Comment 4 for bug 1957939

Looks like it's a config issue, your VIF creation fails when you resize :

2022-01-12 16:27:06.063 7 ERROR nova.compute.manager [req-ea986ad9-09c8-4f2e-a685-b1535a4b1601 a877cc12f6b84f9c966a1b21b8cf0dbf 9437e136467242b2b67c35d36a2dcfa0 - default default] [instance: c303e65f-f34c-45ab-bc94-885088537c4c] Fa
iled to allocate network(s): nova.exception.VirtualInterfaceCreateException: Virtual Interface creation failed
2022-01-12 16:27:06.063 7 ERROR nova.compute.manager [instance: c303e65f-f34c-45ab-bc94-885088537c4c] Traceback (most recent call last):
2022-01-12 16:27:06.063 7 ERROR nova.compute.manager [instance: c303e65f-f34c-45ab-bc94-885088537c4c] File "/var/lib/kolla/venv/lib/python3.6/site-packages/nova/virt/libvirt/driver.py", line 7233, in _create_guest_with_network
2022-01-12 16:27:06.063 7 ERROR nova.compute.manager [instance: c303e65f-f34c-45ab-bc94-885088537c4c] post_xml_callback=post_xml_callback)
2022-01-12 16:27:06.063 7 ERROR nova.compute.manager [instance: c303e65f-f34c-45ab-bc94-885088537c4c] File "/usr/lib64/python3.6/contextlib.py", line 88, in __exit__
2022-01-12 16:27:06.063 7 ERROR nova.compute.manager [instance: c303e65f-f34c-45ab-bc94-885088537c4c] next(self.gen)
2022-01-12 16:27:06.063 7 ERROR nova.compute.manager [instance: c303e65f-f34c-45ab-bc94-885088537c4c] File "/var/lib/kolla/venv/lib/python3.6/site-packages/nova/compute/manager.py", line 479, in wait_for_instance_event
2022-01-12 16:27:06.063 7 ERROR nova.compute.manager [instance: c303e65f-f34c-45ab-bc94-885088537c4c] actual_event = event.wait()
2022-01-12 16:27:06.063 7 ERROR nova.compute.manager [instance: c303e65f-f34c-45ab-bc94-885088537c4c] File "/var/lib/kolla/venv/lib/python3.6/site-packages/eventlet/event.py", line 125, in wait
2022-01-12 16:27:06.063 7 ERROR nova.compute.manager [instance: c303e65f-f34c-45ab-bc94-885088537c4c] result = hub.switch()
2022-01-12 16:27:06.063 7 ERROR nova.compute.manager [instance: c303e65f-f34c-45ab-bc94-885088537c4c] File "/var/lib/kolla/venv/lib/python3.6/site-packages/eventlet/hubs/hub.py", line 313, in switch
2022-01-12 16:27:06.063 7 ERROR nova.compute.manager [instance: c303e65f-f34c-45ab-bc94-885088537c4c] return self.greenlet.switch()
2022-01-12 16:27:06.063 7 ERROR nova.compute.manager [instance: c303e65f-f34c-45ab-bc94-885088537c4c] eventlet.timeout.Timeout: 300 seconds
2022-01-12 16:27:06.063 7 ERROR nova.compute.manager [instance: c303e65f-f34c-45ab-bc94-885088537c4c]
2022-01-12 16:27:06.063 7 ERROR nova.compute.manager [instance: c303e65f-f34c-45ab-bc94-885088537c4c] During handling of the above exception, another exception occurred:
2022-01-12 16:27:06.063 7 ERROR nova.compute.manager [instance: c303e65f-f34c-45ab-bc94-885088537c4c]
2022-01-12 16:27:06.063 7 ERROR nova.compute.manager [instance: c303e65f-f34c-45ab-bc94-885088537c4c] Traceback (most recent call last):
2022-01-12 16:27:06.063 7 ERROR nova.compute.manager [instance: c303e65f-f34c-45ab-bc94-885088537c4c] File "/var/lib/kolla/venv/lib/python3.6/site-packages/nova/compute/manager.py", line 2413, in _build_and_run_instance
2022-01-12 16:27:06.063 7 ERROR nova.compute.manager [instance: c303e65f-f34c-45ab-bc94-885088537c4c] accel_info=accel_info)
2022-01-12 16:27:06.063 7 ERROR nova.compute.manager [instance: c303e65f-f34c-45ab-bc94-885088537c4c] File "/var/lib/kolla/venv/lib/python3.6/site-packages/nova/virt/libvirt/driver.py", line 4198, in spawn
2022-01-12 16:27:06.063 7 ERROR nova.compute.manager [instance: c303e65f-f34c-45ab-bc94-885088537c4c] cleanup_instance_disks=created_disks)
2022-01-12 16:27:06.063 7 ERROR nova.compute.manager [instance: c303e65f-f34c-45ab-bc94-885088537c4c] File "/var/lib/kolla/venv/lib/python3.6/site-packages/nova/virt/libvirt/driver.py", line 7256, in _create_guest_with_network
2022-01-12 16:27:06.063 7 ERROR nova.compute.manager [instance: c303e65f-f34c-45ab-bc94-885088537c4c] raise exception.VirtualInterfaceCreateException()
2022-01-12 16:27:06.063 7 ERROR nova.compute.manager [instance: c303e65f-f34c-45ab-bc94-885088537c4c] nova.exception.VirtualInterfaceCreateException: Virtual Interface creation failed
2022-01-12 16:27:06.063 7 ERROR nova.compute.manager [instance: c303e65f-f34c-45ab-bc94-885088537c4c]

Probably something goes wrong on the Neutron side which makes the revert impossible. Could you please check the Neutron logs to see what could happen ?
Either way, doesn't look a specific Nova issue but I'm open to other thoughts.

Put the bug status back to New once you reply.