Can't update MAC address for direct-physical ports

[Ludovic Beliveau]

This bug also affect nova and is described in details there:
https://bugs.launchpad.net/nova/+bug/1617429

Nova needs to be fixed in order to update the MAC address of the neutron ports of type direct-physical.

A fix has been proposed for the nova issue. However, sending a MAC address update to neutron-server reports the following error:

Unable to complete operation on port d19c4cef-7415-4113-ba92-2495f00384d2, port is already bound, port type: hostdev_physical, old_mac 90:e2:ba:48:27:ed, new_mac 00:1e:67:51:36:71.

Description:
============

Booting a guest with a neutron port of type 'direct-physical' will cause nova to allocate a PCI passthrough device for the port. The MAC address of the PCI passthrough device in the guest is not a virtual MAC address (fa:16:...) but the MAC address of the physical device since the full device is allocated to the guest (compared to SR-IOV where a virtual MAC address is arbitrarily chosen for the port).

When resizing the guest (to another flavor), nova will allocate a new PCI device for the guest. After the resize, the guest will be bound to another PCI device which has a different MAC address. However the MAC address on the neutron port is not updated, causing DHCP to not work because the MAC address is unknown.

The same issue can be observed when migrating a guest to another host.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/361468

[OpenStack Infra (hudson-openstack)]

Change abandoned by Armando Migliaccio (<email address hidden>) on branch: master
Review: https://review.openstack.org/361468
Reason: This review is > 4 weeks without comment, and failed Jenkins the last time it was checked. We are abandoning this for now. Feel free to reactivate the review by pressing the restore button and leaving a 'recheck' comment to get fresh test results.

[Brian Haley (brian-haley)]

This bug was fixed in a different way in https://review.opendev.org/#/c/661298/ - I'll mark as a duplicate of the bug mentioned there.