Description

Images can be created from running volume-backed nova instances, analogous to an EBS-backed AMI in EC2.

The image data is not stored in glance, rather it is cloned from a snapshot of the backing volume.

Setup

Run previous test case.

Create an image from the running instance:

$> nova image-create volume_backed volume_backed_image
$> SNAPSHOT_IMAGE_ID=$(glance image-list | awk '/volume_backed_image/ {print $2}')

Boot the image created from the running volume-backed instance:

$> nova boot --flavor 1 --image $SNAPSHOT_IMAGE_ID from_volume_backed

You should be able able to ssh into the second volume-backed instance.

Note that an additional snapshot now exists to back the image:

$> cinder snapshot-list

Note the properties on the new image:

$> glance image-show $SNAPSHOT_IMAGE_ID

and the lack of image data (as that is taken from the volume snapshot).

Note also that the EC2 API reports the image as being EBS-backed as opposed to instance-store:

$> euca-describe-images

Also note for each of the two volume-backed instances you've fired up, there is a volume cloned from the corresponding snapshot:

$> cinder list