[openstack-dev] Improvement of Cinder API wrt https://bugs.launchpad.net/nova/+bug/1213953

Caitlin Bestler caitlin.bestler at nexenta.com
Tue Nov 12 21:02:13 UTC 2013

On 11/12/2013 10:42 AM, John Griffith wrote:

> Sorry, but I'm not seeing where you're going with this in relation to
> the question being asked?  The question is how to deal with creating a
> new bootable volume from nova boot command and be able to tell whether
> it's timed out, or errored while waiting for creation.  Not sure I'm
> following your solution here, in an ideal scenario yes, if the backend
> has a volume with the image already available they could utilize
> things like cloning or snapshot features but that's a pretty
> significant pre-req and I'm not sure how it relates to the general
> problem that's being discussed.

I see the issue being discussed as "how to effectively deploy from 
Glance to Cinder boot images". Viewing the issue as being the lack
of time-out or error messages on a path that was already too long
is limiting.

Yes, if you are going to deploy from Glance in that fashion then
time-out and error messages are undoubtedly needed. The more important
issue is that the this is instrumenting a poor method of deploying
from Glance.

There are indeed many steps in the more complete solution:
* Check-out from glance for target environment.
* Create snapshot
* Replicate snapshot to desired target(s).
* When bootable image is needed:
* 	Clone volume from snapshot.
*	Boot from volume

But all of those steps can be orchestrated behind a taskflow, which
can also deal with Volume Drivers that do not efficiently snapshot.

My point is that taking the shackles off of snapshots and making them
first class Cinder objects is a solution to *many* problems - booting
based upon a Glance master is just one of them.

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