Comment 72 for bug 1815989

Reviewed: https://review.opendev.org/c/openstack/nova/+/797428
Committed: https://opendev.org/openstack/nova/commit/fa0fb2fe3d61de1cb871c48ee97053cf2fb5827a
Submitter: "Zuul (22348)"
Branch: master

commit fa0fb2fe3d61de1cb871c48ee97053cf2fb5827a
Author: Stephen Finucane <email address hidden>
Date: Tue Jun 22 11:37:22 2021 +0100

    libvirt: Always delegate OVS plug to os-vif

    In change I11fb5d3ada7f27b39c183157ea73c8b72b4e672e, we started
    delegating plugging of OVS ports to os-vif to work around a number of
    bugs. However, this was only introduced for live migration. Plugging is
    still handled by libvirt for spawn. This results in an odd situation,
    whereby an interface of type 'bridge' will be use when creating the
    instance initially, only for this to change to 'ethernet' on live
    migration. Resolve this by *always* delegating plugging to os-vif. This
    is achieved by consistently setting the 'delegate_create' attribute of
    'nova.network.model.VIF' to 'True', which will later get transformed to
    the 'create_port' attribute of the 'os_vif.objects.vif.VIFOpenVSwitch'
    object(s) created in 'nova.network.os_vif_util._nova_to_osvif_vif_ovs'
    and ultimately result in delegate port creation.

    Note that we don't need to worry about making the setting of
    'delegate_create' conditional on whether we're looking at an OVS port or
    not: this will be handled by '_nova_to_osvif_vif_ovs'. We also don't
    need to worry about unsetting this attribute before a live migration:
    the 'delegate_create' attribute is always overridden as part of
    'nova.objects.migrate_data.VIFMigrateData.get_dest_vif'.

    Change-Id: I014c5a81752f86c6b99d19d769c42f318e18e676
    Signed-off-by: Stephen Finucane <email address hidden>
    Related-Bug: #1734320
    Related-Bug: #1815989