How do I restart celery workers gracefully?

If you're going the kill route, pgrep to the rescue:

kill -9 `pgrep -f celeryd`

Mind you, this is not a long-running task and I don't care if it terminates brutally. Just reloading new code during dev. I'd go the restart service route if it was more sensitive.

According to https://docs.celeryq.dev/en/stable/userguide/workers.html#restarting-the-worker you can restart a worker by sending a HUP signal

 ps auxww | grep celeryd | grep -v "grep" | awk '{print $2}' | xargs kill -HUP

celery multi start 1 -A proj -l info -c4 --pidfile=/var/run/celery/%n.pid
celery multi restart 1 --pidfile=/var/run/celery/%n.pid

http://docs.celeryproject.org/en/latest/userguide/workers.html#restarting-the-worker

You can do:

celery multi restart w1 -A your_project -l info  # restart workers

Example