InstanceHA with OVN-DVR fails to migrate an instance to a new host on hypervisor failure in Red Hat OpenStack Platform 13

Issue

InstanceHA (Instance High Availability) with OVN-DVR fails to migrate an instance to a new host on hypervisor failure with Virtual Interface creation failed.

Looking at /var/log/containers/nova/nova-compute.log on the destination host, one can see that nova receives a notification that the port was plugged:

2019-10-30 10:58:48.571 1 INFO os_vif [req-6d406268-e8c4-459a-8a30-b9a57f39f885 bd91b36e1fbe4721aec937e03128d6c6 33eba5123397495d9e36d08cb0b2d2da - default default] Successfully plugged vif VIFOpenVSwitch(active=False,address=fa:16:3e:4c:96:52,bridge_name='br-int',has_traffic_filtering=True,id=264a75da-9590-4066-97b6-dabd22c14b43,network=Network(197c1f37-7b65-44a3-80b0-368cff9bc9cb),plugin='ovs',port_profile=VIFPortProfileOpenVSwitch,preserve_on_delete=False,vif_name='tap264a75da-95')

And one observes a timeout:

2019-10-30 11:03:49.760 1 WARNING nova.virt.libvirt.driver [req-6d406268-e8c4-459a-8a30-b9a57f39f885 bd91b36e1fbe4721aec937e03128d6c6 33eba5123397495d9e36d08cb0b2d2da - default default] [instance: 55e5beaa-8f4a-447d-809e-28654f9aea90] Timeout waiting for [('network-vif-plugged', u'264a75da-9590-4066-97b6-dabd22c14b43')] for instance with vm_state active and task_state rebuild_spawning.: Timeout: 300 seconds

And then VIF plugging fails:

2019-10-30 11:03:50.592 1 ERROR nova.compute.manager [instance: 55e5beaa-8f4a-447d-809e-28654f9aea90]     raise exception.VirtualInterfaceCreateException()
2019-10-30 11:03:50.592 1 ERROR nova.compute.manager [instance: 55e5beaa-8f4a-447d-809e-28654f9aea90] VirtualInterfaceCreateException: Virtual Interface creation failed