Add graceful shutdown to systemd unit

[bharrisau]

It's a bit hacky to get around the lack of asynchronous stop commands. But I've got something like this to give a 5 minute window to the process to finish any remaining work.

[Service]
ExecStart=/home/fishnet/fishnet --auto-update --conf /home/fishnet/fishnet.ini run
ExecStop=/bin/kill -INT "$MAINPID"
ExecStop=/usr/bin/sh -c 'while kill -0 "$MAINPID" 2>/dev/null; do sleep 1; done'
KillMode=mixed
TimeoutStopSec=300

[niklasf]

Generally such long timeouts for shutdown are not acceptable, so instead the default KillSignal=SIGTERM is used. This will cause a somewhat graceful shutdown, i.e., work won't be completed, but the server is notified.

The hack above can be simplified to:

KillMode=mixed
KillSignal=SIGINT
TimeoutStopSec=300

[bharrisau]

You don't get the SIGTERM then though, just straight to SIGKILL if the batch takes too long. That might be worse as the server isn't notified or anything.

Yes, the 5 minute time isn't for everyone. Just shared it incase it was handy.

On Thu, 22 Feb 2024, at 2:42 AM, Niklas Fiekas wrote:

Generally such long timeouts for shutdown are not acceptable, so instead the default KillSignal=SIGTERM is used. This will cause a somewhat graceful shutdown, i.e., work won't be completed, but the server is notified.

The hack above can be simplified to:

KillMode=mixed KillSignal=SIGINT TimeoutStopSec=300

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[niklasf]

Ah, interesting. I didn't realize how nicely your snippet works: So it's immediate SIGINT, SIGTERM after the timeout, and then eventually SIGKILL if something went wrong?

[bharrisau]

Yeah. But there is only 1 timeout value, so it's the same between SIGINT to SIGTERM, and SIGTERM to SIGKILL.

On Fri, 23 Feb 2024, at 6:08 PM, Niklas Fiekas wrote:

Ah, interesting. I didn't realize how nicely your snippet works: So it's immediate SIGINT, SIGTERM after the timeout, and then eventually SIGKILL if something went wrong?

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