[openstack-dev] auto-delete in amqp "reply_*" queues in OpenStack

Chris Friesen chris.friesen at windriver.com
Mon Mar 24 15:52:48 UTC 2014

On 03/24/2014 02:59 AM, Dmitry Mescheryakov wrote:
> Chris,
> In oslo.messaging a single reply queue is used to gather results from
> all the calls. It is created lazily on the first call and is used
> until the process is killed. I did a quick look at oslo.rpc from
> oslo-incubator and it seems like it uses the same pattern, which is
> not surprising since oslo.messaging descends from oslo.rpc. So if you
> restart some process which does rpc calls (nova-api, I guess), you
> should see one reply queue gone and another one created instead after
> some time.

Okay, that makes a certain amount of sense.

How does it work for queues used by both the controller and the compute 

If I do a controlled switchover from one controller to another (killing 
and restarting rabbit, nova-api, nova-conductor, nova-scheduler, 
neutron, cinder, etc.) I see that the number of reply queues drops from 
28 down to 5, but those 5 are all ones that existed before.

I assume that those 5 queues are (re)created by the services running on 
the compute nodes, but if that's the case then how would the services 
running on the controller node find out about the names of the queues?


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