How to restart service after some time

systemd

We have multiple systems that suffer from a firmware bug. The vendor is aware of the problem and will fix the firmware bug. Until then we have to live with a workaround: restart the relevant service some time after bootup.

There are mechanisms in systemd to control the restart of a failed service but they are not of help here because the service starts successfully. Just delaying the start of the service by – say – 1 minute does not help, it needs to be started twice.

So what's the best way to automatically restart a service after the system is up?

Best Answer

Create a .timer unit to control the .service unit.

Use the same base name as the service, so if the service were called thing, in /etc/systemd/system/foo.timer

[Unit]
Description=Start broken thing twice

[Timer]
OnBootSec=1min
OnBootSec=2min

[Install]
WantedBy=timers.target

Then enable this new timer. systemctl enable thing.timer

As the service remains active even if it has this problem, edit overrides such that it doesn't. systemctl edit thing.service
Which to change is hard to say without seeing the original unit. Perhaps add a ExecStartPost= command that returns 0 only if the device is in a good state. Or change RemainAfterExit=no to force a oneshot to not stay active.

Related Solutions

Systemd – How to Set Environment Variable in Service

Times change and so do best practices.

The current best way to do this is to run systemctl edit myservice, which will create an override file for you or let you edit an existing one.

In normal installations this will create a directory /etc/systemd/system/myservice.service.d, and inside that directory create a file whose name ends in .conf (typically, override.conf), and in this file you can add to or override any part of the unit shipped by the distribution.

For instance, in a file /etc/systemd/system/myservice.service.d/myenv.conf:

[Service]
Environment="SECRET=pGNqduRFkB4K9C2vijOmUDa2kPtUhArN"
Environment="ANOTHER_SECRET=JP8YLOc2bsNlrGuD6LVTq7L36obpjzxd"

Also note that if the directory exists and is empty, your service will be disabled! If you don't intend to put something in the directory, ensure that it does not exist.

For reference, the old way was:

The recommended way to do this is to create a file /etc/sysconfig/myservice which contains your variables, and then load them with EnvironmentFile.

For complete details, see Fedora's documentation on how to write a systemd script.

Convert an fstab entry to a systemd mount unit on CoreOS

defaults is redundant. When any other options are in use, it can be omitted. It only exists to fill the relevant column in fstab.

And since auto is already a default, it too is redundant.

Best Answer

Related Solutions

Systemd – How to Set Environment Variable in Service

Convert an fstab entry to a systemd mount unit on CoreOS

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