Tech-debt: don't create specialized workers

[Joshua Harlow]

Creating very specialized threads makes re-usablity hard, it also makes testing hard (all logic to test is bundled inside that thread, and therefore can't be tested individually in a unit test) so kolla commands should strive to not do this.

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/321317
Committed: https://git.openstack.org/cgit/openstack/kolla/commit/?id=e78ae9bc618dff1ed38db1f5013d7f1735124790
Submitter: Jenkins
Branch: master

commit e78ae9bc618dff1ed38db1f5013d7f1735124790
Author: Joshua Harlow <email address hidden>
Date: Wed May 25 18:53:11 2016 -0700

    Use a task model and dumb workers

    Instead of having smart workers that need to know
    about the full logic of how they operate and what
    they will do which makes it hard to reuse parts of
    those workers switch the model so that workers are
    dumb and they just run tasks which themselves can
    request additional tasks to run when succesful.

    This makes it more consistent when tasks are to
    be retried and also makes it easier to know which
    task is running and when.

    Less specialized workers == good.

    Closes-Bug: #1586474

    Change-Id: Ie7b7303b8bf2a80b3e26b6d4ffc27787f8c794d6

[Doug Hellmann (doug-hellmann)]

This issue was fixed in the openstack/kolla 3.0.0.0b1 development milestone.