Comment 10 for bug 1752540

Reviewed: https://review.openstack.org/552900
Committed: https://git.openstack.org/cgit/openstack/openstack-ansible-os_nova/commit/?id=707398789403293aaedc1d78ddc4a164611366c7
Submitter: Zuul
Branch: stable/ocata

commit 707398789403293aaedc1d78ddc4a164611366c7
Author: Jimmy McCrory <email address hidden>
Date: Thu Feb 22 08:55:06 2018 -0800

    Rearrange cell mapping tasks

    Existing instances can be mapped to a newly created cell immediately
    after the cell is created and by the same conductor host that created
    the cell.

    After a new compute host is built, it will need to mapped to a cell
    through the 'discover_hosts' command of nova-manage. This command will
    still need to be run against a host that has direct database access, but
    the command is able to handle mapping of all compute hosts that do not
    currently belong to the cell so it only needs to be run once per play.

    There can be a short delay in the time between a compute service
    starting and becoming available to be discovered and mapped but, for
    most deployments, compute host discovery will be handled automatically
    as a periodic task.

    Conflicts:
    >------tasks/main.yml

    Change-Id: I4f7328e1aff79eb94f278999b97fbad8f44c6a3e
    Closes-Bug: 1749037
    Related-Bug: 1729661
    Related-Bug: 1752540
    (cherry picked from commit 6321cf90304023c20dc6abb87e2fa20107b7051d)