Provide a way to use the charm without Swift service deployed

[Nobuto Murata]

As per the following commit:
https://opendev.org/openstack/charm-glance-simplestreams-sync/commit/25a0877228efedee21ffb2475326d2983a49690a

use_swift=false option will be removed sooner or later and having Swift with an OpenStack deployment will be the only option. However, having product-streams inside the OpenStack deployment is optional since g-s-s still saves the actual image content in Glance backed by Ceph by default, not Swift. It would be nice to have a way to disable the creation of the Keystone endpoint since having a bare g-s-s just to synchronize images to Glance is still useful.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.opendev.org/c/openstack/charm-glance-simplestreams-sync/+/799381

[Nobuto Murata (nobuto)]

Another way of solving this is just not to install apache2 or configure anything when use_swift is false.

[OpenStack Infra (hudson-openstack)]

Change abandoned by "Nobuto Murata <email address hidden>" on branch: master
Review: https://review.opendev.org/c/openstack/charm-glance-simplestreams-sync/+/799381
Reason: The following one would solve the same issue in a simpler and desirable way.
https://review.opendev.org/c/openstack/charm-glance-simplestreams-sync/+/806579

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/c/openstack/charm-glance-simplestreams-sync/+/806579
Committed: https://opendev.org/openstack/charm-glance-simplestreams-sync/commit/d1f8c4ba4cec4324ef9edc91c357672349176dfc
Submitter: "Zuul (22348)"
Branch: master

commit d1f8c4ba4cec4324ef9edc91c357672349176dfc
Author: Dmitrii Shcherbakov <email address hidden>
Date: Mon Aug 30 16:17:32 2021 +0300

    Remove local apache2 install, rework use_swift

    The functionality of use_swift where a local apache2 instance was set up
    for metadata was deprecated for removal and this change actually removes
    this. However, the option itself can still be used as an indicator
    whether Swift is intended to be used for simplestreams metadata or not.
    If the usage is explicitly requested, the charm but Swift endpoints are
    not yet present, the charm will now will set the unit state to
    maintenance in addition to local logging that was done previously.

    Swift presence checking is now endpoint-based instead of being
    service-based (no use for the case where endpoints are not set up while
    the service is in the catalog).

    The lack of swift presence is also ignored for the purposes of
    generating proxy setting context - if the endpoint is not there there is
    not point in trying to generate NO_PROXY rules for it.

    This change also makes test bundles use ceph as a storage medium for
    glance since out of space errors were encountered during testing as the
    glance unit was running out of space for image storage.

    Closes-Bug: #1942047
    Closes-Bug: #1934563
    Closes-Bug: #1938069

    Change-Id: I6519b1449806ad19ee4545501bc4631c9f8e535f

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: stable/21.04
Review: https://review.opendev.org/c/openstack/charm-glance-simplestreams-sync/+/810811

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/c/openstack/charm-glance-simplestreams-sync/+/810811
Committed: https://opendev.org/openstack/charm-glance-simplestreams-sync/commit/87d8f0b30909702c67799c27f985d6b325d4fc0e
Submitter: "Zuul (22348)"
Branch: stable/21.04

commit 87d8f0b30909702c67799c27f985d6b325d4fc0e
Author: Dmitrii Shcherbakov <email address hidden>
Date: Mon Aug 30 16:17:32 2021 +0300

    Remove local apache2 install, rework use_swift

    The functionality of use_swift where a local apache2 instance was set up
    for metadata was deprecated for removal and this change actually removes
    this. However, the option itself can still be used as an indicator
    whether Swift is intended to be used for simplestreams metadata or not.
    If the usage is explicitly requested, the charm but Swift endpoints are
    not yet present, the charm will now will set the unit state to
    maintenance in addition to local logging that was done previously.

    Swift presence checking is now endpoint-based instead of being
    service-based (no use for the case where endpoints are not set up while
    the service is in the catalog).

    The lack of swift presence is also ignored for the purposes of
    generating proxy setting context - if the endpoint is not there there is
    not point in trying to generate NO_PROXY rules for it.

    This change also makes test bundles use ceph as a storage medium for
    glance since out of space errors were encountered during testing as the
    glance unit was running out of space for image storage.

    Closes-Bug: #1942047
    Closes-Bug: #1934563
    Closes-Bug: #1938069

    Change-Id: I6519b1449806ad19ee4545501bc4631c9f8e535f
    (cherry picked from commit d1f8c4ba4cec4324ef9edc91c357672349176dfc)