Re: 3.18.1: duplicate cf-exexd processes

On Tue, 2022-03-15 at 13:25 +0100, Marco Marongiu wrote:
> 
> But...
> 
> As you know, systemd is a bit bossy and likes to have everything under its control. This
> unexpected process that pops up and later disappears upsets it a tiny bit, but enough that it
> feels compelled to spew log messages all around about this process that, according to its opinion,
> should not be there.
> 
> But it may not be just about spewing log messages. In fact, I am not sure that systemd is just
> content of "observing" that there is a process that should not be there. If you look at the logs I
> posted, you will see that systemd forces a restart of cf-execd, probably to try and rectify a
> situation that doesn't match systemd's own desired state. On my laptop, cf-execd was restarted
> tens of times in a few hours. Although harmless (or is it?), that's not a desirable behaviour.
> 
> I would suggest that this change also requires some tweaks in the systemd unit files, what do you
> think?
I tried installing and bootstrapping a Debian 11 host with CFEngine 3.18.1 (Enterprise) and I don't
see any problem:

root@ip-172-31-23-195:~# systemctl status cf-execd
● cf-execd.service - CFEngine Execution Scheduler
     Loaded: loaded (/lib/systemd/system/cf-execd.service; enabled; vendor preset: enabled)
     Active: active (running) since Tue 2022-03-15 17:42:53 UTC; 26min ago
   Main PID: 931 (cf-execd)
      Tasks: 1 (limit: 17979)
     Memory: 6.6M
        CPU: 7.314s
     CGroup: /system.slice/cf-execd.service
             └─931 /var/cfengine/bin/cf-execd --no-fork

Mar 15 17:42:53 ip-172-31-23-195 systemd[1]: Started CFEngine Execution Scheduler.

root@ip-172-31-23-195:~# journalctl -u cf-execd.service
-- Journal begins at Tue 2022-03-15 17:38:48 UTC, ends at Tue 2022-03-15 18:08:53 UTC. --
Mar 15 17:42:53 ip-172-31-23-195 systemd[1]: Started CFEngine Execution Scheduler.

systemd is actually fine with daemons forking and reaping their child processes. The
cf-execd.service says:

[Service]
Type=simple
ExecStart=/var/cfengine/bin/cf-execd --no-fork
Restart=always
RestartSec=10
KillMode=process

so systemd knows it should care about the /var/cfengine/bin/cf-execd process itself and cf-execd is
told to NOT fork when it starts (i.e. to run in foreground).

What I've seen in your logs was that something else was force-killing cf-execd and then systemd
complained there was a child process left over. That's because cf-execd was force-killed and could
not reap its child process. My bet would be that it was cf-agent killing the cf-execd process
because it was running with a policy saying that there should only be a single cf-execd process
running. With 3.18.1 MPF policy, cf-agent runs expect 1 or 2 cf-execd processes, systemd expects the
main process to be running (and forking) and the service is just running fine (as can be seen
above).

--
Vratislav

-- 
You received this message because you are subscribed to the Google Groups "help-cfengine" group.
To unsubscribe from this group and stop receiving emails from it, send an email to [email protected].
To view this discussion on the web visit https://groups.google.com/d/msgid/help-cfengine/7db40191432f71e2ea58b9e77f6717aa7b6d6fa4.camel%40northern.tech.