Comment 2 for bug 1892361

Additional data point: the behaviour changes when only restarting nova-compute -- the pci device allocation changes to a type-VF device.

However, spawning an instance still fails with VIF creation error in this case:

2020-08-20 13:47:41.505 681090 ERROR nova.compute.manager [req-39da5984-92fc-44d9-976d-2bac4279497e ddcfb3640535428798aa3c8545362bd4 dd99e7950a5b46b5b924ccd1720b6257 - 015e4fd7db304665ab5378caa691bb8b 015e4fd7db304665ab5378caa691bb8b] [i
nstance: 1b22a515-3ddc-4c5b-a5d6-537d98a4d990] Failed to allocate network(s): VirtualInterfaceCreateException: Virtual Interface creation failed
2020-08-20 13:47:41.505 681090 ERROR nova.compute.manager [instance: 1b22a515-3ddc-4c5b-a5d6-537d98a4d990] Traceback (most recent call last):
2020-08-20 13:47:41.505 681090 ERROR nova.compute.manager [instance: 1b22a515-3ddc-4c5b-a5d6-537d98a4d990] File "/usr/lib/python2.7/dist-packages/nova/compute/manager.py", line 2054, in _build_and_run_instance
2020-08-20 13:47:41.505 681090 ERROR nova.compute.manager [instance: 1b22a515-3ddc-4c5b-a5d6-537d98a4d990] block_device_info=block_device_info)
2020-08-20 13:47:41.505 681090 ERROR nova.compute.manager [instance: 1b22a515-3ddc-4c5b-a5d6-537d98a4d990] File "/usr/lib/python2.7/dist-packages/nova/virt/libvirt/driver.py", line 3147, in spawn
2020-08-20 13:47:41.505 681090 ERROR nova.compute.manager [instance: 1b22a515-3ddc-4c5b-a5d6-537d98a4d990] destroy_disks_on_failure=True)
2020-08-20 13:47:41.505 681090 ERROR nova.compute.manager [instance: 1b22a515-3ddc-4c5b-a5d6-537d98a4d990] File "/usr/lib/python2.7/dist-packages/nova/virt/libvirt/driver.py", line 5644, in _create_domain_and_network
2020-08-20 13:47:41.505 681090 ERROR nova.compute.manager [instance: 1b22a515-3ddc-4c5b-a5d6-537d98a4d990] raise exception.VirtualInterfaceCreateException()
2020-08-20 13:47:41.505 681090 ERROR nova.compute.manager [instance: 1b22a515-3ddc-4c5b-a5d6-537d98a4d990] VirtualInterfaceCreateException: Virtual Interface creation failed