How to automatically restart a linux background process if it fails?

Solution 1:

The easiest way would be to add it to /etc/inittab, which is designed to do this sort of thing:

respawn If the process does not exist, start the process. Do not wait for its termination (continue scanning the /etc/inittab file). Restart the process when it dies. If the process exists, do nothing and continue scanning the /etc/inittab file.

For example, you could do this:

# Run my stuff
myprocess:2345:respawn:/bin/myprocess

Solution 2:

Buildroot has three possible init systems, so there are three ways to do this:

BusyBox init

With this, one adds an entry to /etc/inittab.

::respawn:/bin/myprocess

Note that BusyBox init has an idiosyncratic /etc/inittab format. The second field is meaningless, and the first field is not an ID but a device basename.

Linux "System V" init

Again, one adds an entry to /etc/inittab.

myprocess:2345:respawn:/bin/myprocess

systemd

One writes a unit file in, say, /etc/systemd/system/myprocess.service:

[Unit]
Description=My Process

[Service]
ExecStart=/bin/myprocess
Restart=always

[Install]
WantedBy=multi-user.target

Enable this to autostart at bootup with:

systemctl enable myprocess.service

Start it manually with:

systemctl start myprocess.service

Further reading

• "3.1.3 init system". The Buildroot user manual.