Comment 0 for bug 1888395

it was working in queens but fails in train. nova compute at the target aborts with the exception:

Traceback (most recent call last):
  File "/usr/lib/python2.7/site-packages/oslo_messaging/rpc/server.py", line 165, in _process_incoming
    res = self.dispatcher.dispatch(message)
  File "/usr/lib/python2.7/site-packages/oslo_messaging/rpc/dispatcher.py", line 274, in dispatch
    return self._do_dispatch(endpoint, method, ctxt, args)
  File "/usr/lib/python2.7/site-packages/oslo_messaging/rpc/dispatcher.py", line 194, in _do_dispatch
    result = func(ctxt, **new_args)
  File "/usr/lib/python2.7/site-packages/nova/exception_wrapper.py", line 79, in wrapped
    function_name, call_dict, binary, tb)
  File "/usr/lib/python2.7/site-packages/oslo_utils/excutils.py", line 220, in __exit__
    self.force_reraise()
  File "/usr/lib/python2.7/site-packages/oslo_utils/excutils.py", line 196, in force_reraise
    six.reraise(self.type_, self.value, self.tb)
  File "/usr/lib/python2.7/site-packages/nova/exception_wrapper.py", line 69, in wrapped
    return f(self, context, *args, **kw)
  File "/usr/lib/python2.7/site-packages/nova/compute/utils.py", line 1372, in decorated_function
    return function(self, context, *args, **kwargs)
  File "/usr/lib/python2.7/site-packages/nova/compute/manager.py", line 219, in decorated_function
    kwargs['instance'], e, sys.exc_info())
  File "/usr/lib/python2.7/site-packages/oslo_utils/excutils.py", line 220, in __exit__ self.force_reraise()
  File "/usr/lib/python2.7/site-packages/oslo_utils/excutils.py", line 196, in force_reraise
    six.reraise(self.type_, self.value, self.tb) File "/usr/lib/python2.7/site-packages/nova/compute/manager.py", line 207, in decorated_function
    return function(self, context, *args, **kwargs)
  File "/usr/lib/python2.7/site-packages/nova/compute/manager.py", line 7007, in pre_live_migration
    bdm.save()
  File "/usr/lib/python2.7/site-packages/oslo_utils/excutils.py", line 220, in __exit__
    self.force_reraise()
  File "/usr/lib/python2.7/site-packages/oslo_utils/excutils.py", line 196, in force_reraise
    six.reraise(self.type_, self.value, self.tb)
  File "/usr/lib/python2.7/site-packages/nova/compute/manager.py", line 6972, in pre_live_migration
    migrate_data)
  File "/usr/lib/python2.7/site-packages/nova/virt/libvirt/driver.py", line 9190, in pre_live_migration
    instance, network_info, migrate_data)
  File "/usr/lib/python2.7/site-packages/nova/virt/libvirt/driver.py", line 9071, in _pre_live_migration_plug_vifs
    vif_plug_nw_info.append(migrate_vif.get_dest_vif())
  File "/usr/lib/python2.7/site-packages/nova/objects/migrate_data.py", line 90, in get_dest_vif
    vif['type'] = self.vif_type
  File "/usr/lib/python2.7/site-packages/oslo_versionedobjects/base.py", line 67, in getter
    self.obj_load_attr(name)
  File "/usr/lib/python2.7/site-packages/oslo_versionedobjects/base.py", line 603, in obj_load_attr
    _("Cannot load '%s' in the base class") % attrname)
NotImplementedError: Cannot load 'vif_type' in the base class

steps to reproduce:
- train centos 7 based deployment: 1 controller, 2 computes, libvirt + qemu-kvm, ceph shared storage, neutron with contrail vrouter virtual network;
- create and start a vm;
- live migrate it between computes.

expected result: vm migrates successfully.

rpm -qa | grep nova:

python2-novaclient-15.1.1-1.el7.noarch
openstack-nova-common-20.3.0-1.el7.noarch
python2-nova-20.3.0-1.el7.noarch
openstack-nova-compute-20.3.0-1.el7.noarch