Description

Directly from the systemd documentation

A unit configuration file whose name ends in ".service" encodes information about a process controlled and supervised by systemd.

Below is an example of how I'd set one up

Go wild here

some.service

[Unit]
Description=Some service template
After=network.target    # Means "start when network ready".
                        # Can be replaced with the name of some other service
                        # to wait for.
StartLimitIntervalSec=0

[Service]
Type=simple     # One of simple, exec, forking, oneshot, dbus, notify,
                # notify-reload, or idle.
Restart=always  # One of always, on-failure, on-success, on-abnormal,
                # on-watchdog, on-abort.
RestartSec=1    # Time to sleep before attempting a restart.
User=kblagoev   # User to run service under.
ExecStart=/usr/bin/env node /path/to/server.js # The actual command to run.

[Install]
WantedBy=multi-user.target

To make use of it:

$ cp <some.service> /etc/systemd/system/<some.service>
$ systemctl start <some.service>
$ systemctl enable <some.service> # This will ensure automatic start on boot

Notes

Restart limit

By default, systemd gives up restarting the service if it fails to start more than 5 times within 10 seconds. This is defined in the following variables

[Unit]
StartLimitBurst=5
StartLimitIntervalSec=10

This is avoided by setting StartLimitIntervalSec=0. This will assure systemd attempts restarting forever. The idea is that, as long as StartLimitIntervalSec is less than RestartSec * StartLimitBurst, the service will be restarted indefinitely.

As an alternative, you can leave the default settings, and ask systemd to restart your service if the start limit is reached, using StartLimitAction=reboot.

Limited automatic restart with a valid StartLimitIntervalSec

To have a service restart 3 times at 90 second intervals include the following lines in your systemd service file:

[Unit]
StartLimitIntervalSec=400
StartLimitBurst=3
[Service]
Restart=always
RestartSec=90