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I have a problem where on rare occasions my Type=simple systemd service hangs or gets caught in a loop. This causes its timer to stop scheduling the service because, as confirmed with sudo systemctl status myservice, the service is still running when it should have long exited. I haven't yet figured out the bug but it isn't critical. But in the mean time I don't want it to stop scheduling future runs.

Is there a way to specify in the systemd service file a maximum run time, after which it will force stop?

[Unit]
Description=scripts should run and exit but occasionally hangs or infinite loop      

[Service]
SyslogIdentifier=myservice
Environment='MYVAR=myvar'
User=deanresin
Type=simple
ExecStart=/usr/bin/python3 /home/deanresin/myscript
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  • 2
    A service that runs and exits should be of type oneshot, not simple Commented Aug 16, 2023 at 5:54
  • Thanks! I was always confused between Type simple and oneshot even after reading the documentation. Commented Aug 16, 2023 at 18:57

2 Answers 2

Reset to default
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TimeoutStartSec should be used. As @muru mentioned in the comment, the correct way to run a script that should exit is to use Type=oneshot instead of Type=simple.

For example, if your script is normally executed in under 10 seconds, your config would be:

[Service]
Type=oneshot
TimeoutStartSec=10
SyslogIdentifier=myservice
Environment='MYVAR=myvar'
User=deanresin
ExecStart=/usr/bin/python3 /home/deanresin/myscript

If the script takes more than 10 seconds to execute, it will be killed, and the service would show as failed.

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  • I think you need to remove the "s" from TimeoutStartSec=10s. Commented Aug 16, 2023 at 19:10
  • According to the documentation, either 10 or 10s would work equally well, but I removed the trailing s from the command as it's not needed. Commented Aug 17, 2023 at 6:48
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    I think it was a little ambiguous. It said for long time 5m12s it takes units but for only seconds it is unit-less. But that isn't really clear that it won't work with a unit and it wouldn't make sense for it to not work. Such a strange design decision and poor documentation. Commented Aug 17, 2023 at 18:47
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Since systemd 229 (2016-02-11), the RuntimeMaxSec option can be used. This does not require (or even work with) Type=oneshot as it sets a time limit for the "active" state instead of "activating".

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