openstack/charm-specs
Code Issues Proposed changes
95f6a394ba
charm-specs/specs/stein/approved/lxd-to-nova-lxd-rename.rst
Camille Rodriguez 891a56d519 Avoid pollution and false positives with tox.ini 
- Added 'Alternatives' section in lxd-to-nova-lxd-rename.rst too avoid
pep8 error, and fixed other pep8 mistakes
- changing testenv to python3
- removing sitepackages in tox.ini to avoid test env pollution
- skip_missing_interpreters in tox.ini set to False to avoid false
positives by skipping missing interpreters.

Change-Id: Id746fff4bfe7b0dd3ccb2803793f78a194d81355
2019-08-29 09:52:21 -04:00

4.2 KiB
Raw Blame History

Renaming the lxd charm to nova-lxd

The initial 'push' to rename the charm to nova-lxd is:

  1. The name nova-lxd better reflects that the charm is used with nova. It is confusing for users that the (currently named) lxd charm must be used with the nova-compute charm, and can't be used in a different environment.
  2. It releases the name lxd for use as a general purpose charm for LXD, that could be created to allow clusters of LXD machines to configured with Juju and MaaS.

Problem Description

The name of the charm as lxd is causing some confusion in the community as potential users are unaware that it is an OpenStack specific charm for nova as a subordinate. Therefore, changing the name of the charm to nova-lxd will help mitigate this confusion.

Proposed Change

  • The lxd charm will be copied to nova-lxd with all of its existing functionality.
  • The existing lxd charm will be converted to a no-op charm with a blocked status message indicating that the user should use the nova-lxd charm instead. The lxd charm will then be removed entirely after another cycle.
  • Making the existing lxd charm a no-op also has the advantage that existing installations will be unable to upgrade to the newer 'no-op' lxd charm as the relations will not match, thus forcing the operator to investigate as well as not breaking existing installations.

The charm name will be switched with the juju upgrade-charm lxd --switch=nova-lxd method of changing a charm and this will be tested during upgrades.

Alternatives

No alternatives suggested.

Implementation

Assignee(s)

Primary assignee: ajkavanagh

Gerrit Topic

Use Gerrit topic "nova-lxd-charm" for all patches related to this spec.

git-review -t nova-lxd-charm

Work Items

There are the following, logically separate, pieces of work in this specification:

  1. Turning the existing lxd charm into a 'no-op' charm with a blocked status message. For the avoidance of doubt, Juju will refuse to upgrade an existing lxd charm to this charm. The purpose of the blocked message is for new deployments where the deployment bundle should use nova-lxd, but instead refers to the old name. In this case, the charm will not do anything as a subordinate except to show the blocked message.
  2. Creating the new nova-lxd charm by copying the existing lxd charm repository over.
  3. Create project for nova-lxd charm on OpenStack on gerrit
  4. Create launchpad project for nova-lxd charm

Repositories

New git repository: openstack/charm-nova-lxd

This will be created as part of creating the charm-nova-lxd project on openstack.

Documentation

  1. Add notes the Charm Deployment Guide about the new charm.
  2. Add notes to the upgrades section to discuss how to upgrade from lxd to nova-lxd, what issues may occur, and how to recover the situation.

Security

None noted.

Testing

As the charm is just being renamed, there should be no issues with unit and functional tests. They will not change as part of the specification.

However, the various bundles that use the lxd charm will need to be updated to refer to a nova-lxd charm for the 19.04 release. These are contained in:

  • github: openstack-charmers/openstack-bundles - openstack-lxd
  • github: openstack-charmers/openstack-charm-testing
    • README-lxd.md
    • README-multihypervisor.md
    • bundles/lxd/*
    • bundles/multi-hypervisor/*

Testing on a MaaS will be necessary for the modified openstack-lxd bundles.

Dependencies

None noted.