celery sometimes hangs

[Thomas De Schampheleire]

Hi,

We are running Kallithea (some older version, 0.2.1 based) with
Celery, and sometimes the Celery workers just hang. This is observed
by e-mails not being received anymore. Restarting celery, or sending
'kill -SIGUSR1' to one of them, resolves the problem.

There are several reports on the internet about such problems, but
could be due to various reasons. Before digging deeper, I would like
to hear if some of you have or are experiencing the same thing, and
whether you have solutions.

This is celery 2.2.10, librabbitmq 1.6.1 and RabbitMQ 3.5.0.

Thanks,
Thomas