Monit
An open source utility for managing and monitoring processes, programs, files, directories and filesystems
linux osx open-source monitoring process-mgmt c
Supervisor
Supervisor can manage application processes. It can start and stop a group of processes, restart processes if any of them terminate (keep-alive), start multiple instances of the same process (process pooling), automatically manage PID files, and much more! Very useful if you need to manage multiple processes for your application.
linux osx open-source process-mgmt python