Comment 39 for bug 1414559

Reviewed: https://review.openstack.org/559032
Committed: https://git.openstack.org/cgit/openstack/nova/commit/?id=ff747792b8f5aefe1bebb01bdf49dacc01353348
Submitter: Zuul
Branch: stable/pike

commit ff747792b8f5aefe1bebb01bdf49dacc01353348
Author: Sahid Orentino Ferdjaoui <email address hidden>
Date: Thu Aug 24 09:13:09 2017 -0400

    libvirt: slow live-migration to ensure network is ready

    In Neutron, commit b7c303ee0a16a05c1fdb476dc7f4c7ca623a3f58 introduced
    events sent during a live migration when the VIFs are plugged on
    destination node.

    The Linux bridge agent mechanism driver is detecting new networks on
    the destination host only when the TAP devices are created, and these
    tap devices are only created when libvirt starts the migration. As a
    result, we must actually start the migration and then slow it as we
    wait for the neutron events.

    This change ensures we wait for these events.

    Depends-On: Icb039ae2d465e3822ab07ae4f9bc405c1362afba

    Conflicts:
            nova/tests/unit/virt/libvirt/test_driver.py
            nova/virt/libvirt/driver.py

    NOTE(lyarwood): The driver.py conflict is due to additional QEMU and
    LIBVIRT version constants being present in Queens. The test_driver.py
    conflict being the result of our need to assert byte strings in Pike as
    also seen by I9b545ca8aa6dd7b41ddea2d333190c9fbed19bc1 and resolved by
    I85cd9a903fba310b5ae7bedeed118ca4ea98dff6 in Queens.

    Closes-Bug: #1414559
    Signed-off-by: Sahid Orentino Ferdjaoui <email address hidden>
    Change-Id: I407034374fe17c4795762aa32575ba72d3a46fe8
    (cherry picked from commit 8e6d5d404cf49e5b68b43c62e7f6d7db2771a1f4)
    (cherry picked from commit 224ac25cb1cca60e051cf4dc821eb549e8b36ff2)