Hi,
I’ve been chasing a bug in ironic’s neutron agent for the last few days and I think its time to ask for some advice.
Specifically, I was asked to debug why a set of controllers was using so much RAM, and the answer was that rabbitmq had a queue called ironic-neutron-agent-heartbeat.info with 800,000 messages enqueued. This notification queue is used by ironic’s neutron agent to calculate the hash ring. I have been able to duplicate this issue in a stock kolla-ansible install with ironic turned on but no bare metal nodes enrolled in ironic. About 0.6 messages are queued per second.
I added some debugging code (hence the thread yesterday about mangling the code kolla deploys), and I can see that the messages in the queue are being read by the ironic neutron agent and acked correctly. However, they are not removed from the queue.
You can see your queue size while using kolla with this command:
docker exec rabbitmq rabbitmqctl list_queues messages name messages_ready consumers | sort -n | tail -1
My stock install that’s been running for about 12 hours currently has 8,244 messages in that queue.
Where I’m a bit stumped is I had assumed that the messages weren’t being acked correctly, which is not the case. Is there something obvious about notification queues like them being persistent that I’ve missed in my general ignorance of the underlying implementation of notifications?
Thanks, Michael