Open Stack

On 11/13/2012 01:24 PM, Vishvananda Ishaya wrote:
> 
> On Nov 13, 2012, at 10:14 AM, Ray Pekowski <pekowski at gmail.com
> <mailto:pekowski at gmail.com>> wrote:
>>
>> My question is whether anyone thinks it is a worthwhile effort to
>> investigate code changes to the Openstack RPC that would make the RPC
>> responses flow on static exchanges and queues?
>>
> 
> Yes I think this is worthwhile. A few people have tried this out and
> there doesn't seem to be any reason why this wouldn't work. This should
> be done in oslo-incubator (formerly openstack-common)

The dynamic creation is of *queues*, right?  Not of exchanges and queues
as specified before?  It only seems valuable to have dynamic queues for
responses, which I'm pretty sure is how it works.

The use of temporary queues for responses is discussed in the AMQP spec
(is at least in the 0-9-1 version I just pulled up), so what we're doing
seems to be recommended in general.

My concern with using static reply queues is the uncertainty that comes
along with that.  When you create a temporary queue *only* for the
purpose of receiving a response, you know that the only thing you're
going to get is the response.  When you start leaving queues around and
reusing them, it's not guaranteed anymore.  That would be my biggest
concern.

It may be doable in a way that's safe enough.  We just need to be *very*
careful.

I'm also curious about the volume of rpc calls you were doing in your
testing, and how that may relate to the size of a deployment (or the
size of a single cell in the upcoming cells feature).

-- 
Russell Bryant