[systemd-devel] Systemd hang when restarting a service during shutdown

[Sean Nyekjaer]

On Mon, Nov 08, 2021 at 03:47:36PM +0200, Uoti Urpala wrote:
> On Mon, 2021-11-08 at 12:05 +0100, Sean Nyekjaer wrote:
> > Regarding,
> > https://github.com/systemd/systemd/issues/21203
> > 
> > I think the point of the issue missed when the issue got closed.
> > 
> > We have a service that is changing configs for systemd-networkd and
> > issuing a `systemctl restart systemd-networkd`.
> > An other service is checking uptime and issues a `systemctl reboot`,
> > when our max uptime have been exeeced.
> > If restart of systemd-networkd happens while a reboot is in progress,
> > the system will hang "forever" (and continue to pet the watchdog).
> 
> The issue shows you using "systemctl start systemd-reboot". That is not
> the right way to reboot. Use "systemctl reboot" instead. I suspect this
> is related to why the reboot may stop partway: your command does not
> start the reboot tasks in "irreversible" mode, which means that any
> following contrary command, such as explicitly (re)starting a unit that
> was going to be shut down, is going to implicitly cancel the
> conflicting reboot action.
> 
> You should also be using "try-restart" instead of "restart". If your
> intent is to change configs, you want to say "make sure old configs are
> not in use" rather than "enforce that the service is running now". (I
> think making the "restart" command have "start" semantics was a design
> mistake, and the "try-restart"/"restart" pair would have been better
> named "restart"/"start-or-restart".)

I can reproduce it with "systemctl reboot"...

I'll try the "try-restart" option, and report back

Thanks

/Sean