Restart of neutron-ovs-agent may cause data plane breakage

[Slawek Kaplonski]

In case when neutron-ovs-agent is restarted and there is rabbitmq connectivity issue, traffic through provider networks may be broken. It is similar issue like described in https://launchpad.net/neutron/+bug/1803919 and then it was fixed by setting up rpc and checking if connectivity is fine before physical bridges were configured.
But later bug https://launchpad.net/neutron/+bug/1840443 came and fix for that https://github.com/openstack/neutron/commit/d41bd58f31e259fe408c8c059b31299fdfe81127 changed this order again. So now physical bridges are configured before rpc is configured so it may happen again that due to broken rpc channel correct flows will not be installed.

[LIU Yulong (dragon889)]

Does this fix https://review.opendev.org/#/c/733568/ solve the problem?

[Slawek Kaplonski (slaweq)]

Actually no. When I was checking issue which was fixed with https://review.opendev.org/#/c/733568/ I found that order of the operations during the initialization of the agent changed some time ago and that can potentially cause another break of the data plane when rabbitmq will be down.
But I didn't confirm that it will really happen.