[Openstack] [nova] why does notification use a "topic" exchange instead of "fanout"?

Russell Bryant rbryant at redhat.com
Thu May 10 05:35:31 UTC 2012


On 05/09/2012 03:17 PM, Tihomir Trifonov wrote:
> Hi Doug,
> 
> not sure if you've hit the same problem, but I've spent some time on
> that when I started using RabbitMQ. As I see from the example, you've
> provided:
> 
> queue = Queue(name='notifications.info',
> 
>                   exchange=Exchange(name='nova'...
> 
> 
> 
> So you set explicitly a name for the queue. If you have two queues
> declared with the same name, when they are bound to an Exchange,
> actually each message is received only by the one queue at a time.

To be a bit pedantic, the result is that there is only one queue and two
consumers from that queue.  Only one consumer gets each message.  When
there is more than one consumer from the same queue, messages will be
distributed in a round-robin fashion.

-- 
Russell Bryant




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