PID files not being removed on shutdown

Jon Wood jon at
Tue Jun 18 12:41:20 UTC 2013


I'm quite consistently seeing an issue where Unicorn leaves its PID
files in place after a clean shut down, which is causing some issues
when deploying releases that update Unicorn config.

We're doing hot restarts with USR2+QUIT, and using Upstart for process
supervision based on the presence of a PID file (this admittedly might
be a mistake, but I've not seen any better solutions).

This works fine in the case of a hot restart since Unicorn correctly
updates the PID file, however when we change the configuration for
Unicorn shutting down the master process doesn't remove the PID file,
so the supervising Upstart script doesn't detect that the master has
been shut down and bring up a new one.

I've created a gist[1] of our Upstart and Unicorn configuration files.
As I say, we might just be doing something stupid here, but Google
doesn't seem to have shed any light on the issue.

Thanks for any help,


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