text: Celery 1.0.6 (stable) documentation
  You can schedule tasks to run at intervals like cron.)
  If you want a little more control over when the task is executed, for example, a particular time of day or day of the week, you can use crontab to set the run_every property:
  from celery.task import PeriodicTask from celery.task.schedules import crontab class EveryMondayMorningTask(PeriodicTask): run_every = crontab(hour=7, minute=30, day_of_week=1) def run(self, **kwargs): logger = self.get_logger(**kwargs) logger.info("Execute every Monday at 7:30AM.")
  If you want to use periodic tasks you need to start the celerybeat service. You have to make sure only one instance of this server is running at any time, or else you will end up with multiple executions of the same task.
  To start the celerybeat service:
  $ celerybeat
  or if using Django:
  $ python manage.py celerybeat
  You can also start celerybeat with celeryd by using the -B option, this is convenient if you only have one server:
  $ celeryd -B
  or if using Django:
  $ python manage.py celeryd -B