Running beat

celery -A proj beat -S percival.beat.Scheduler

Schedules live in Redis, managed by RedBeat, which is installed with the client. percival.beat.Scheduler is RedBeat with three additions:

• Crontabs follow their own timezone. Each schedule can have one, and daylight saving time is handled as wall clock time: "9:00 Europe/London" stays 9:00 local when the clocks change.
• A heartbeat. Beat writes one every tick, so the panel knows it's alive and whether your last change was picked up.
• Faster pickup. It checks for new schedules every 15 seconds instead of up to every 5 minutes.

Plain redbeat.RedBeatScheduler still works with everything the panel writes. You just lose the three things above.

Run one beat

As with any Celery beat, run exactly one. RedBeat takes a lock in Redis so a second beat waits instead of double firing. If beat is killed hard, the lock stays until it times out (about 25 minutes by default). The panel shows a banner when that happens.

Keep Redis persistent

Your schedules are stored in Redis, so turn on Redis persistence (AOF or RDB snapshots). If Redis loses its data, the schedules go with it.