Comment 1 for bug 1835002

Reviewed: https://review.opendev.org/668623
Committed: https://git.openstack.org/cgit/openstack/kolla-ansible/commit/?id=c38dd767118164aae37613d557ed23691813f617
Submitter: Zuul
Branch: master

commit c38dd767118164aae37613d557ed23691813f617
Author: Mark Goddard <email address hidden>
Date: Tue Jul 2 08:30:02 2019 +0100

    Wait for all compute services before cell discovery

    There is a race condition during nova deploy since we wait for at least
    one compute service to register itself before performing cells v2 host
    discovery. It's quite possible that other compute nodes will not yet
    have registered and will therefore not be discovered. This leaves them
    not mapped into a cell, and results in the following error if the
    scheduler picks one when booting an instance:

    Host 'xyz' is not mapped to any cell

    The problem has been exacerbated by merging a fix [1][2] for a nova race
    condition, which disabled the dynamic periodic discovery mechanism in
    the nova scheduler.

    This change fixes the issue by waiting for all expected compute services
    to register themselves before performing host discovery. This includes
    both virtualised compute services and bare metal compute services.

    [1] https://bugs.launchpad.net/kolla-ansible/+bug/1832987
    [2] https://review.opendev.org/665554

    Change-Id: I2915e2610e5c0b8d67412e7ec77f7575b8fe9921
    Closes-Bug: #1835002