Running devstack without n-cpu or cinder enabled fails with 'vgs: command not found'

[Maru Newby]

A recent change adding support for ephemeral storage in Nova [1] added lvm init/configure/teardown to stack.sh without bracketing those calls with a check for whether n-cpu or cinder were enabled. Since those services need to be enabled to ensure the the supporting lvm packages are installed, a devstack run without those services will always fail when trying to invoke the missing commands.

1: https://review.openstack.org/#/c/132333

[Dean Troyer (dtroyer)]

The easy solution here is to add lvm to ENABLED_SERVICES and require it to be added when all services that need it are also present. This becomes a back-compat issue for an arguably larger set of users than the current situation.

We could also have the services that need lvm auto-enable it and solve the compat problem. We do not do this anywhere else and force the user to know exactly what services needs to be enabled for a given configuration.

The simplest solution is to just add the lvm prereqs to files/*/general.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/150518

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/150518
Committed: https://git.openstack.org/cgit/openstack-dev/devstack/commit/?id=c070a3dbb5c52fb9099bd6cec477ba3d0a75760a
Submitter: Jenkins
Branch: master

commit c070a3dbb5c52fb9099bd6cec477ba3d0a75760a
Author: Maru Newby <email address hidden>
Date: Tue Jan 27 17:44:44 2015 +0000

    Init default lvm volume group only if required

    A recent patch [1] added support for lvm ephemeral storage for nova,
    but at the cost of initializing a default lvm volume group even if it
    was not required. This change ensures that init of the default volume
    group is only performed when nova and/or cinder are configured to use
    lvm.

    1: https://review.openstack.org/#/c/132333

    Change-Id: I7634ca0ed0ffe1b13464e4d66744918f85149f2e
    Closes-Bug: #1414820