Sort of. Openstack RPC-over-AMQP (oslo.messaging) automatically ack()'s all messages that are received. So, it becomes the responsibility of the sender to retry. For example, the scheduler in Nova does this. However, if the client fails before getting the message, AMQP will automatically requeue it and send it to another client. But that's an unlikely occurrence as it's queue-per-host so there wouldn't be a second client. Therefore, queues should be configured to be durable.
Hope it helps! -S ________________________________ From: Aaron Knister [[email protected]] Sent: Tuesday, October 14, 2014 12:00 PM To: Raghu Vadapalli Cc: <[email protected]> Subject: Re: [Openstack] Messaging reliability/durability expectations Thanks Raghu. I think I might not be asking the right questions. Part of my ignorance here comes from not understanding AMQP. I think really what I'm trying to figure out is whether openstack expects durable queues. It sounds like the answer is no but confirmation of this would be great. Even if it doesn't expect durable queues is there a noticeable advantage to openstack to have them? Thanks again! Sent from my iPhone On Oct 14, 2014, at 10:12 AM, Raghu Vadapalli <[email protected]<mailto:[email protected]>> wrote: — Raghu On Tuesday, Oct 14, 2014 at 7:49 AM, Aaron Knister <[email protected]<mailto:[email protected]>>, wrote: Thanks Remo, could you elaborate a little? Which is part of RabbitMQ? The HA layer or the message retransmission? I'm currently using qpid. Also, just so I'm clear, is it the openstack code or the low-level messaging drivers (rabbit, zmq, qpid) that retransmit on message delivery failure? Thanks! That should be the job messaging infrastructure provided by rabbit or qpid Raghu Sent from my iPhone On Oct 13, 2014, at 11:59 PM, Remo Mattei <[email protected]<mailto:[email protected]>> wrote: That is part of RabbitMQ and yes it will resend the msg. Remo On Oct 13, 2014, at 22:31, Aaron Knister <[email protected]<mailto:[email protected]>> wrote: Hi Everyone, I'm building a production-grade cloud where HA is a requirement. I'm currently working on implementing HA of the messaging layer and am not clear on what the expectations/assumptions are of the messaging layer regarding message durability and reliability. I've seen documentation scattered about that suggests OpenStack makes no assumptions that messages will be delivered or will need to persist for any period of time (https://openstack.redhat.com/Highly_Available_Qpid_for_OpenStack). What's the consequence of RPC message loss within openstack? Is it true that it will resend messages? Thanks! -Aaron !DSPAM:1,543c9c2325772110695322! _______________________________________________ Mailing list: http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack Post to : [email protected]<mailto:[email protected]> Unsubscribe : http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack !DSPAM:1,543c9c2325772110695322!
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