Comment 11 for bug 1764883

Reviewed: https://review.openstack.org/621200
Committed: https://git.openstack.org/cgit/openstack/nova/commit/?id=8bba879141d644b248d246cb2ed196068e20785c
Submitter: Zuul
Branch: stable/queens

commit 8bba879141d644b248d246cb2ed196068e20785c
Author: Lee Yarwood <email address hidden>
Date: Wed Apr 18 14:35:07 2018 +0100

    compute: Ensure pre-migrating instances are destroyed during init_host

    Previously _destroy_evacuated_instances would not remove instances
    associated with evacuation migration records in a pre-migrating state.
    This could lead to a race between the original source host and the new
    destination if the source returned early, calling init_instance during
    the evacuation process.

    This change now includes pre-migrating migration records when looking
    for active evacuations. Additionally the dict of evacuating instances is
    then returned to init_host and used to skip running init_instance
    against such instances ensuring no race occurs between the two computes.

    Closes-bug: #1764883
    Change-Id: I379678dfdb2609f12a572d4f99c8e9da4deab803
    (cherry picked from commit c4988cdabf311d29cf64af732091068cfabeedaa)