Binding in RabbitMQ does not work

[Dmitry Mescheryakov]

MOS Version: 9.1

After some unidentified failure binding in RabbitMQ between exchange 'neutron' and queue 'q-plugin' stopped working. Both rabbitmqctl console tool and web UI showed that it existed, but for the purpose of message routing RabbitMQ behaved as if the binding was missing. We found that out by posting a message to exchange 'neutron' with routing key 'q-plugin' via web UI. The UI responded with warning 'message was not routed', meaning that it was not delivered and was dropped instead. For comparison, we posted a message to another queue 'q-reports-plugin' via the same exchange 'neutron' and this time the message was delivered. During the meeting we have restarted neutron-server, which recreates the binding on start, but that did not help. The problem resolved only after we have restarted the whole RabbitMQ cluster.

Right now we do not have enough data to investigate the bug fully, as the only repro at customer's site was fixed because it was a production env. Possible leads:
 * look through the RabbitMQ's code related to bindings
 * look through the provided RabbitMQ logs to understand what led to the issue and try to reproduce it on our env.