activate and run oneshot service before deactivation of another service

Question

I have a oneshot-type service that I would like to run prior to the deactivation of another service. In other words, any time the other service receives a signal to deactivate, I want my service to activate, run its process, and terminate. Only when my service is complete would the other service be allowed to deactivate.

How do I achieve this in systemd?

Answer 1

well there is one possible way, use OnFailure=xyz.service in [Unit] section of your service file which is deactivating, where xyz.service will be the service which you want to activate.

Now there is one cache, if you want to terminate the newly activated service after running you process and keep the process running, you will have to run that service using shell script and run that script through ExecStart=/bin/sh lmn.sh in your xyz.service file.

Else you can directly give ExecStart=/usr/bin/hello to run your process. Here your service file will be in active state till your process runs.

eg. the service file which is deactivating.

[Unit]
Description=...
OnFailure=xyz.service

[Service]
.
.
.

xyz.service file

[Unit]
.
.

[Service]
.
.
ExecStart=/bin/sh lmn.sh
.
.

or

ExecStart=/usr/bin/hello