BUG/MINOR: init: make the automatic maxconn consider the max of soft/hard limits
James Stroehmann reported something working as documented but that can
be considered as a regression in the way the automatic maxconn is
calculated from the process' limits :
https://www.mail-archive.com/haproxy@formilux.org/msg36523.html
The purpose of the changes in 2.0 was to have maxconn default to the
highest possible value permitted to the user based on the ulimit -n
setting, however the calculation starts from the soft limit, which
can be lower than what users were allowed to with previous versions
where the default value of 2000 would force a higher ulimit -n as
long as it fitted in the hard limit.
Usually this is not noticeable if the user changes the limits, because
quite commonly setting a new value restricts both the soft and hard
values.
Let's instead always use the max between the hard and soft limits, as
we know these values are permitted. This was tried on the following
setup:
$ cat ulimit-n.cfg
global
stats socket /tmp/sock1 level admin
$ ulimit -n
1024
Before the change the limits would show like this:
$ socat - /tmp/sock1 <<< "show info" | grep -im2 ^Max
Maxsock: 1023
Maxconn: 489
After the change the limits are now much better and more in line with
the default settings in earlier versions:
$ socat - /tmp/sock1 <<< "show info" | grep -im2 ^Max
Maxsock: 4095
Maxconn: 2025
The difference becomes even more obvious when running moderately large
configs with hundreds of checked servers and hundreds of listeners:
$ cat ulimit-n.cfg
global
stats socket /tmp/sock1 level admin
listen l
bind :10000-10300
server-template srv- 300 0.0.0.0 check disabled
Before After
Maxsock 1024 4096
Maxconn 189 1725
This issue is tagged as minor since a trivial config change fixes it,
but it would help new users to have it backported as far as 2.0.
(cherry picked from commit b1beaa302c4c35080f217ce5fb63fed4530e1879)
Signed-off-by: Willy Tarreau <w@1wt.eu>
(cherry picked from commit 3083a3289573da1d76b856d5018325b1d6cf852d)
Signed-off-by: Willy Tarreau <w@1wt.eu>
diff --git a/src/haproxy.c b/src/haproxy.c
index 138b54e..870dfd1 100644
--- a/src/haproxy.c
+++ b/src/haproxy.c
@@ -1382,7 +1382,7 @@
int ssl_sides = !!global.ssl_used_frontend + !!global.ssl_used_backend;
int engine_fds = global.ssl_used_async_engines * ssl_sides;
int pipes = compute_ideal_maxpipes();
- int remain = rlim_fd_cur_at_boot;
+ int remain = MAX(rlim_fd_cur_at_boot, rlim_fd_max_at_boot);
int maxconn;
/* we have to take into account these elements :