How to use systemd to have your apps running in the background forever

If you want your apps to run forever, that is:

• run when the program crashes
• starts when the operating system starts

then you'd simply create a new systemd unit. To do that, we'll create a systemd unit file.

For a service named "foobar", we will create it in /lib/systemd/system/foobar.service.

And the content would look like so:

[Unit]
Description=Does something
After=network.target
[Service]
Type=simple
User=root
# Change the following two configs
WorkingDirectory=/the/working/directory
ExecStart=/path/to/program
Restart=always
[Install]
WantedBy=multi-user.target

Then restart the systemctl daemon.

systemctl daemon-reload

Then, to run your app as a service, invoke the following command.

sudo systemctl start foobar

And then, to ensure that it starts on boot, invoke the following command.

sudo systemctl enable foobar

Whether things went well or not, you should still see absolutely nothing.

If your application is a web server, you can ping it with a cURL request, to see if it's working.

If it isn't, then you can take a look at the logs to see what may have gone wrong.

Invoke the following command:

sudo journalctl -xe

Hopefully you should have a good idea on how to get things working.

Digital ocean has a comprehensive article on what systemd is, and how you can take full advantage of it.