Independent boot from volume

[Vincent Hou]

So far when we try to boot from a volume, we need to specify both block-device-mapping and image-id. I suggest we get rid of the image-id in further development.
What we can do:
For image which has kernel and ramdisk, we can also copy them into two other volumes, set bootable to false for them and create the link with the bootable volume.

There are some attributes like disk format, container format, checksum, etc. We can also copy them into key-value pairs and save into volume_glance_metadata table, so even if the original image is deleted, all the information is still retained in volumes.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/34705

[Vincent Hou (houshengbo)]

This patch copies some more attributes into volume_glance_metadata, including size, disk_format, container_format,
checksum, min_disk and min_ram.

I have not implemented copying the kernal and ramdisk. Need more discussions about whether it is a good approach.

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/34705
Committed: http://github.com/openstack/cinder/commit/4ef5eabaeeb70d5090079819f4c2442742f43373
Submitter: Jenkins
Branch: master

commit 4ef5eabaeeb70d5090079819f4c2442742f43373
Author: Vincent Hou <email address hidden>
Date: Thu Jun 27 15:43:00 2013 +0800

    Save some more image attributes to volume_glance_metadata.

    Current issue: When copying an image to a volume, attributes like size, disk_format, container_format,
    checksum, min_disk and min_ram have not been copied so far. When booting a VM from a volume, we are
    not able to check these atrributes without giving the image id. Furthermore, if the original
    image is deleted, we will lose all the information.

    This patch saves these attributes into volume_glance_metadata. We can still check these attributes
    without giving the image id when booting a VM from a volume.

    Fixed Bug 1159824.

    Change-Id: I42ce676026d32be6e3f4bec6fd269908e2df0a8c