Systemd with multiple execStart [closed]

Question

Is it possible to create service with the same script started with different input parameters?

Example:

[Unit]
Description=script description

[Service]
Type=simple
ExecStart=/script.py parameters1
ExecStart=/script.py parameters2
Restart=on-failure

[Install]
WantedBy=multi-user.target

Is it possible?

Will it be launched in serial-mode? Or in two different process?

Answer 1

if Type=simple in your unit file, you can only specify one ExecStart, but you can add as many ExecStartPre, ExecStartPost, but none of this is suited for long running commands, because they are executed serially and everything one start is killed before starting the next one.

If Type=oneshot you can specify multiple ExecStart, they run serially not in parallel.

If what you want is to run multiple units in parallel, there a few things you can do:

If they differ on 1 param

You can use template units, so you create a /etc/systemd/system/[email protected]. NOTE: (the @ is important).

[Unit] Description=script description %I  [Service] Type=simple ExecStart=/script.py %i Restart=on-failure  [Install] WantedBy=multi-user.target 

And then you exec:

$ systemctl start [email protected] [email protected] 

or...

Target dependencies

You can create multiple units that links to a single target:

#/etc/systemd/system/bar.target [Unit] Description=bar target Requires=multi-user.target After=multi-user.target AllowIsolate=yes 

And then you just modify you .service units to be WantedBy=bar.target like:

#/etc/systemd/system/[email protected] [Unit] Description=script description %I  [Service] Type=simple ExecStart=/script.py %i Restart=on-failure  [Install] WantedBy=bar.target 

Then you just enable the foo services you want in parallel, and start the bar target like this:

$ systemctl daemon-reload $ systemctl enable [email protected] $ systemctl enable [email protected] $ systemctl start bar.target 

NOTE: that this works with any type of units not only template units.

Answer 2

You can use ExecStartPre or ExecStartPost for one of scripts

[Unit] Description=script description  [Service] Type=simple ExecStartPre=/script.py parameters1 ExecStart=/script.py parameters2 Restart=on-failure  [Install] WantedBy=multi-user.target