Booting from volume shouldn't require specifying an image

[Lorin Hochstein]

Booting from volume fails unless the user specifies an image:

$ nova boot --flavor 2 --key_name foo --block_device_mapping vda=13:::0 test

Generates the following error:

Invalid imageRef provided. (HTTP 400)

In general, booting from a volume should not require an image being specified.

See https://lists.launchpad.net/openstack/msg12369.html for mailing list discussion

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/16099
Committed: http://github.com/openstack/nova/commit/1d00dfcfbb9bdeff358503fefefc7e6e7b4903eb
Submitter: Jenkins
Branch: master

commit 1d00dfcfbb9bdeff358503fefefc7e6e7b4903eb
Author: Nikola Dipanov <email address hidden>
Date: Wed Nov 7 18:56:35 2012 +0100

    Boot from volume without image supplied

    This patch allows for booting instances without supplying an image if
    there is block device mapping supplied. It makes changes to nova API
    and
    compute services to handle requests that do not have any image
    supplied.

    Also it makes rescue and rebuild work with instances started from
    volume.

    Finally the patch introduces tests to make sure the system acts as
    expected, and in the process fixes and refactors some old tests to make
    them test for cases this new functionality can introduce.

    This patch is intended to be a proof of concept and a first step
    towards
    a more cleaner interface for booting from volumes, outlined in
    https://etherpad.openstack.org/grizzly-boot-from-volumes.

    This patch also introduces a slight modification of the nova API so I
    am flagging it with DocImpact. The change is that if the os-volumes
    extension is used ImageRef does not need to be supplied to the create
    server API call provided there is block_device_mapping provided.

    Also note that this is the first step towards introducing a 'volume'
    parameter
    for starting instances which will replace the somewhat unintuitive
    block_device_mapping (they will still be used but not for the boot
    device).

    This patch is coupled with I5ba9b0f35a5084aa91eca260f46cac83b8b6591e
    that provides changes to the nova client.

    Implements: blueprint improve-boot-from-volume
    Fixes bug #1008622

    Change-Id: I530760cfaa5eb0cae590c7383e0840c6b3f896b9