[systemd-devel] Antw: Re: Unexplainable unit restart ("Start request repeated too quickly")

[Michael Chapman]

On Mon, 3 Jun 2019, Ulrich Windl wrote:
[...]
> Hi!
> 
> The generator unit is:
> [Unit]
> Description=I/O performance monitor instance generator
> Documentation=man:iotwatch-generator(8) man:iotwatch at .service(8)
> Wants=nss-user-lookup.target time-sync.target paths.target
> After=nss-user-lookup.target time-sync.target paths.target
> ConditionPathExists=/etc/iotwatch.conf
> Conflicts=shutdown.target
> 
> [Service]
> Type=oneshot
> ExecStart=/usr/lib/iotwatch/iotwatch-generator /run/systemd/system
> TimeoutStartSec=10
> RestartPreventExitStatus=2 3 4 5
> StartLimitBurst=1
> 
> [Install]
> WantedBy=default.target iotwatch.target

That looks fine, though it _might_ make sense for it to have 
RemainAfterExit= turned on. After all, if default.target or 
iotwatch.target get restarted for any reason, then this unit will be 
started again.

It's very weird to have what appears to be a generator done as a service 
though. Any idea why that might be the case?

> The iotwatch.target is:
> [Unit]
> Description=iotwatch I/O performance monitor
> Documentation=man:iotwatch at .service(8) man:iotwatch-generator(8)
> After=nss-lookup.target time-sync.target paths.target
> Wants=iotwatch at NFS1.service iotwatch at NFS2.service iotwatch at LOC1.service 
> 
> [Install]
> WantedBy=default.target
> 
> and the instance services look like:
> # automatically generated by /usr/lib/iotwatch/iotwatch-generator
> 
> [Unit]
> Description=iotwatch I/O performance monitor instance "LOC1"
> Documentation=man:iotwatch(1) man:iotwatch at .service(8)
> SourcePath=/etc/iotwatch.conf
> PartOf=iotwatch.target

That also seems to imply that starting and stopping iotwatch.target would 
be something that happens with some regularity.

> Requires=iotwatch-generator.service
> Wants=nss-user-lookup.target time-sync.target paths.target
> After=iotwatch-generator.service
> After=nss-user-lookup.target time-sync.target paths.target
> ConditionPathExists=/etc/passwd
> Conflicts=shutdown.target
> 
> [Service]
> Type=forking
> RuntimeDirectory=iotwatch-LOC1
> WorkingDirectory=/var/run/iotwatch-LOC1
> ExecStartPre=/bin/sh -c '...'
> ExecStart=@/var/run/iotwatch-LOC1/iotwatch-LOC1 iotwatch-LOC1 -l ...
> /etc/passwd
> ExecStartPost=/usr/bin/sleep 0.2
> TimeoutStartSec=10
> ExecStop=/var/run/iotwatch-LOC1/iotwatch-LOC1 -l ...
> #SyslogIdentifier=%p-LOC1
> TimeoutStopSec=30
> PIDFile=/var/run/iotwatch-LOC1/iotwatch-LOC1.pid
> Restart=always
> RestartSec=10s
> RestartPreventExitStatus=1
> StartLimitBurst=1
> 
> [Install]
> WantedBy=iotwatch.target
> 
> > 
> > It might also be good to know the RequiredBy, WantedBy, TriggeredBy, 
> > RequisiteOf and PartOf properties of this iotwatch-generator.service (see 
> > `systemctl show iotwatch-generator.service`), since they're possible ways 
> > in which the service may be implicitly started or restarted.
> 
> Yes, but I'm missing a log message that explains what happened.

Sure, there isn't one. That's why I'm asking about the properties.