[Openstack] Messaging reliability/durability expectations
chris.friesen at windriver.com
Tue Oct 14 20:48:49 UTC 2014
On 10/14/2014 09:39 AM, Sandy Walsh wrote:
> 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.
Oddly, the default in oslo.messaging is for them to not be durable.
And as Gordon pointed out, queues are auto-deleted leading to this bug:
And then there are issues about who should re-create queues on amqp
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