Allow per service configuration option to keep its systemd service unmanaged by tripleo-container-manager

[Bogdan Dobrelya]

It may be a good idea to create a facility to ignore unmanned systemd units for service containers. While keeping its corresponding containers under configuration, no service nor the container should be started/enabled in that mode.

That would allow users to manually disable some non-A/A or non H/A services in systemd, like cinder-volume with some 3rd party drivers, or just putting individual services into maintenance without touching the full node. And still having its containers configs/images up to date and be ready for enablement, once the time comes.

That could be a service-specific config option in containers config, like 'managed: true' by default, and controlled via a corresponding Heat parameter, e.g. CinderVolumeUnmanaged, or role based perhaps.

[Bogdan Dobrelya (bogdando)]

In systemd, the analogue is disabled state, which is honored and not enforced.
In pacemaker, the analogue is unmanaged state, which is also honored.
So making our systemd-based local container manager tooling honoring the unmanaged state seems natural to me.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: stable/ussuri
Review: https://review.opendev.org/745825

[Bogdan Dobrelya (bogdando)]

Ussuri how to test dev notes for the paunch part of this feature https://pastebin.com/geALHgPW

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: stable/train
Review: https://review.opendev.org/746032

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/745825
Committed: https://git.openstack.org/cgit/openstack/paunch/commit/?id=b995b0ade83b5be73e1c0bece5c2fd468c9fd113
Submitter: Zuul
Branch: stable/ussuri

commit b995b0ade83b5be73e1c0bece5c2fd468c9fd113
Author: Bogdan Dobrelya <email address hidden>
Date: Wed Aug 12 12:22:19 2020 +0200

    [USSURI-ONLY] Do not manage masked service units

    When a service unit for a containerized service has been
    manually masked, only ensure its container created, but not started.
    Also do not manage its service unit and timer.

    Partial-Bug: #1890789

    Change-Id: I571918f37f41f03cde390e94c9bacc873909f92f
    Signed-off-by: Bogdan Dobrelya <email address hidden>

[OpenStack Infra (hudson-openstack)]

Change abandoned by Bogdan Dobrelya (bogdando) (<email address hidden>) on branch: stable/train
Review: https://review.opendev.org/746032