Manila Charm does not support multiple share backends

[Vern Hart]

In my current deployment, the customer wants to use netapp as a share backend by default but wants the option to use cephfs as a backend.

I deployed manila and manila-ganesha and related them together and the manila shares were working properly.

I then added manila-netapp and related it to manila. The manila-netapp subordinate charm deployed without issue but the manila charm became blocked saying there default-share-backed is not a configured backend. After a quick investigation, I see that the cephfs (ganesha) backend was no longer defined in manila.conf.

Expected result: Both backend should be defined in manila.conf.

I removed the manila-netapp/manila relation and manila was then blocked for "No share backends configured." As a test, I removed the manila-ganesha/manila relation and re-added it. For a moment, manila said it was Ready but then shortly returned to the "No share backends" block.

The manila charm uses get_adapter('manila-plugin.available') *or* get_adapter('remote-manila-plugin.available') which will definitely only return the adapter for one plugin between manila-plugin and remote-manila-plugin. But even if the two relations are both using manila-plugin, the get_adapter function returns only one relation.

There doesn't seem to be an easy way to revamp this structure to allow multiple backends.

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/c/openstack/charm-manila/+/867047
Committed: https://opendev.org/openstack/charm-manila/commit/eb6437174a63130b21f2404876ac4e840e9e9314
Submitter: "Zuul (22348)"
Branch: master

commit eb6437174a63130b21f2404876ac4e840e9e9314
Author: Chris MacNaughton <email address hidden>
Date: Thu Dec 8 14:00:05 2022 -0500

    Ensure that local and remote plugins can be used concurrently

    To ensure that it works, this change also updates the functional
    test bundles to include manila-netapp and manila-netapp-dhss in
    the gate.

    This change also picks up a drive-by change to fix a tox
    dependency change.

    Closes-Bug: #1996962
    Change-Id: Ic5a2b2fcced129220b70a16539b41813b0feb3be

[Camille Rodriguez (camille.rodriguez)]

Hi, is there an update on when this fix will be released ?

[Alex Kavanagh (ajkavanagh)]

Hi Camille

At present, this is (as you've correctly noted), only released to latest/edge (from the main development branch). It will be released as part of 2023.1 (antelope) which is imminent. However, there aren't any plans (yet) to backport this to any other versions.

Please could you indicate the earliest OpenStack version that you would absolutely need for this to work on?

Thanks!

[Camille Rodriguez (camille.rodriguez)]

Hi Alex, we would it need backported to the latest LTS openstack, jammy/yoga

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: stable/zed
Review: https://review.opendev.org/c/openstack/charm-manila/+/884382

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: stable/yoga
Review: https://review.opendev.org/c/openstack/charm-manila/+/884383

[Alex Kavanagh (ajkavanagh)]

Hi Camille, ok: that's now been cherry-picked back to jammy-yoga, so hopefully they will pass and can be landed.

[Przemyslaw Hausman (phausman)]

Hi Alex, we would also need this fix backported to focal-yoga. It is for the customer deployment that is about to start. Can we please have it backported in the coming weeks?

[Alex Kavanagh (ajkavanagh)]

Hi Przemyslaw; when this is successfully backported to the yoga channel it will also support focal. However, the two cherry picks to zed and yoga are failing in gate, so it looks like this new feature in the charm isn't clean/being easy to backport. Thus, I can't say it would be ready in a few weeks.

[Narinder Gupta (narindergupta)]

Looks like those changes have integration issues when we deploy and ganesha nd netapp. manila-netapp is subbordinate charm while ganesha needs a seperate unit. Also ganesha configs are not in seperate section of manila.conf it is part of defaults and breals manila-share service in manila unit.

https://bugs.launchpad.net/charm-manila/+bug/2032480

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/c/openstack/charm-manila/+/884382
Committed: https://opendev.org/openstack/charm-manila/commit/85ee6e38ba1507bea5e4143ac7d553f6ddf159b7
Submitter: "Zuul (22348)"
Branch: stable/zed

commit 85ee6e38ba1507bea5e4143ac7d553f6ddf159b7
Author: Chris MacNaughton <email address hidden>
Date: Thu Dec 8 14:00:05 2022 -0500

    Ensure that local and remote plugins can be used concurrently

    To ensure that it works, this change also updates the functional
    test bundles to include manila-netapp and manila-netapp-dhss in
    the gate.

    This change also picks up a drive-by change to fix a tox
    dependency change.

    NOTE: update src/tests-requirements.txt before merging; has test delayed
    to allow discovery as to why the share handle goes stale.

    (cherry picked from commit eb6437174a63130b21f2404876ac4e840e9e9314)

    Closes-Bug: #1996962
    Change-Id: Ic5a2b2fcced129220b70a16539b41813b0feb3be

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/c/openstack/charm-manila/+/884383
Committed: https://opendev.org/openstack/charm-manila/commit/5c406b1d5e1d39c1a671b498135a69df9ac743cf
Submitter: "Zuul (22348)"
Branch: stable/yoga

commit 5c406b1d5e1d39c1a671b498135a69df9ac743cf
Author: Chris MacNaughton <email address hidden>
Date: Thu Dec 8 14:00:05 2022 -0500

    Ensure that local and remote plugins can be used concurrently

    To ensure that it works, this change also updates the functional
    test bundles to include manila-netapp and manila-netapp-dhss in
    the gate.

    (note modified as bundles are different, and to only apply to jammy-yoga
    from an integration test perspective).

    Closes-Bug: #1996962
    Change-Id: Ic5a2b2fcced129220b70a16539b41813b0feb3be
    (cherry picked from commit eb6437174a63130b21f2404876ac4e840e9e9314)