Comment 6 for bug 1800511

Reviewed: https://review.openstack.org/614004
Committed: https://git.openstack.org/cgit/openstack/nova/commit/?id=29ee8011b4e1cf5371b1aa9c6c0f930eb49fe795
Submitter: Zuul
Branch: master

commit 29ee8011b4e1cf5371b1aa9c6c0f930eb49fe795
Author: Mohammed Naser <email address hidden>
Date: Mon Oct 29 19:18:26 2018 +0100

    Add tests for bug #1800511

    In Rocky, we started including the MTU for networks when vif_type
    is bridge or tap and libvirt >= 3.3.0, however this also meant
    that we started specifying the MTU when doing live migrations.

    It seems that the guest ABI changes when setting the MTU which
    means that live migrations will fail. This broke the live migration
    of any instance that was launched prior to upgrading to Rocky, as
    it was not loaded with the ABI having host_mtu specified.

    This is a passing (negative) test-case which will include a follow
    up patch that contains a fix and correcting tests.

    Related-Bug: #1800511
    Change-Id: Ia2fe50d727b1f83e808cb9dda3a55f853f048a3e