Comment 64 for bug 1789177

I confirmed that upgrading olso.messaging in n-ovs causes rabbitmq issue

Right after restarted n-ovs-agent, I can see a lot of errors in rabbitmq log[1]
which is the same as the error when rabbitmq failover issue ( the original issue of this LP )

Then after I upgraded oslo.messaging in neutron-api unit and restarted neutron-server, below errors are gone and I was able to create instance again.

After upgrading oslo.messaging in n-ovs only, exchange they communicate didn't match.
As changing exchanges they use depends on publisher-cosumer relation.

So I think there are two ways.
1. revert this patch for Q ( original failover problem will be there )
2. upgrade them with maintenance window

Thanks a lot

[1]
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=ERROR REPORT==== 3-Feb-2021::03:25:26 ===
Channel error on connection <0.2379.1> (10.0.0.32:60430 -> 10.0.0.34:5672, vhost: 'openstack', user: 'neutron'), channel 1:
{amqp_error,not_found,
            "no exchange 'reply_7da3cecc31b34bdeb96c866dc84e3044' in vhost 'openstack'",
            'basic.publish'}

10.0.0.32 is neutron-api unit