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*From:* Tim Düsterhus [mailto:t...@bastelstu.be]
*Sent:* Friday, April 26, 2019, 15:03 EDT
*To:* Patrick Hemmer <hapr...@stormcloud9.net>, William Lallemand
<wlallem...@haproxy.com>
*Cc:* haproxy@formilux.org, w...@1wt.eu
*Subject:* [PATCH] MINOR: systemd: Make use of master socket in systemd unit
Patrick,
Am 26.04.19 um 20:55 schrieb Patrick Hemmer:
One other consideration is a problem I've been looking to address, and
that's better reloads. Right now the systemd unit sends a signal for the
reload, but sending a signal gets no feedback on whether the reload
operation was successful or not.
Have you checked that you are using Type=notify in your unit file? It
uses systemd's sd_notify API to communicate the reload to systemd which
should do what you are searching for.
See this mailing list thread:
https://www.mail-archive.com/haproxy@formilux.org/msg27874.html
Best regards
Tim Düsterhus
Yes, we use Type=notify. The problem though is that systemd is reporting
reload success even if the reload fails.
Take the following example config:
global
stats socket /tmp/foo
With the current systemd file provided by haproxy, I copied it as
"haproxy-test.service" and modified one line to the following:
Environment="CONFIG=/tmp/haproxy.cfg" "PIDFILE=/run/haproxy-test.pid"
And started haproxy:
# systemctl start haproxy-test.service
-- Logs begin at Thu 2019-04-11 15:13:39 EDT. --
Apr 29 14:24:14 fll2albs01qa2 systemd[1]: Starting HAProxy Load Balancer...
Apr 29 14:24:14 fll2albs01qa2 haproxy[27702]: [NOTICE] 118/142414
(27702) : New worker #1 (27704) forked
Apr 29 14:24:14 fll2albs01qa2 systemd[1]: Started HAProxy Load Balancer.
I then edited the config and changed the stats socket line to:
stats socket /notmp/foo
And then tried a reload:
# systemctl reload haproxy-test.service
-- Logs begin at Thu 2019-04-11 15:13:39 EDT. --
Apr 29 14:24:47 fll2albs01qa2 haproxy[27702]: [WARNING] 118/142447
(27702) : Reexecuting Master process
Apr 29 14:24:47 fll2albs01qa2 haproxy[27702]: [ALERT] 118/142447 (27702)
: Starting frontend GLOBAL: cannot bind UNIX socket [/notmp/foo]
Apr 29 14:24:47 fll2albs01qa2 haproxy[27702]: [WARNING] 118/142447
(27702) : Reexecuting Master process in waitpid mode
Apr 29 14:24:47 fll2albs01qa2 haproxy[27702]: [WARNING] 118/142447
(27702) : Reexecuting Master process
Apr 29 14:24:47 fll2albs01qa2 systemd[1]: Reloaded HAProxy Load Balancer.
# systemctl status haproxy-test.service
● haproxy-test.service - HAProxy Load Balancer
Loaded: loaded (/etc/systemd/system/haproxy-test.service; disabled;
vendor preset: disabled)
Active: active (running) since Mon 2019-04-29 14:24:14 EDT; 45s ago
Process: 28335 ExecReload=/bin/kill -USR2 $MAINPID (code=exited,
status=0/SUCCESS)
Process: 28334 ExecReload=/usr/sbin/haproxy -f $CONFIG -c -q
(code=exited, status=0/SUCCESS)
Process: 27700 ExecStartPre=/usr/sbin/haproxy -f $CONFIG -c -q
(code=exited, status=0/SUCCESS)
Main PID: 27702 (haproxy)
Memory: 2.9M
CGroup: /system.slice/haproxy-test.service
├─27702 /usr/sbin/haproxy -Ws -f /tmp/haproxy.cfg -p
/run/haproxy-test.pid -sf 27704
└─27704 /usr/sbin/haproxy -Ws -f /tmp/haproxy.cfg -p
/run/haproxy-test.pid
Note that the reload failed, but systemd reports success.
With older versions of haproxy (<1.8) we had a script which checked the
PID of the master process and that it changed after sending SIGUSR2.
This strategy no longer works.
