Celery : cannot shutdown celery due to PID changes - celery

Question

I'm using Cerely to manage delayed task on my django project.
I got problem when I tried to shutdown celery as suggested in the manual.
>> ps auxww | grep 'celery worker' | awk '{print $2}' | xargs kill -9
kill: No such process
>> ps auxww | grep 'celery worker' | awk '{print $2}
28630
>> ps auxww | grep 'celery worker' | awk '{print $2}
28633
PID continuosly changes and it makes hard to send killing signal.
How can I solve this problem? Thanks in advance.
[ Update ]
django settings.py
import djcelery
djcelery.setup_loader()
BROKER_URL = 'amqp://guest:guest#localhost:5672/' # Using RabbitMQ
CELERYD_MAX_TASKS_PER_CHILD = 1
PID check (After reboot)
>> ps auxww | grep 'celery worker' | awk '{print $2}'
3243
>> manage.py celery worker --loglevel=info
celery#{some id value}.... ready
>> ps auxww | grep 'celery worker' | awk '{print $2}'
3285
3293
3296
>> ps auxww | grep 'celery worker' | awk '{print $2}' | xargs kill -9
kill: No such process
>> ps auxww | grep 'celery worker' | awk '{print $2}'
3321
>> ps auxww | grep 'celery worker' | awk '{print $2}'
3324
Question
At least, one celery worker remains even though rebooted. And its PID changes continuously.
Celery daemon executes two workers at once. How can I fix it to only one worker ?

Answer 1

It is doing precisely what you asked for with the CELERYD_MAX_TASKS_PER_CHILD setting:
Maximum number of tasks a pool worker process can execute before it’s replaced with a new one.
Apparently you wanted to run one worker process, but that is controlled by a different setting, namely CELERYD_CONCURRENCY.
So, replace
CELERYD_MAX_TASKS_PER_CHILD = 1
with
CELERYD_CONCURRENCY = 1