Comment 5 for bug 1659062

Reviewed: https://review.openstack.org/603844
Committed: https://git.openstack.org/cgit/openstack/nova/commit/?id=542635034882e1b6897e1935f09d6feb6e77d1ce
Submitter: Zuul
Branch: master

commit 542635034882e1b6897e1935f09d6feb6e77d1ce
Author: Jack Ding <email address hidden>
Date: Wed Sep 19 11:54:44 2018 -0400

    Correct instance port binding for rebuilds

    The following 2 scenarios could result in an instance with incorrect
    port binding and cause subsequent rebuilds to fail.

    If an evacuation of an instance fails part way through, after the point
    where we reassign the port binding to the new host but before we change
    the instance host, we end up with the ports assigned to the wrong host.
    This change adds a check to determine if there's any port binding host
    mismatches and if so trigger setup of instance network.

    During recovery of failed hosts, neutron could get overwhelmed and lose
    messages, for example when active controller was powered-off in the
    middle of instance evacuations. In this case the vif_type was set to
    'binding_failed' or 'unbound'. We subsequently hit "Unsupported VIF
    type" exception during instance hard_reboot or rebuild, leaving the
    instance unrecoverable.

    This commit changes _heal_instance_info_cache periodic task to update
    port binding if evacuation fails due to above errors so that the
    instance can be recovered later.

    Closes-Bug: #1659062
    Related-Bug: #1784579

    Co-Authored-By: Gerry Kopec <email address hidden>
    Co-Authored-By: Jim Gauld <email address hidden>
    Change-Id: I75fd15ac2a29e420c09499f2c41d11259ca811ae
    Signed-off-by: Jack Ding <email address hidden>