 Example :
2331 $ echo "show info;show stat" | socat stdio unix-connect:/tmp/sock1
2332 >>> Name: HAProxy
2333 Version: 1.4-dev2-49
2334 Release_date: 2009/09/23
2335 Nbproc: 1
2336 Process_num: 1
2337 (...)
2338
2339 # pxname,svname,qcur,qmax,scur,smax,slim,stot,bin,bout,dreq, (...)
2340 stats,FRONTEND,,,0,0,1000,0,0,0,0,0,0,,,,,OPEN,,,,,,,,,1,1,0, (...)
2341 stats,BACKEND,0,0,0,0,1000,0,0,0,0,0,,0,0,0,0,UP,0,0,0,,0,250,(...)
2342 (...)
2343 www1,BACKEND,0,0,0,0,1000,0,0,0,0,0,,0,0,0,0,UP,1,1,0,,0,250, (...)
2344
2345 $
2346
Willy Tarreau5d8b9792016-03-11 11:09:34 +01002347 In this example, two commands have been issued at once. That way it's easy to
2348 find which process the stats apply to in multi-process mode. This is not
2349 needed in the typed output format as the process number is reported on each
2350 line. Notice the empty line after the information output which marks the end
2351 of the first block. A similar empty line appears at the end of the second
2352 block (stats) so that the reader knows the output has not been truncated.
2353
2354 When "typed" is specified, the output format is more suitable to monitoring
2355 tools because it provides numeric positions and indicates the type of each
2356 output field. Each value stands on its own line with process number, element
2357 number, nature, origin and scope. This same format is available via the HTTP
2358 stats by passing ";typed" after the URI. It is very important to note that in
Dan Lloyd8e48b872016-07-01 21:01:18 -04002359 typed output format, the dump for a single object is contiguous so that there
Willy Tarreau5d8b9792016-03-11 11:09:34 +01002360 is no need for a consumer to store everything at once.
2361
2362 When using the typed output format, each line is made of 4 columns delimited
2363 by colons (':'). The first column is a dot-delimited series of 5 elements. The
2364 first element is a letter indicating the type of the object being described.
2365 At the moment the following object types are known : 'F' for a frontend, 'B'
2366 for a backend, 'L' for a listener, and 'S' for a server. The second element
2367 The second element is a positive integer representing the unique identifier of
2368 the proxy the object belongs to. It is equivalent to the "iid" column of the
2369 CSV output and matches the value in front of the optional "id" directive found
2370 in the frontend or backend section. The third element is a positive integer
2371 containing the unique object identifier inside the proxy, and corresponds to
2372 the "sid" column of the CSV output. ID 0 is reported when dumping a frontend
2373 or a backend. For a listener or a server, this corresponds to their respective
2374 ID inside the proxy. The fourth element is the numeric position of the field
2375 in the list (starting at zero). This position shall not change over time, but
2376 holes are to be expected, depending on build options or if some fields are
2377 deleted in the future. The fifth element is the field name as it appears in
2378 the CSV output. The sixth element is a positive integer and is the relative
2379 process number starting at 1.
2380
2381 The rest of the line starting after the first colon follows the "typed output
2382 format" described in the section above. In short, the second column (after the
2383 first ':') indicates the origin, nature and scope of the variable. The third
2384 column indicates the type of the field, among "s32", "s64", "u32", "u64" and
2385 "str". Then the fourth column is the value itself, which the consumer knows
2386 how to parse thanks to column 3 and how to process thanks to column 2.
2387
Willy Tarreau6b19b142019-10-09 15:44:21 +02002388 When "desc" is appended to the command, one extra colon followed by a quoted
2389 string is appended with a description for the metric. At the time of writing,
2390 this is only supported for the "typed" output format.
2391
Willy Tarreau5d8b9792016-03-11 11:09:34 +01002392 Thus the overall line format in typed mode is :
2393
2394 <obj>.<px_id>.<id>.<fpos>.<fname>.<process_num>:<tags>:<type>:<value>
2395
2396 Here's an example of typed output format :
2397
2398 $ echo "show stat typed" | socat stdio unix-connect:/tmp/sock1
2399 F.2.0.0.pxname.1:MGP:str:private-frontend
2400 F.2.0.1.svname.1:MGP:str:FRONTEND
2401 F.2.0.8.bin.1:MGP:u64:0
2402 F.2.0.9.bout.1:MGP:u64:0
2403 F.2.0.40.hrsp_2xx.1:MGP:u64:0
2404 L.2.1.0.pxname.1:MGP:str:private-frontend
2405 L.2.1.1.svname.1:MGP:str:sock-1
2406 L.2.1.17.status.1:MGP:str:OPEN
2407 L.2.1.73.addr.1:MGP:str:0.0.0.0:8001
2408 S.3.13.60.rtime.1:MCP:u32:0
2409 S.3.13.61.ttime.1:MCP:u32:0
2410 S.3.13.62.agent_status.1:MGP:str:L4TOUT
2411 S.3.13.64.agent_duration.1:MGP:u64:2001
2412 S.3.13.65.check_desc.1:MCP:str:Layer4 timeout
2413 S.3.13.66.agent_desc.1:MCP:str:Layer4 timeout
2414 S.3.13.67.check_rise.1:MCP:u32:2
2415 S.3.13.68.check_fall.1:MCP:u32:3
2416 S.3.13.69.check_health.1:SGP:u32:0
2417 S.3.13.70.agent_rise.1:MaP:u32:1
2418 S.3.13.71.agent_fall.1:SGP:u32:1
2419 S.3.13.72.agent_health.1:SGP:u32:1
2420 S.3.13.73.addr.1:MCP:str:1.255.255.255:8888
2421 S.3.13.75.mode.1:MAP:str:http
2422 B.3.0.0.pxname.1:MGP:str:private-backend
2423 B.3.0.1.svname.1:MGP:str:BACKEND
2424 B.3.0.2.qcur.1:MGP:u32:0
2425 B.3.0.3.qmax.1:MGP:u32:0
2426 B.3.0.4.scur.1:MGP:u32:0
2427 B.3.0.5.smax.1:MGP:u32:0
2428 B.3.0.6.slim.1:MGP:u32:1000
2429 B.3.0.55.lastsess.1:MMP:s32:-1
2430 (...)
2431
Simon Horman1084a362016-11-21 17:00:24 +01002432 In the typed format, the presence of the process ID at the end of the
2433 first column makes it very easy to visually aggregate outputs from
2434 multiple processes, as show in the example below where each line appears
2435 for each process :
Willy Tarreau5d8b9792016-03-11 11:09:34 +01002436
2437 $ ( echo show stat typed | socat /var/run/haproxy.sock1 - ; \
2438 echo show stat typed | socat /var/run/haproxy.sock2 - ) | \
2439 sort -t . -k 1,1 -k 2,2n -k 3,3n -k 4,4n -k 5,5 -k 6,6n
2440 B.3.0.0.pxname.1:MGP:str:private-backend
2441 B.3.0.0.pxname.2:MGP:str:private-backend
2442 B.3.0.1.svname.1:MGP:str:BACKEND
2443 B.3.0.1.svname.2:MGP:str:BACKEND
2444 B.3.0.2.qcur.1:MGP:u32:0
2445 B.3.0.2.qcur.2:MGP:u32:0
2446 B.3.0.3.qmax.1:MGP:u32:0
2447 B.3.0.3.qmax.2:MGP:u32:0
2448 B.3.0.4.scur.1:MGP:u32:0
2449 B.3.0.4.scur.2:MGP:u32:0
2450 B.3.0.5.smax.1:MGP:u32:0
2451 B.3.0.5.smax.2:MGP:u32:0
2452 B.3.0.6.slim.1:MGP:u32:1000
2453 B.3.0.6.slim.2:MGP:u32:1000
2454 (...)
Willy Tarreau44aed902015-10-13 14:45:29 +02002455
Simon Horman05ee2132017-01-04 09:37:25 +01002456 The format of JSON output is described in a schema which may be output
Simon Horman6f6bb382017-01-04 09:37:26 +01002457 using "show schema json".
2458
2459 The JSON output contains no extra whitespace in order to reduce the
2460 volume of output. For human consumption passing the output through a
2461 pretty printer may be helpful. Example :
2462
2463 $ echo "show stat json" | socat /var/run/haproxy.sock stdio | \
2464 python -m json.tool
Simon Horman05ee2132017-01-04 09:37:25 +01002465
2466 The JSON output contains no extra whitespace in order to reduce the
2467 volume of output. For human consumption passing the output through a
2468 pretty printer may be helpful. Example :
2469
2470 $ echo "show stat json" | socat /var/run/haproxy.sock stdio | \
2471 python -m json.tool
2472
Christopher Faulet78c43062019-09-27 10:45:47 +02002473show resolvers [<resolvers section id>]
Willy Tarreau44aed902015-10-13 14:45:29 +02002474 Dump statistics for the given resolvers section, or all resolvers sections
2475 if no section is supplied.
2476
2477 For each name server, the following counters are reported:
2478 sent: number of DNS requests sent to this server
2479 valid: number of DNS valid responses received from this server
2480 update: number of DNS responses used to update the server's IP address
2481 cname: number of CNAME responses
2482 cname_error: CNAME errors encountered with this server
2483 any_err: number of empty response (IE: server does not support ANY type)
2484 nx: non existent domain response received from this server
2485 timeout: how many time this server did not answer in time
2486 refused: number of requests refused by this server
2487 other: any other DNS errors
2488 invalid: invalid DNS response (from a protocol point of view)
2489 too_big: too big response
2490 outdated: number of response arrived too late (after an other name server)
2491
2492show table
2493 Dump general information on all known stick-tables. Their name is returned
2494 (the name of the proxy which holds them), their type (currently zero, always
2495 IP), their size in maximum possible number of entries, and the number of
2496 entries currently in use.
2497
2498 Example :
2499 $ echo "show table" | socat stdio /tmp/sock1
2500 >>> # table: front_pub, type: ip, size:204800, used:171454
2501 >>> # table: back_rdp, type: ip, size:204800, used:0
2502
2503show table <name> [ data.<type> <operator> <value> ] | [ key <key> ]
2504 Dump contents of stick-table <name>. In this mode, a first line of generic
2505 information about the table is reported as with "show table", then all
2506 entries are dumped. Since this can be quite heavy, it is possible to specify
2507 a filter in order to specify what entries to display.
2508
2509 When the "data." form is used the filter applies to the stored data (see
2510 "stick-table" in section 4.2). A stored data type must be specified
2511 in <type>, and this data type must be stored in the table otherwise an
2512 error is reported. The data is compared according to <operator> with the
2513 64-bit integer <value>. Operators are the same as with the ACLs :
2514
2515 - eq : match entries whose data is equal to this value
2516 - ne : match entries whose data is not equal to this value
2517 - le : match entries whose data is less than or equal to this value
2518 - ge : match entries whose data is greater than or equal to this value
2519 - lt : match entries whose data is less than this value
2520 - gt : match entries whose data is greater than this value
2521
2522
2523 When the key form is used the entry <key> is shown. The key must be of the
2524 same type as the table, which currently is limited to IPv4, IPv6, integer,
2525 and string.
2526
2527 Example :
2528 $ echo "show table http_proxy" | socat stdio /tmp/sock1
2529 >>> # table: http_proxy, type: ip, size:204800, used:2
2530 >>> 0x80e6a4c: key=127.0.0.1 use=0 exp=3594729 gpc0=0 conn_rate(30000)=1 \
2531 bytes_out_rate(60000)=187
2532 >>> 0x80e6a80: key=127.0.0.2 use=0 exp=3594740 gpc0=1 conn_rate(30000)=10 \
2533 bytes_out_rate(60000)=191
2534
2535 $ echo "show table http_proxy data.gpc0 gt 0" | socat stdio /tmp/sock1
2536 >>> # table: http_proxy, type: ip, size:204800, used:2
2537 >>> 0x80e6a80: key=127.0.0.2 use=0 exp=3594740 gpc0=1 conn_rate(30000)=10 \
2538 bytes_out_rate(60000)=191
2539
2540 $ echo "show table http_proxy data.conn_rate gt 5" | \
2541 socat stdio /tmp/sock1
2542 >>> # table: http_proxy, type: ip, size:204800, used:2
2543 >>> 0x80e6a80: key=127.0.0.2 use=0 exp=3594740 gpc0=1 conn_rate(30000)=10 \
2544 bytes_out_rate(60000)=191
2545
2546 $ echo "show table http_proxy key 127.0.0.2" | \
2547 socat stdio /tmp/sock1
2548 >>> # table: http_proxy, type: ip, size:204800, used:2
2549 >>> 0x80e6a80: key=127.0.0.2 use=0 exp=3594740 gpc0=1 conn_rate(30000)=10 \
2550 bytes_out_rate(60000)=191
2551
2552 When the data criterion applies to a dynamic value dependent on time such as
2553 a bytes rate, the value is dynamically computed during the evaluation of the
2554 entry in order to decide whether it has to be dumped or not. This means that
2555 such a filter could match for some time then not match anymore because as
2556 time goes, the average event rate drops.
2557
2558 It is possible to use this to extract lists of IP addresses abusing the
2559 service, in order to monitor them or even blacklist them in a firewall.
2560 Example :
2561 $ echo "show table http_proxy data.gpc0 gt 0" \
2562 | socat stdio /tmp/sock1 \
2563 | fgrep 'key=' | cut -d' ' -f2 | cut -d= -f2 > abusers-ip.txt
2564 ( or | awk '/key/{ print a[split($2,a,"=")]; }' )
2565
Willy Tarreau4e2b6462019-05-16 17:44:30 +02002566show threads
2567 Dumps some internal states and structures for each thread, that may be useful
2568 to help developers understand a problem. The output tries to be readable by
Willy Tarreauc7091d82019-05-17 10:08:49 +02002569 showing one block per thread. When haproxy is built with USE_THREAD_DUMP=1,
2570 an advanced dump mechanism involving thread signals is used so that each
2571 thread can dump its own state in turn. Without this option, the thread
2572 processing the command shows all its details but the other ones are less
Willy Tarreaue6a02fa2019-05-22 07:06:44 +02002573 detailed. A star ('*') is displayed in front of the thread handling the
2574 command. A right angle bracket ('>') may also be displayed in front of
2575 threads which didn't make any progress since last invocation of this command,
2576 indicating a bug in the code which must absolutely be reported. When this
2577 happens between two threads it usually indicates a deadlock. If a thread is
2578 alone, it's a different bug like a corrupted list. In all cases the process
2579 needs is not fully functional anymore and needs to be restarted.
2580
2581 The output format is purposely not documented so that it can easily evolve as
2582 new needs are identified, without having to maintain any form of backwards
2583 compatibility, and just like with "show activity", the values are meaningless
2584 without the code at hand.
Willy Tarreau4e2b6462019-05-16 17:44:30 +02002585
William Lallemandbb933462016-05-31 21:09:53 +02002586show tls-keys [id|*]
2587 Dump all loaded TLS ticket keys references. The TLS ticket key reference ID
2588 and the file from which the keys have been loaded is shown. Both of those
2589 can be used to update the TLS keys using "set ssl tls-key". If an ID is
2590 specified as parameter, it will dump the tickets, using * it will dump every
2591 keys from every references.
Willy Tarreau44aed902015-10-13 14:45:29 +02002592
Simon Horman6f6bb382017-01-04 09:37:26 +01002593show schema json
2594 Dump the schema used for the output of "show info json" and "show stat json".
2595
2596 The contains no extra whitespace in order to reduce the volume of output.
2597 For human consumption passing the output through a pretty printer may be
2598 helpful. Example :
2599
2600 $ echo "show schema json" | socat /var/run/haproxy.sock stdio | \
2601 python -m json.tool
2602
2603 The schema follows "JSON Schema" (json-schema.org) and accordingly
2604 verifiers may be used to verify the output of "show info json" and "show
2605 stat json" against the schema.
2606
Willy Tarreauf909c912019-08-22 20:06:04 +02002607show trace [<source>]
2608 Show the current trace status. For each source a line is displayed with a
2609 single-character status indicating if the trace is stopped, waiting, or
2610 running. The output sink used by the trace is indicated (or "none" if none
2611 was set), as well as the number of dropped events in this sink, followed by a
2612 brief description of the source. If a source name is specified, a detailed
2613 list of all events supported by the source, and their status for each action
2614 (report, start, pause, stop), indicated by a "+" if they are enabled, or a
2615 "-" otherwise. All these events are independent and an event might trigger
2616 a start without being reported and conversely.
Simon Horman6f6bb382017-01-04 09:37:26 +01002617
Willy Tarreau44aed902015-10-13 14:45:29 +02002618shutdown frontend <frontend>
2619 Completely delete the specified frontend. All the ports it was bound to will
2620 be released. It will not be possible to enable the frontend anymore after
2621 this operation. This is intended to be used in environments where stopping a
2622 proxy is not even imaginable but a misconfigured proxy must be fixed. That
2623 way it's possible to release the port and bind it into another process to
2624 restore operations. The frontend will not appear at all on the stats page
2625 once it is terminated.
2626
2627 The frontend may be specified either by its name or by its numeric ID,
2628 prefixed with a sharp ('#').
2629
2630 This command is restricted and can only be issued on sockets configured for
2631 level "admin".
2632
2633shutdown session <id>
2634 Immediately terminate the session matching the specified session identifier.
2635 This identifier is the first field at the beginning of the lines in the dumps
2636 of "show sess" (it corresponds to the session pointer). This can be used to
2637 terminate a long-running session without waiting for a timeout or when an
2638 endless transfer is ongoing. Such terminated sessions are reported with a 'K'
2639 flag in the logs.
2640
2641shutdown sessions server <backend>/<server>
2642 Immediately terminate all the sessions attached to the specified server. This
2643 can be used to terminate long-running sessions after a server is put into
2644 maintenance mode, for instance. Such terminated sessions are reported with a
2645 'K' flag in the logs.
2646
Willy Tarreauf909c912019-08-22 20:06:04 +02002647trace
2648 The "trace" command alone lists the trace sources, their current status, and
2649 their brief descriptions. It is only meant as a menu to enter next levels,
2650 see other "trace" commands below.
2651
2652trace 0
2653 Immediately stops all traces. This is made to be used as a quick solution
2654 to terminate a debugging session or as an emergency action to be used in case
2655 complex traces were enabled on multiple sources and impact the service.
2656
2657trace <source> event [ [+|-|!]<name> ]
2658 Without argument, this will list all the events supported by the designated
2659 source. They are prefixed with a "-" if they are not enabled, or a "+" if
2660 they are enabled. It is important to note that a single trace may be labelled
2661 with multiple events, and as long as any of the enabled events matches one of
2662 the events labelled on the trace, the event will be passed to the trace
2663 subsystem. For example, receiving an HTTP/2 frame of type HEADERS may trigger
2664 a frame event and a stream event since the frame creates a new stream. If
2665 either the frame event or the stream event are enabled for this source, the
2666 frame will be passed to the trace framework.
2667
2668 With an argument, it is possible to toggle the state of each event and
2669 individually enable or disable them. Two special keywords are supported,
2670 "none", which matches no event, and is used to disable all events at once,
2671 and "any" which matches all events, and is used to enable all events at
2672 once. Other events are specific to the event source. It is possible to
2673 enable one event by specifying its name, optionally prefixed with '+' for
2674 better readability. It is possible to disable one event by specifying its
2675 name prefixed by a '-' or a '!'.
2676
2677 One way to completely disable a trace source is to pass "event none", and
2678 this source will instantly be totally ignored.
2679
2680trace <source> level [<level>]
Willy Tarreau2ea549b2019-08-29 08:01:48 +02002681 Without argument, this will list all trace levels for this source, and the
Willy Tarreauf909c912019-08-22 20:06:04 +02002682 current one will be indicated by a star ('*') prepended in front of it. With
Willy Tarreau2ea549b2019-08-29 08:01:48 +02002683 an argument, this will change the trace level to the specified level. Detail
Willy Tarreauf909c912019-08-22 20:06:04 +02002684 levels are a form of filters that are applied before reporting the events.
Willy Tarreau2ea549b2019-08-29 08:01:48 +02002685 These filters are used to selectively include or exclude events depending on
2686 their level of importance. For example a developer might need to know
2687 precisely where in the code an HTTP header was considered invalid while the
2688 end user may not even care about this header's validity at all. There are
2689 currently 5 distinct levels for a trace :
Willy Tarreauf909c912019-08-22 20:06:04 +02002690
2691 user this will report information that are suitable for use by a
2692 regular haproxy user who wants to observe his traffic.
2693 Typically some HTTP requests and responses will be reported
2694 without much detail. Most sources will set this as the
2695 default level to ease operations.
2696
Willy Tarreau2ea549b2019-08-29 08:01:48 +02002697 proto in addition to what is reported at the "user" level, it also
2698 displays protocol-level updates. This can for example be the
2699 frame types or HTTP headers after decoding.
Willy Tarreauf909c912019-08-22 20:06:04 +02002700
2701 state in addition to what is reported at the "proto" level, it
2702 will also display state transitions (or failed transitions)
2703 which happen in parsers, so this will show attempts to
2704 perform an operation while the "proto" level only shows
2705 the final operation.
2706
Willy Tarreau2ea549b2019-08-29 08:01:48 +02002707 data in addition to what is reported at the "state" level, it
2708 will also include data transfers between the various layers.
2709
Willy Tarreauf909c912019-08-22 20:06:04 +02002710 developer it reports everything available, which can include advanced
2711 information such as "breaking out of this loop" that are
2712 only relevant to a developer trying to understand a bug that
Willy Tarreau09fb0df2019-08-29 08:40:59 +02002713 only happens once in a while in field. Function names are
2714 only reported at this level.
Willy Tarreauf909c912019-08-22 20:06:04 +02002715
2716 It is highly recommended to always use the "user" level only and switch to
2717 other levels only if instructed to do so by a developer. Also it is a good
2718 idea to first configure the events before switching to higher levels, as it
2719 may save from dumping many lines if no filter is applied.
2720
2721trace <source> lock [criterion]
2722 Without argument, this will list all the criteria supported by this source
2723 for lock-on processing, and display the current choice by a star ('*') in
2724 front of it. Lock-on means that the source will focus on the first matching
2725 event and only stick to the criterion which triggered this event, and ignore
2726 all other ones until the trace stops. This allows for example to take a trace
2727 on a single connection or on a single stream. The following criteria are
2728 supported by some traces, though not necessarily all, since some of them
2729 might not be available to the source :
2730
2731 backend lock on the backend that started the trace
2732 connection lock on the connection that started the trace
2733 frontend lock on the frontend that started the trace
2734 listener lock on the listener that started the trace
2735 nothing do not lock on anything
2736 server lock on the server that started the trace
2737 session lock on the session that started the trace
2738 thread lock on the thread that started the trace
2739
2740 In addition to this, each source may provide up to 4 specific criteria such
2741 as internal states or connection IDs. For example in HTTP/2 it is possible
2742 to lock on the H2 stream and ignore other streams once a strace starts.
2743
2744 When a criterion is passed in argument, this one is used instead of the
2745 other ones and any existing tracking is immediately terminated so that it can
2746 restart with the new criterion. The special keyword "nothing" is supported by
2747 all sources to permanently disable tracking.
2748
2749trace <source> { pause | start | stop } [ [+|-|!]event]
2750 Without argument, this will list the events enabled to automatically pause,
2751 start, or stop a trace for this source. These events are specific to each
2752 trace source. With an argument, this will either enable the event for the
2753 specified action (if optionally prefixed by a '+') or disable it (if
2754 prefixed by a '-' or '!'). The special keyword "now" is not an event and
2755 requests to take the action immediately. The keywords "none" and "any" are
2756 supported just like in "trace event".
2757
2758 The 3 supported actions are respectively "pause", "start" and "stop". The
2759 "pause" action enumerates events which will cause a running trace to stop and
2760 wait for a new start event to restart it. The "start" action enumerates the
2761 events which switch the trace into the waiting mode until one of the start
2762 events appears. And the "stop" action enumerates the events which definitely
2763 stop the trace until it is manually enabled again. In practice it makes sense
2764 to manually start a trace using "start now" without caring about events, and
2765 to stop it using "stop now". In order to capture more subtle event sequences,
2766 setting "start" to a normal event (like receiving an HTTP request) and "stop"
2767 to a very rare event like emitting a certain error, will ensure that the last
2768 captured events will match the desired criteria. And the pause event is
2769 useful to detect the end of a sequence, disable the lock-on and wait for
2770 another opportunity to take a capture. In this case it can make sense to
2771 enable lock-on to spot only one specific criterion (e.g. a stream), and have
2772 "start" set to anything that starts this criterion (e.g. all events which
2773 create a stream), "stop" set to the expected anomaly, and "pause" to anything
2774 that ends that criterion (e.g. any end of stream event). In this case the
2775 trace log will contain complete sequences of perfectly clean series affecting
2776 a single object, until the last sequence containing everything from the
2777 beginning to the anomaly.
2778
2779trace <source> sink [<sink>]
2780 Without argument, this will list all event sinks available for this source,
2781 and the currently configured one will have a star ('*') prepended in front
2782 of it. Sink "none" is always available and means that all events are simply
2783 dropped, though their processing is not ignored (e.g. lock-on does occur).
2784 Other sinks are available depending on configuration and build options, but
2785 typically "stdout" and "stderr" will be usable in debug mode, and in-memory
2786 ring buffers should be available as well. When a name is specified, the sink
2787 instantly changes for the specified source. Events are not changed during a
2788 sink change. In the worst case some may be lost if an invalid sink is used
2789 (or "none"), but operations do continue to a different destination.
2790
Willy Tarreau370a6942019-08-29 08:24:16 +02002791trace <source> verbosity [<level>]
2792 Without argument, this will list all verbosity levels for this source, and the
2793 current one will be indicated by a star ('*') prepended in front of it. With
2794 an argument, this will change the verbosity level to the specified one.
2795
2796 Verbosity levels indicate how far the trace decoder should go to provide
2797 detailed information. It depends on the trace source, since some sources will
2798 not even provide a specific decoder. Level "quiet" is always available and
2799 disables any decoding. It can be useful when trying to figure what's
2800 happening before trying to understand the details, since it will have a very
2801 low impact on performance and trace size. When no verbosity levels are
2802 declared by a source, level "default" is available and will cause a decoder
2803 to be called when specified in the traces. It is an opportunistic decoding.
2804 When the source declares some verbosity levels, these ones are listed with
2805 a description of what they correspond to. In this case the trace decoder
2806 provided by the source will be as accurate as possible based on the
2807 information available at the trace point. The first level above "quiet" is
2808 set by default.
2809
Willy Tarreau2212e6a2015-10-13 14:40:55 +02002810
William Lallemand142db372018-12-11 18:56:45 +010028119.4. Master CLI
2812---------------
2813
2814The master CLI is a socket bound to the master process in master-worker mode.
2815This CLI gives access to the unix socket commands in every running or leaving
2816processes and allows a basic supervision of those processes.
2817
2818The master CLI is configurable only from the haproxy program arguments with
2819the -S option. This option also takes bind options separated by commas.
2820
2821Example:
2822
2823 # haproxy -W -S 127.0.0.1:1234 -f test1.cfg
2824 # haproxy -Ws -S /tmp/master-socket,uid,1000,gid,1000,mode,600 -f test1.cfg
William Lallemandb7ea1412018-12-13 09:05:47 +01002825 # haproxy -W -S /tmp/master-socket,level,user -f test1.cfg
William Lallemand142db372018-12-11 18:56:45 +01002826
2827The master CLI introduces a new 'show proc' command to surpervise the
2828processes:
2829
2830Example:
2831
2832 $ echo 'show proc' | socat /var/run/haproxy-master.sock -
William Lallemand1dc69632019-06-12 19:11:33 +02002833 #<PID> <type> <relative PID> <reloads> <uptime> <version>
2834 1162 master 0 5 0d00h02m07s 2.0-dev7-0124c9-7
William Lallemand142db372018-12-11 18:56:45 +01002835 # workers
William Lallemand1dc69632019-06-12 19:11:33 +02002836 1271 worker 1 0 0d00h00m00s 2.0-dev7-0124c9-7
2837 1272 worker 2 0 0d00h00m00s 2.0-dev7-0124c9-7
William Lallemand142db372018-12-11 18:56:45 +01002838 # old workers
William Lallemand1dc69632019-06-12 19:11:33 +02002839 1233 worker [was: 1] 3 0d00h00m43s 2.0-dev3-6019f6-289
William Lallemand142db372018-12-11 18:56:45 +01002840
2841
2842In this example, the master has been reloaded 5 times but one of the old
2843worker is still running and survived 3 reloads. You could access the CLI of
2844this worker to understand what's going on.
2845
Willy Tarreau52880f92018-12-15 13:30:03 +01002846When the prompt is enabled (via the "prompt" command), the context the CLI is
2847working on is displayed in the prompt. The master is identified by the "master"
2848string, and other processes are identified with their PID. In case the last
2849reload failed, the master prompt will be changed to "master[ReloadFailed]>" so
2850that it becomes visible that the process is still running on the previous
2851configuration and that the new configuration is not operational.
2852
William Lallemand142db372018-12-11 18:56:45 +01002853The master CLI uses a special prefix notation to access the multiple
2854processes. This notation is easily identifiable as it begins by a @.
2855
2856A @ prefix can be followed by a relative process number or by an exclamation
2857point and a PID. (e.g. @1 or @!1271). A @ alone could be use to specify the
2858master. Leaving processes are only accessible with the PID as relative process
2859number are only usable with the current processes.
2860
2861Examples:
2862
2863 $ socat /var/run/haproxy-master.sock readline
2864 prompt
2865 master> @1 show info; @2 show info
2866 [...]
2867 Process_num: 1
2868 Pid: 1271
2869 [...]
2870 Process_num: 2
2871 Pid: 1272
2872 [...]
2873 master>
2874
2875 $ echo '@!1271 show info; @!1272 show info' | socat /var/run/haproxy-master.sock -
2876 [...]
2877
2878A prefix could be use as a command, which will send every next commands to
2879the specified process.
2880
2881Examples:
2882
2883 $ socat /var/run/haproxy-master.sock readline
2884 prompt
2885 master> @1
2886 1271> show info
2887 [...]
2888 1271> show stat
2889 [...]
2890 1271> @
2891 master>
2892
2893 $ echo '@1; show info; show stat; @2; show info; show stat' | socat /var/run/haproxy-master.sock -
2894 [...]
2895
William Lallemanda57b7e32018-12-14 21:11:31 +01002896You can also reload the HAProxy master process with the "reload" command which
2897does the same as a `kill -USR2` on the master process, provided that the user
2898has at least "operator" or "admin" privileges.
2899
2900Example:
2901
2902 $ echo "reload" | socat /var/run/haproxy-master.sock
2903
2904Note that a reload will close the connection to the master CLI.
2905
William Lallemand142db372018-12-11 18:56:45 +01002906
Willy Tarreau2212e6a2015-10-13 14:40:55 +0200290710. Tricks for easier configuration management
2908----------------------------------------------
2909
2910It is very common that two HAProxy nodes constituting a cluster share exactly
2911the same configuration modulo a few addresses. Instead of having to maintain a
2912duplicate configuration for each node, which will inevitably diverge, it is
2913possible to include environment variables in the configuration. Thus multiple
2914configuration may share the exact same file with only a few different system
2915wide environment variables. This started in version 1.5 where only addresses
2916were allowed to include environment variables, and 1.6 goes further by
2917supporting environment variables everywhere. The syntax is the same as in the
2918UNIX shell, a variable starts with a dollar sign ('$'), followed by an opening
2919curly brace ('{'), then the variable name followed by the closing brace ('}').
2920Except for addresses, environment variables are only interpreted in arguments
2921surrounded with double quotes (this was necessary not to break existing setups
2922using regular expressions involving the dollar symbol).
2923
2924Environment variables also make it convenient to write configurations which are
2925expected to work on various sites where only the address changes. It can also
2926permit to remove passwords from some configs. Example below where the the file
2927"site1.env" file is sourced by the init script upon startup :
2928
2929 $ cat site1.env
2930 LISTEN=192.168.1.1
2931 CACHE_PFX=192.168.11
2932 SERVER_PFX=192.168.22
2933 LOGGER=192.168.33.1
2934 STATSLP=admin:pa$$w0rd
2935 ABUSERS=/etc/haproxy/abuse.lst
2936 TIMEOUT=10s
2937
2938 $ cat haproxy.cfg
2939 global
2940 log "${LOGGER}:514" local0
2941
2942 defaults
2943 mode http
2944 timeout client "${TIMEOUT}"
2945 timeout server "${TIMEOUT}"
2946 timeout connect 5s
2947
2948 frontend public
2949 bind "${LISTEN}:80"
2950 http-request reject if { src -f "${ABUSERS}" }
2951 stats uri /stats
2952 stats auth "${STATSLP}"
2953 use_backend cache if { path_end .jpg .css .ico }
2954 default_backend server
2955
2956 backend cache
2957 server cache1 "${CACHE_PFX}.1:18080" check
2958 server cache2 "${CACHE_PFX}.2:18080" check
2959
2960 backend server
2961 server cache1 "${SERVER_PFX}.1:8080" check
2962 server cache2 "${SERVER_PFX}.2:8080" check
2963
2964
296511. Well-known traps to avoid
2966-----------------------------
2967
2968Once in a while, someone reports that after a system reboot, the haproxy
2969service wasn't started, and that once they start it by hand it works. Most
2970often, these people are running a clustered IP address mechanism such as
2971keepalived, to assign the service IP address to the master node only, and while
2972it used to work when they used to bind haproxy to address 0.0.0.0, it stopped
2973working after they bound it to the virtual IP address. What happens here is
2974that when the service starts, the virtual IP address is not yet owned by the
2975local node, so when HAProxy wants to bind to it, the system rejects this
2976because it is not a local IP address. The fix doesn't consist in delaying the
2977haproxy service startup (since it wouldn't stand a restart), but instead to
2978properly configure the system to allow binding to non-local addresses. This is
2979easily done on Linux by setting the net.ipv4.ip_nonlocal_bind sysctl to 1. This
2980is also needed in order to transparently intercept the IP traffic that passes
2981through HAProxy for a specific target address.
2982
2983Multi-process configurations involving source port ranges may apparently seem
2984to work but they will cause some random failures under high loads because more
2985than one process may try to use the same source port to connect to the same
2986server, which is not possible. The system will report an error and a retry will
2987happen, picking another port. A high value in the "retries" parameter may hide
2988the effect to a certain extent but this also comes with increased CPU usage and
2989processing time. Logs will also report a certain number of retries. For this
2990reason, port ranges should be avoided in multi-process configurations.
2991
Dan Lloyd8e48b872016-07-01 21:01:18 -04002992Since HAProxy uses SO_REUSEPORT and supports having multiple independent
Willy Tarreau2212e6a2015-10-13 14:40:55 +02002993processes bound to the same IP:port, during troubleshooting it can happen that
2994an old process was not stopped before a new one was started. This provides
2995absurd test results which tend to indicate that any change to the configuration
2996is ignored. The reason is that in fact even the new process is restarted with a
2997new configuration, the old one also gets some incoming connections and
2998processes them, returning unexpected results. When in doubt, just stop the new
2999process and try again. If it still works, it very likely means that an old
3000process remains alive and has to be stopped. Linux's "netstat -lntp" is of good
3001help here.
3002
3003When adding entries to an ACL from the command line (eg: when blacklisting a
3004source address), it is important to keep in mind that these entries are not
3005synchronized to the file and that if someone reloads the configuration, these
3006updates will be lost. While this is often the desired effect (for blacklisting)
3007it may not necessarily match expectations when the change was made as a fix for
3008a problem. See the "add acl" action of the CLI interface.
3009
3010
301112. Debugging and performance issues
3012------------------------------------
3013
3014When HAProxy is started with the "-d" option, it will stay in the foreground
3015and will print one line per event, such as an incoming connection, the end of a
3016connection, and for each request or response header line seen. This debug
3017output is emitted before the contents are processed, so they don't consider the
3018local modifications. The main use is to show the request and response without
3019having to run a network sniffer. The output is less readable when multiple
3020connections are handled in parallel, though the "debug2ansi" and "debug2html"
3021scripts found in the examples/ directory definitely help here by coloring the
3022output.
3023
3024If a request or response is rejected because HAProxy finds it is malformed, the
3025best thing to do is to connect to the CLI and issue "show errors", which will
3026report the last captured faulty request and response for each frontend and
3027backend, with all the necessary information to indicate precisely the first
3028character of the input stream that was rejected. This is sometimes needed to
3029prove to customers or to developers that a bug is present in their code. In
3030this case it is often possible to relax the checks (but still keep the
3031captures) using "option accept-invalid-http-request" or its equivalent for
3032responses coming from the server "option accept-invalid-http-response". Please
3033see the configuration manual for more details.
3034
3035Example :
3036
3037 > show errors
3038 Total events captured on [13/Oct/2015:13:43:47.169] : 1
3039
3040 [13/Oct/2015:13:43:40.918] frontend HAProxyLocalStats (#2): invalid request
3041 backend <NONE> (#-1), server <NONE> (#-1), event #0
3042 src 127.0.0.1:51981, session #0, session flags 0x00000080
3043 HTTP msg state 26, msg flags 0x00000000, tx flags 0x00000000
3044 HTTP chunk len 0 bytes, HTTP body len 0 bytes
3045 buffer flags 0x00808002, out 0 bytes, total 31 bytes
3046 pending 31 bytes, wrapping at 8040, error at position 13:
3047
3048 00000 GET /invalid request HTTP/1.1\r\n
3049
3050
3051The output of "show info" on the CLI provides a number of useful information
3052regarding the maximum connection rate ever reached, maximum SSL key rate ever
3053reached, and in general all information which can help to explain temporary
3054issues regarding CPU or memory usage. Example :
3055
3056 > show info
3057 Name: HAProxy
3058 Version: 1.6-dev7-e32d18-17
3059 Release_date: 2015/10/12
3060 Nbproc: 1
3061 Process_num: 1
3062 Pid: 7949
3063 Uptime: 0d 0h02m39s
3064 Uptime_sec: 159
3065 Memmax_MB: 0
3066 Ulimit-n: 120032
3067 Maxsock: 120032
3068 Maxconn: 60000
3069 Hard_maxconn: 60000
3070 CurrConns: 0
3071 CumConns: 3
3072 CumReq: 3
3073 MaxSslConns: 0
3074 CurrSslConns: 0
3075 CumSslConns: 0
3076 Maxpipes: 0
3077 PipesUsed: 0
3078 PipesFree: 0
3079 ConnRate: 0
3080 ConnRateLimit: 0
3081 MaxConnRate: 1
3082 SessRate: 0
3083 SessRateLimit: 0
3084 MaxSessRate: 1
3085 SslRate: 0
3086 SslRateLimit: 0
3087 MaxSslRate: 0
3088 SslFrontendKeyRate: 0
3089 SslFrontendMaxKeyRate: 0
3090 SslFrontendSessionReuse_pct: 0
3091 SslBackendKeyRate: 0
3092 SslBackendMaxKeyRate: 0
3093 SslCacheLookups: 0
3094 SslCacheMisses: 0
3095 CompressBpsIn: 0
3096 CompressBpsOut: 0
3097 CompressBpsRateLim: 0
3098 ZlibMemUsage: 0
3099 MaxZlibMemUsage: 0
3100 Tasks: 5
3101 Run_queue: 1
3102 Idle_pct: 100
3103 node: wtap
3104 description:
3105
3106When an issue seems to randomly appear on a new version of HAProxy (eg: every
3107second request is aborted, occasional crash, etc), it is worth trying to enable
Dan Lloyd8e48b872016-07-01 21:01:18 -04003108memory poisoning so that each call to malloc() is immediately followed by the
Willy Tarreau2212e6a2015-10-13 14:40:55 +02003109filling of the memory area with a configurable byte. By default this byte is
31100x50 (ASCII for 'P'), but any other byte can be used, including zero (which
3111will have the same effect as a calloc() and which may make issues disappear).
Dan Lloyd8e48b872016-07-01 21:01:18 -04003112Memory poisoning is enabled on the command line using the "-dM" option. It
Willy Tarreau2212e6a2015-10-13 14:40:55 +02003113slightly hurts performance and is not recommended for use in production. If
Dan Lloyd8e48b872016-07-01 21:01:18 -04003114an issue happens all the time with it or never happens when poisoning uses
Willy Tarreau2212e6a2015-10-13 14:40:55 +02003115byte zero, it clearly means you've found a bug and you definitely need to
3116report it. Otherwise if there's no clear change, the problem it is not related.
3117
3118When debugging some latency issues, it is important to use both strace and
3119tcpdump on the local machine, and another tcpdump on the remote system. The
3120reason for this is that there are delays everywhere in the processing chain and
3121it is important to know which one is causing latency to know where to act. In
3122practice, the local tcpdump will indicate when the input data come in. Strace
3123will indicate when haproxy receives these data (using recv/recvfrom). Warning,
3124openssl uses read()/write() syscalls instead of recv()/send(). Strace will also
3125show when haproxy sends the data, and tcpdump will show when the system sends
3126these data to the interface. Then the external tcpdump will show when the data
3127sent are really received (since the local one only shows when the packets are
3128queued). The benefit of sniffing on the local system is that strace and tcpdump
3129will use the same reference clock. Strace should be used with "-tts200" to get
3130complete timestamps and report large enough chunks of data to read them.
3131Tcpdump should be used with "-nvvttSs0" to report full packets, real sequence
3132numbers and complete timestamps.
3133
3134In practice, received data are almost always immediately received by haproxy
3135(unless the machine has a saturated CPU or these data are invalid and not
3136delivered). If these data are received but not sent, it generally is because
3137the output buffer is saturated (ie: recipient doesn't consume the data fast
3138enough). This can be confirmed by seeing that the polling doesn't notify of
3139the ability to write on the output file descriptor for some time (it's often
3140easier to spot in the strace output when the data finally leave and then roll
3141back to see when the write event was notified). It generally matches an ACK
3142received from the recipient, and detected by tcpdump. Once the data are sent,
3143they may spend some time in the system doing nothing. Here again, the TCP
3144congestion window may be limited and not allow these data to leave, waiting for
3145an ACK to open the window. If the traffic is idle and the data take 40 ms or
3146200 ms to leave, it's a different issue (which is not an issue), it's the fact
3147that the Nagle algorithm prevents empty packets from leaving immediately, in
3148hope that they will be merged with subsequent data. HAProxy automatically
3149disables Nagle in pure TCP mode and in tunnels. However it definitely remains
3150enabled when forwarding an HTTP body (and this contributes to the performance
3151improvement there by reducing the number of packets). Some HTTP non-compliant
3152applications may be sensitive to the latency when delivering incomplete HTTP
3153response messages. In this case you will have to enable "option http-no-delay"
3154to disable Nagle in order to work around their design, keeping in mind that any
3155other proxy in the chain may similarly be impacted. If tcpdump reports that data
3156leave immediately but the other end doesn't see them quickly, it can mean there
Dan Lloyd8e48b872016-07-01 21:01:18 -04003157is a congested WAN link, a congested LAN with flow control enabled and
Willy Tarreau2212e6a2015-10-13 14:40:55 +02003158preventing the data from leaving, or more commonly that HAProxy is in fact
3159running in a virtual machine and that for whatever reason the hypervisor has
3160decided that the data didn't need to be sent immediately. In virtualized
3161environments, latency issues are almost always caused by the virtualization
3162layer, so in order to save time, it's worth first comparing tcpdump in the VM
3163and on the external components. Any difference has to be credited to the
3164hypervisor and its accompanying drivers.
3165
3166When some TCP SACK segments are seen in tcpdump traces (using -vv), it always
3167means that the side sending them has got the proof of a lost packet. While not
3168seeing them doesn't mean there are no losses, seeing them definitely means the
3169network is lossy. Losses are normal on a network, but at a rate where SACKs are
3170not noticeable at the naked eye. If they appear a lot in the traces, it is
3171worth investigating exactly what happens and where the packets are lost. HTTP
3172doesn't cope well with TCP losses, which introduce huge latencies.
3173
3174The "netstat -i" command will report statistics per interface. An interface
3175where the Rx-Ovr counter grows indicates that the system doesn't have enough
3176resources to receive all incoming packets and that they're lost before being
3177processed by the network driver. Rx-Drp indicates that some received packets
3178were lost in the network stack because the application doesn't process them
3179fast enough. This can happen during some attacks as well. Tx-Drp means that
3180the output queues were full and packets had to be dropped. When using TCP it
Dan Lloyd8e48b872016-07-01 21:01:18 -04003181should be very rare, but will possibly indicate a saturated outgoing link.
Willy Tarreau2212e6a2015-10-13 14:40:55 +02003182
3183
318413. Security considerations
3185---------------------------
3186
3187HAProxy is designed to run with very limited privileges. The standard way to
3188use it is to isolate it into a chroot jail and to drop its privileges to a
3189non-root user without any permissions inside this jail so that if any future
3190vulnerability were to be discovered, its compromise would not affect the rest
3191of the system.
3192
Dan Lloyd8e48b872016-07-01 21:01:18 -04003193In order to perform a chroot, it first needs to be started as a root user. It is
Willy Tarreau2212e6a2015-10-13 14:40:55 +02003194pointless to build hand-made chroots to start the process there, these ones are
3195painful to build, are never properly maintained and always contain way more
3196bugs than the main file-system. And in case of compromise, the intruder can use
3197the purposely built file-system. Unfortunately many administrators confuse
3198"start as root" and "run as root", resulting in the uid change to be done prior
3199to starting haproxy, and reducing the effective security restrictions.
3200
3201HAProxy will need to be started as root in order to :
3202 - adjust the file descriptor limits
3203 - bind to privileged port numbers
3204 - bind to a specific network interface
3205 - transparently listen to a foreign address
3206 - isolate itself inside the chroot jail
3207 - drop to another non-privileged UID
3208
3209HAProxy may require to be run as root in order to :
3210 - bind to an interface for outgoing connections
3211 - bind to privileged source ports for outgoing connections
Dan Lloyd8e48b872016-07-01 21:01:18 -04003212 - transparently bind to a foreign address for outgoing connections
Willy Tarreau2212e6a2015-10-13 14:40:55 +02003213
3214Most users will never need the "run as root" case. But the "start as root"
3215covers most usages.
3216
3217A safe configuration will have :
3218
3219 - a chroot statement pointing to an empty location without any access
3220 permissions. This can be prepared this way on the UNIX command line :
3221
3222 # mkdir /var/empty && chmod 0 /var/empty || echo "Failed"
3223
3224 and referenced like this in the HAProxy configuration's global section :
3225
3226 chroot /var/empty
3227
3228 - both a uid/user and gid/group statements in the global section :
3229
3230 user haproxy
3231 group haproxy
3232
3233 - a stats socket whose mode, uid and gid are set to match the user and/or
3234 group allowed to access the CLI so that nobody may access it :
3235
3236 stats socket /var/run/haproxy.stat uid hatop gid hatop mode 600
3237