SystemD is the default service manager on most linux distos. It is capable of restarting services in case they crash. This makes it idea to running web server related processes on a VPS (among other things).

Create custom service

The configuration file for the service is located at /etc/systemd/system/<service-name>.service.

Following are the sample content for a web application binary which needs to auto-run the the background (restarted if needed).

[Unit]
Description=<service-name>
After=network.target

[Service]
ExecStart=</full/path/to/binary/or/script>
WorkingDirectory=</path/to/directory/containing/binary/or/script>
Type=simple
Restart=always

[Install]
WantedBy=default.target

Note: Any time the service file for any service changes, run the following command to reload.

$ systemctl daemon-reload