systemd service won't start at boot/restart

Question

I'm really getting crazy trying to figure out why my systemd service won't start at boot, or whenever the ruby script associated fails (like what should do in my intention). I'm running it on a EC2 Ubuntu instance.

Here's the code of the service:

[Unit]
Description=Test

[Service]
User=ubuntu
Type=simple
ExecStart=/usr/bin/ruby /home/ubuntu/main/test.rb
Restart=on-failure
RestartSec=1s

[Install]
WantedBy=multi-user.target

I tried changing the target, or the user name, or the type...nothing happens. And the journal doesn't give me any particular info. The service works smoothly if I start it.

But if the script fails, or whenever I kill it to test it, it just ignore the restart thing.

Answer 1

This sounds like a dependence issue.

Systemd is running and your script needs Ruby running beforehand to execute. So on startup this service could be running before Ruby loads/finishes. And that's why you can run it after the box is up and running.

Look at adding under [Unit] 'After=' whatever the service name is for the Ruby environment. (I'm not sure what that would be.)

Then Systemd should wait for Ruby to load before trying to load up the service.

Look at your Ruby script and see what dependencies it may need. For example, maybe it needs the network up and running beforehand. Under [Unit] you can add 'After=' and then the needed dependence.

After=network.target

This is why after the box is up and running you can start the service, the needed dependencies have loaded.