During live-migration nova service fails with "Exception: Unsupported VIF type unbound convert '_nova_to_osvif_vif_unbound' in RHOSP10.

Issue

• After live-migration of an instance and reboot of the compute host, nova-compute compute doesn't start.

In /var/log/nova/nova-compute.log, we found this error message:
ovaException: Unsupported VIF type unbound convert '_nova_to_osvif_vif_unbound'


[root@oscar02com001 ~]# systemctl status openstack-nova-compute.service
● openstack-nova-compute.service - OpenStack Nova Compute Server
   Loaded: loaded (/usr/lib/systemd/system/openstack-nova-compute.service; enabled; vendor preset: disabled)
   Active: activating (start) since Wed 2019-08-07 15:44:17 CEST; 1s ago
 Main PID: 130511 (nova-compute)
    Tasks: 1
   Memory: 66.7M
   CGroup: /system.slice/openstack-nova-compute.service
           └─130511 /usr/bin/python2 /usr/bin/nova-compute

Aug 07 15:44:17 oscar02com001.tc.lab.int.corp systemd[1]: Starting OpenStack Nova Compute Server...

• nova-compute service gets stuck in starting state post VM migration in RHOSP10.
• During live-migration nova service fails with Exception: Unsupported VIF type unbound convert '_nova_to_osvif_vif_unbound'.