How to keep Supervisord running unconditionally?

Question

In the Supervisord conf files you can specify to autorestart a certain program with:

autorestart=true

But is there an equivalent for [Supervisord] itself? What is the recommended method of making sure Supervisord continues running unconditionally, especially if the Supervisord process gets killed.

Thanks!

Answer 1

Actually your question is a particular application of the famous "Quis custodiet ipsos custodes?" that is "Who will guard the guards?".

In a modern Linux system the central guarding point is init process (the process number 1). If init dies, the Linux kernel immediately panics, and thus you have to go to your data center (I mean go afoot) and press reset button. There're a lot of alternative init implementations, here is one of those "comparison tables" :)

The precise answer how to configure a particular init implementation depends on what init version you use in that system. For example systemd has its own machinery for configure service restart upon their deaths (directives Restart=, RestartSec=, WatchdogSec= etc in a corresponding unit-file. Other init implementations like Ubuntu Upstart also has its analogues (respawn directive in a service configuration file). Even old good SysV init has respawn option for a service line in /etc/inittab, but usually user-level services aren't started directly inittab, only virtual console managers (getty, mgetty etc)