How to restart Celery gracefully without delaying tasks

Question

We use Celery with our Django webapp to manage offline tasks; some of these tasks can run up to 120 seconds.

Whenever we make any code modifications, we need to rest

Answer 1

Can you launch it with a custom pid file name. Possibly timestamped, and key off of that to know which PID to kill?

CELERYD_PID_FILE="/var/run/celery/%n_{timestamp}.pid"

^I dont know the timestamp syntax but maybe you do or you can find it?

then use the current system time to kill off any old pids and launch a new one?