Comment 3 for bug 1784579

@dan
binding failed is an actual semi-valid vif type in neutron
https://github.com/openstack/neutron-lib/blob/master/neutron_lib/api/definitions/portbindings.py#L86
i say semi valid as it represent the fact that neutron was not able to find an ml2 capable of configuring the newtorking on the host for that interface.

we would need both the q-agt log and the q-svc log to determine why the binding failed in neutron.
the actull error shoudl be in the neutron server log (q-svc) but it could be a reuslt of an error in the neutron ovs l2 agent (q-agt). for example if the q-agt was stopped the binding would fail for that host.

i would also guess we are missing binding the port back to the souce in the cases where the prelive migration fails to bind it to the dest node.