restartd - A process-restarting daemon
This is a new upstream for the restartd(8) daemon, which was originally debian-only. It will host the new developments for this project.
From the man page:
Restartd is a daemon for checking running and not running processes. It reads the /proc directory every n seconds and does a POSIX regexp on the process names. You can execute a script or a program if the process is or is not running.