Hi HAproxy community,
In our HAproxy deployment, access to runtime API is extremely critical, it
is used for:-
- collecting metrics
- managing servers in a backend (SoT is not DNS, so we have to use runtime
API), etc
I observed that, when soft-stop is in progress, we get the following error
while performing a connect.
connect(5, {sa_family=AF_UNIX, sun_path="path/to/haproxy.sock"}, 60) = -1
ECONNREFUSED (Connection refused)
recvfrom(3, 0x7ffcc675fe10, 519, MSG_DONTWAIT, NULL, NULL) = -1 EAGAIN
(Resource temporarily unavailable)
Due to this, we're unable to perform any operations or collect metrics
while haproxy is in soft stop, for us, that's a long time as we use the
current settings.
close-spread-time 10m
hard-stop-after 11m
"stats socket" (unix socket) is configured on one of the production
frontends, we're using version "version 2.8.0-01b97d-15 2023/09/26".
Will it make sense if HAproxy had an option to not disable runtime API
during soft-stop, perhaps an argument
While exploring the code, I noticed that the soft-stop code stops all
"stoppable
listeners"
<https://sourcegraph.com/github.com/haproxy/haproxy/-/blob/src/proxy.c?L2280>,
I wonder if there's a way to make a listener non-stoppable?
Are there any workarounds to getting around this limitation, while also
retaining the soft-stop behavior?
Our reason to use soft-stop is to do best-effort into gracefully draining
client connections (send Connection: close). We also don't have a way to
drain H2 connections proactively, but that's a discussion for another day.
Cheers,
Abhijeet (https://abhi.host)
