Open Stack

Hi,

A couple of years ago I created a Nova spec for the StorPool image
backend: https://review.openstack.org/#/c/137830/  There was some
discussion, but then our company could not immediately allocate the
resources to write the driver itself, so the spec languished and was
eventually abandoned.

Now that StorPool has a fully maintained Cinder driver and also a
fully maintained Nova volume attachment driver, both included in the
Queens release, and a Cinder third-party CI that runs all the tests
tagged with "volume", including some simple Nova tests, we'd like to
resurrect this spec and implement a Nova image backend, too.
Actually, it looks like due to customer demand we will write the
driver anyway and possibly maintain it outside the tree, but it would
be preferable (and, obviously, easier to catch up with wide-ranging
changes) to have it in.

Would there be any major opposition to adding a StorPool shared
storage image backend, so that our customers are not limited to
volume-backed instances?  Right now, creating a StorPool volume and
snapshot from a Glance image and then booting instances from that
snapshot works great, but in some cases, including some provisioning
and accounting systems on top of OpenStack, it would be preferable to
go the Nova way and let the hypervisor think that it has a local(ish)
image to work with, even though it's on shared storage anyway.  This
will go hand-in-hand with our planned Glance image driver, so that
creating a new instance from a Glance image would happen
instantaneously (create a StorPool volume from the StorPool snapshot
corresponding to the Glance image).

If this will help the decision, we do have plans for adding a
full-blown Nova third-party CI in the near future, so that both our
volume attachment driver, this driver, and our upcoming Glance image
driver will see some more testing.

Thanks in advance, and keep up the great work!

Best regards,
Peter