Pulp

Pulp 2.16.4 has this issue https://github.com/celery/celery/issues/3620. It was fixed in celery 4.1. You need multiple tasks in the queue upon initial startup to reproduce this issue. You can also see more discussion about this issue here: https://github.com/celery/celery/pull/3752 and here https://github.com/celery/celery/issues/4109#issuecomment-314367686. I implemented this fix in my lab environment and it resolved my issue.

1. Problem with pulp_resource_manager service
   Jul 25 06:10:03 pulp-lab pulp[17698]: celery.worker:CRITICAL: (17698-58784) File "/usr/lib64/python2.7/site-packages/billiard/pool.py", line 1486, in apply_async
   Jul 25 06:10:03 pulp-lab pulp[17698]: celery.worker:CRITICAL: (17698-58784) self._quick_put((TASK, (result._job, None, func, args, kwds)))
   Jul 25 06:10:03 pulp-lab pulp[17698]: celery.worker:CRITICAL: (17698-58784) TypeError: 'NoneType' object is not callable

1. Here is the fix that was ultimately implemented which moves the consumption step below the object registration in worker/loops.py.
   - consumer.consume()
   - obj.on_ready()
   obj.controller.register_with_event_loop(hub)
   obj.register_with_event_loop(hub)
   + consumer.consume()
   + obj.on_ready()