Open Stack

At the last couple volumes meetings, there was some discussion of the
desired behaviors of nova's boot from volume functionality. There were
a few use cases discussed, but there are probably plenty we didn't
think of, so it would be useful to get input from a larger audience.

What use cases for boot from volume are people interested in, and
which should nova support?

Here are a few use cases:

   1) I use an existing instance to manually create a bootable volume
      containing an OS there is no image for (and I cannot create an
      image). I boot the new OS from the volume I created.

   2) I create a bunch of new instances that have no ephemeral disks,
      but are all based on the same image. The data from the image is
      copied to a new volume for each new instance.

   3) I have an instance that has no ephemeral disks, and stores
      everything in a volume. I take periodic snapshots of the
      volume. Later, my original instance becomes corrupted, and I want
      to restore from the last known good snapshot I took. I boot a new
      instance from a new volume created by cloning from the last
      good snapshot.