Restrict restarting systemd service with timer assigned

Question

I have a systemd service unit with OnCalendar timer assigned to it. That service invokes JVM, which runs code, that has to be started only on a specific schedule.

This systemd unit (and several others) are managed by the ansible playbook, which uses openstack/ansible-role-systemd_service role. It restarts systemd services every time I make some changes in their unit files.

Also, there's a handler, which restarts all the services every time Gitlab CI pipeline runs this ansible playbook and uploads a new .jar artifact to a server.

Is there any systemd built-in mechanism to restrict restarting service with timer assigned to it? Still, I have to be able to stop/start those services manually when it's needed.

Seems like I can fork that ansible role and add some check, but I wonder for some native and more straight-forward way to achieve this.

Answer 1

Seems I've found the way:

Create and don't enable .service unit, that would contain next:

[Unit]
After = network-online.target
...

[Service]
Type = simple
...
SuccessExitStatus = 143
RestartForceExitStatus = 143
Restart = on-failure
RemainAfterExit = False
StandardOutput = null
StandardError = syslog

[̶I̶n̶s̶t̶a̶l̶l̶]
W̶a̶n̶t̶e̶d̶B̶y̶ ̶=̶ ̶m̶u̶l̶t̶i̶-̶u̶s̶e̶r̶.̶t̶a̶r̶g̶e̶t̶

Create and enable .timer unit, that would contain next:

[Timer]
O̶n̶B̶o̶o̶t̶S̶e̶c̶ ̶=̶ ̶0̶m̶i̶n̶
OnCalendar = *-*-* 18:00:00
Persistent = yes

[Install]
WantedBy=multi-user.target

A little explanation:

After = network-online.target

Needed to make sure that service would start only after getting online.

Restart = on-failure
SuccessExitStatus = 143
RestartForceExitStatus = 143

Needed to be able to kill the main process and make systemd restart the service, or stop the service w/o systemd marking it failed . It's because JVM returning 143 exit code when the main process receives SIGTERM and stops gracefully.

RemainAfterExit = False  

Needed for .timer to understand that .service stoped. Either way, .timer would hang in the running state, and won't run service next time.

StandardOutput = null
StandardError = syslog

Needed to stop the main process from writing its INFO log to syslog, and write there only ERRORs.

[̶I̶n̶s̶t̶a̶l̶l̶]
W̶a̶n̶t̶e̶d̶B̶y̶ ̶=̶ ̶m̶u̶l̶t̶i̶-̶u̶s̶e̶r̶.̶t̶a̶r̶g̶e̶t̶

Omitted cause the service has to be disabled. Either way, it would be stared on system boot.

Persistent = yes

Needed to be able to start service later that day after system boot, if the target time was missed.

O̶n̶B̶o̶o̶t̶S̶e̶c̶ ̶=̶ ̶0̶m̶i̶n̶

Omitted cause OnCalendar was used.

All those changes seem to have done the trick.