mirrors/haproxy
1
0
Fork 0
mirror of https://git.haproxy.org/git/haproxy.git/ synced 2025-09-21 22:01:31 +02:00
Code Issues Projects Releases Wiki Activity

BUG/MEDIUM: resolvers: Force the connect timeout for DNS resolutions

Browse Source 
Timeouts for dynamic resolutions are not handled at the stream level but by
the resolvers themself. It means there is no connect, client and server
timeouts defined on the internal proxy used by a resolver.

While it is not an issue for DNS resolution over UDP, it can be a problem
for resolution over TCP. New sessions are automatically created when
required, and killed on excess. But only established connections are
considered. Connecting ones are never killed. Because there is no conncet
timeout, we rely on the kernel to report a connection error. And this may be
quite long.

Because resolutions are periodically triggered, this may lead to an excess
of unusable sessions in connecting state. This also prevents HAProxy to
quickly exit on soft-stop. It is annoying, especially because there is no
reason to not set a connect timeout.

So to mitigate the issue, we now use the "resolve" timeout as connect
timeout for the internal proxy attached to a resolver.

This patch should be backported as far as 2.4.
This commit is contained in:
Christopher Faulet 2023-04-11 08:04:04 +02:00
parent 142cc1b52a
commit 5220a8c5c4
1 changed files with 5 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

7
src/resolvers.c
View File

@ -3245,7 +3245,7 @@ void resolvers_setup_proxy(struct proxy *px)
px->conn_retries = 1;
px->timeout.server = TICK_ETERNITY;
px->timeout.client = TICK_ETERNITY;
px->timeout.connect = TICK_ETERNITY;
px->timeout.connect = 1000; // by default same than timeout.resolve
px->accept = NULL;
px->options2 |= PR_O2_INDEPSTR | PR_O2_SMARTCON;
}
@ -3714,8 +3714,11 @@ int cfg_parse_resolvers(const char *file, int linenum, char **args, int kwm)
}
if (args[1][2] == 't')
curr_resolvers->timeout.retry = tout;
else
else {
curr_resolvers->timeout.resolve = tout;
curr_resolvers->px->timeout.connect = tout;
}
}
else {
ha_alert("parsing [%s:%d] : '%s' expects 'retry' or 'resolve' and <time> as arguments got '%s'.\n",