I've been using celery (the async task queue in python) in a Django project with Redis as a results backend and broker for a few years now - today I tried switching the backend / broker to AWS's ElastiCache Redis, but the celery worker goes into an infinite startup and shutdown cycle as seen below in the log file. I have also successfully connected to the Redis instance from the same machine running celery and done some basic SET and GET operations successfully.
My current setup is:
celery worker --concurrency=3 --queues=general --events --loglevel=DEBUG --beat --schedule=/tmp/celerybeat-schedule --pidfile=/tmp/celery.main.pid --config=celeryconfig
import os
from django.conf import settings
from celery import Celery, Task, chain
os.environ.setdefault('DJANGO_SETTINGS_MODULE', 'settings')
celery = Celery()
celery.config_from_object("celeryconfig")
celery.autodiscover_tasks(settings.INSTALLED_APPS, related_name='tasks')
BROKER_URL = "redis://staging-redis.abcde.clustercfg.use1.cache.amazonaws.com:6379/0"
CELERY_TIMEZONE = u'America/Los_Angeles'
CELERYD_HIJACK_ROOT_LOGGER = True
CELERY_IMPORTS = (
"app.tasks"
)
CELERYD_TASK_TIME_LIMIT = 35 # seconds
CELERYD_TASK_SOFT_TIME_LIMIT = 25 # seconds
DJANGO_SETTINGS_MODULE = "settings"
CELERY_RESULT_BACKEND = BROKER_URL
CELERY_ROUTES = {
'app.tasks.my_task': {'queue': 'general'}
}
-------------- celery@ip-10-20-21-9 v3.1.24 (Cipater)
---- **** -----
--- * *** * -- Linux-3.13.0-74-generic-x86_64-with-Ubuntu-14.04-trusty
-- * - **** ---
- ** ---------- [config]
- ** ---------- .> app: default:0x7f7dc6d71650 (.default.Loader)
- ** ---------- .> transport: redis://staging-redis.abcde.clustercfg.use1.cache.amazonaws.com:6379/0
- ** ---------- .> results: redis://staging-redis.abcde.clustercfg.use1.cache.amazonaws.com:6379/0
- *** --- * --- .> concurrency: 3 (prefork)
-- ******* ----
--- ***** ----- [queues]
-------------- .> general exchange=general(direct) key=general
[tasks]
. app.tasks.my_task
. celery.backend_cleanup
. celery.chain
. celery.chord
. celery.chord_unlock
. celery.chunks
. celery.group
. celery.map
. celery.starmap
[2017-06-16 14:33:12,658: DEBUG/MainProcess] removing tasks from inqueue until task handler finished
[2017-06-16 14:33:15,110: DEBUG/MainProcess] | Worker: Preparing bootsteps.
[2017-06-16 14:33:15,112: DEBUG/MainProcess] | Worker: Building graph...
[2017-06-16 14:33:15,113: DEBUG/MainProcess] | Worker: New boot order: {Timer, Hub, Queues (intra), Pool, Autoscaler, StateDB, Autoreloader, Beat, Consumer}
[2017-06-16 14:33:15,118: DEBUG/MainProcess] | Consumer: Preparing bootsteps.
[2017-06-16 14:33:15,118: DEBUG/MainProcess] | Consumer: Building graph...
[2017-06-16 14:33:15,127: DEBUG/MainProcess] | Consumer: New boot order: {Connection, Events, Mingle, Tasks, Control, Heart, Agent, Gossip, event loop}
[2017-06-16 14:33:15,137: DEBUG/MainProcess] | Worker: Starting Hub
[2017-06-16 14:33:15,137: DEBUG/MainProcess] ^-- substep ok
[2017-06-16 14:33:15,137: DEBUG/MainProcess] | Worker: Starting Pool
[2017-06-16 14:33:15,287: DEBUG/MainProcess] ^-- substep ok
[2017-06-16 14:33:15,288: DEBUG/MainProcess] | Worker: Starting Consumer
[2017-06-16 14:33:15,288: DEBUG/MainProcess] | Consumer: Starting Connection
[2017-06-16 14:33:15,315: INFO/MainProcess] Connected to redis://staging-redis.abcde.clustercfg.use1.cache.amazonaws.com:6379/0
[2017-06-16 14:33:15,315: DEBUG/MainProcess] ^-- substep ok
[2017-06-16 14:33:15,316: DEBUG/MainProcess] | Consumer: Starting Events
[2017-06-16 14:33:15,328: DEBUG/MainProcess] | Worker: Closing Hub...
[2017-06-16 14:33:15,328: DEBUG/MainProcess] | Worker: Closing Pool...
[2017-06-16 14:33:15,328: DEBUG/MainProcess] | Worker: Closing Consumer...
[2017-06-16 14:33:15,329: DEBUG/MainProcess] | Worker: Stopping Consumer...
[2017-06-16 14:33:15,329: DEBUG/MainProcess] | Worker: Stopping Pool...
[2017-06-16 14:33:16,338: DEBUG/MainProcess] | Worker: Stopping Hub...
[2017-06-16 14:33:16,338: DEBUG/MainProcess] | Consumer: Shutdown Gossip...
[2017-06-16 14:33:16,338: DEBUG/MainProcess] | Consumer: Shutdown Heart...
[2017-06-16 14:33:16,339: DEBUG/MainProcess] | Consumer: Shutdown Control...
[2017-06-16 14:33:16,339: DEBUG/MainProcess] | Consumer: Shutdown Tasks...
[2017-06-16 14:33:16,339: DEBUG/MainProcess] | Consumer: Shutdown Events...
[2017-06-16 14:33:16,340: DEBUG/MainProcess] | Consumer: Shutdown Connection...
-------------- celery@ip-10-20-21-9 v3.1.24 (Cipater)
---- **** -----
--- * *** * -- Linux-3.13.0-74-generic-x86_64-with-Ubuntu-14.04-trusty
-- * - **** ---
- ** ---------- [config]
- ** ---------- .> app: default:0x7fdc3b019650 (.default.Loader)
- ** ---------- .> transport: redis://staging-redis.abcde.clustercfg.use1.cache.amazonaws.com:6379/0
- ** ---------- .> results: redis://staging-redis.abcde.clustercfg.use1.cache.amazonaws.com:6379/0
- *** --- * --- .> concurrency: 3 (prefork)
-- ******* ----
--- ***** ----- [queues]
-------------- .> general exchange=general(direct) key=general
[tasks]
. app.tasks.my_task
. celery.backend_cleanup
. celery.chain
. celery.chord
. celery.chord_unlock
. celery.chunks
. celery.group
. celery.map
. celery.starmap
[2017-06-16 14:33:12,658: DEBUG/MainProcess] removing tasks from inqueue until task handler finished
[2017-06-16 14:33:15,110: DEBUG/MainProcess] | Worker: Preparing bootsteps.
[2017-06-16 14:33:15,112: DEBUG/MainProcess] | Worker: Building graph...
[2017-06-16 14:33:15,113: DEBUG/MainProcess] | Worker: New boot order: {Timer, Hub, Queues (intra), Pool, Autoscaler, StateDB, Autoreloader, Beat, Consumer}
[2017-06-16 14:33:15,118: DEBUG/MainProcess] | Consumer: Preparing bootsteps.
[2017-06-16 14:33:15,118: DEBUG/MainProcess] | Consumer: Building graph...
[2017-06-16 14:33:15,127: DEBUG/MainProcess] | Consumer: New boot order: {Connection, Events, Mingle, Tasks, Control, Heart, Agent, Gossip, event loop}
[2017-06-16 14:33:15,137: DEBUG/MainProcess] | Worker: Starting Hub
[2017-06-16 14:33:15,137: DEBUG/MainProcess] ^-- substep ok
[2017-06-16 14:33:15,137: DEBUG/MainProcess] | Worker: Starting Pool
[2017-06-16 14:33:15,287: DEBUG/MainProcess] ^-- substep ok
[2017-06-16 14:33:15,288: DEBUG/MainProcess] | Worker: Starting Consumer
[2017-06-16 14:33:15,288: DEBUG/MainProcess] | Consumer: Starting Connection
[2017-06-16 14:33:15,315: INFO/MainProcess] Connected to redis://staging-redis.abcde.clustercfg.use1.cache.amazonaws.com:6379/0
[2017-06-16 14:33:15,315: DEBUG/MainProcess] ^-- substep ok
[2017-06-16 14:33:15,316: DEBUG/MainProcess] | Consumer: Starting Events
[2017-06-16 14:33:15,328: DEBUG/MainProcess] | Worker: Closing Hub...
[2017-06-16 14:33:15,328: DEBUG/MainProcess] | Worker: Closing Pool...
[2017-06-16 14:33:15,328: DEBUG/MainProcess] | Worker: Closing Consumer...
[2017-06-16 14:33:15,329: DEBUG/MainProcess] | Worker: Stopping Consumer...
[2017-06-16 14:33:15,329: DEBUG/MainProcess] | Worker: Stopping Pool...
[2017-06-16 14:33:16,338: DEBUG/MainProcess] | Worker: Stopping Hub...
[2017-06-16 14:33:16,338: DEBUG/MainProcess] | Consumer: Shutdown Gossip...
[2017-06-16 14:33:16,338: DEBUG/MainProcess] | Consumer: Shutdown Heart...
[2017-06-16 14:33:16,339: DEBUG/MainProcess] | Consumer: Shutdown Control...
[2017-06-16 14:33:16,339: DEBUG/MainProcess] | Consumer: Shutdown Tasks...
[2017-06-16 14:33:16,339: DEBUG/MainProcess] | Consumer: Shutdown Events...
[2017-06-16 14:33:16,340: DEBUG/MainProcess] | Consumer: Shutdown Connection...
## And again...
Looks like the issue arose because I was trying to use a Redis Cluster as the broker and backend which isn't supported out of the box - in a more basic test setup, the SETNX command was failing on celery startup because it seems the command is not supported by Redis Clusters.
I still need to do some research to see if it's possible to use a Redis Cluster as a Celery backend and broker.