How can I configure a systemd service to restart periodically?

Question

I have a simple systemd service that needs to be periodically restarted to keep its process from bugging out. Is there a configuration option for systemd services to periodically restart them? All of the Restart* options seem to pertain to restarting the service when it exits.

Answer 1

For systemd version >= 229, there is an option called RuntimeMaxSec, which terminates the service after it has been running for the given period of time.

e.g.

[Service] Restart=always RuntimeMaxSec=604800 

To me this seems more elegant than abusing Type=notify and WatchdogSec.

systemd provides a clean way to add and override directives in systemd unit files provided by vendors. Drop-In Units are described in man systemd.unit. For example, if you wanted to periodically restart the foo service provided by a package, you would create a file named /etc/systemd/system/foo.service.d/periodic-restart.conf. The contents would be as shown above. Then:

 systemctl daemon-reload  systemctl restart foo 

You can confirm that the Drop-In unit has been loaded because it will be reported in the status output:

 systemctl status 

Finally, you can confirm the directive has been included by searching the systemctl show output:

 systemctl show foo.service | grep RuntimeMax 

The directive reported by systemctl show will be "RuntimeMaxUSec`

Answer 2

I saw a solution here that seemed elegant, if a bit roundabout. The key idea is to create a one-shot service triggered by a timer that restarts another service.

For the timer:

[Unit] Description=Do something daily  [Timer] OnCalendar=daily Persistent=true  [Install] WantedBy=timers.target 

For the one-shot service:

[Unit] Description=Restart service  [Service] Type=oneshot ExecStart=/usr/bin/systemctl try-restart my_program.service 

For the one-shot service on Ubuntu 16.04 LTS:

[Unit] Description=Restart service  [Service] Type=oneshot ExecStart=/bin/systemctl try-restart my_program.service 

This solution lets you leverage systemd's timers, including the ability to restart the service at a particular time of day, and not just after some amount of time has elapsed.