[openstack-dev] [Nova][Glance]Glance v2 api support in Nova

Sean Dague sean at dague.net
Fri Feb 19 11:45:41 UTC 2016

On 02/15/2016 06:00 PM, Flavio Percoco wrote:
> On 12/02/16 18:24 +0300, Mikhail Fedosin wrote:
>> Hello!
>> In late December I wrote several messages about glance v2 support in
>> Nova and
>> Nova's xen plugin. Many things have been done after that and now I'm
>> happy to
>> announce that there we have a set of commits that makes Nova fully v2
>> compatible (xen plugin works too)!
>> Here's the link to the top commit
>> https://review.openstack.org/#/c/259097/
>> Here's the link to approved spec for Mitaka https://github.com/openstack/
>> nova-specs/blob/master/specs/mitaka/approved/use-glance-v2-api.rst
>> I think it'll be a big step for OpenStack, because api v2 is much more
>> stable
>> and RESTful than v1.  We would very much like to deprecate v1 at some
>> point. v2
>> is 'Current' since Juno, and after that there we've had a lot of
>> attempts to
>> adopt it in Nova, and every time it was postponed to next release cycle.
>> Unfortunately, it may not happen this time - this work was marked as
>> 'non-priority' when the related patches had been done. I think it's a big
>> omission, because this work is essential for all OpenStack, and it
>> will be a
>> shame if we won't be able to land it in Mitaka.
>> As far as I know, Feature Freeze will be announced on March, 3rd, and
>> we still
>> have enough time and people to test it before. All patches are split
>> into small
>> commits (100 LOC max), so they should be relatively easy to review.
>> I wonder if Nova community members may change their decision and
>> unblock this
>> patches? Thanks in advance!
> A couple of weeks ago, I had a chat with Sean Dague and John Garbutt and we
> agreed that it was probably better to wait until Newton. After that
> chat, we
> held a Glance virtual mid-cycle where Mikhail mentioned that he would
> rather
> sprint on getting Nova on v2 than waiting for Newton. The terms and code
> Mikhail
> worked on aligns with what has been discussed throughout the cycle in
> numerous
> chats, patch sets, etc.
> After all the effort that has been put on this (including getting a py24
> environment ready to test the xenplugin) it'd be a real shame to have
> this work
> pushed to Newton. The Glance team *needs* to be able to deprecate v1 and
> the
> team has been working on this ever since Kilo, when this effort of
> moving Nova
> to v2 started.
> I believe it has to be an OpenStack priority to make this happen or, at
> the very
> least, a cross-project effort that involves all services relying on
> Glance. Nova
> is the last service in the list, AFAICT, and the Glance team has been very
> active on this front. This is not to imply the Nova team hasn't help, in
> fact,
> there's been lots of support/feedback from the nova team during Mitaka.
> It is
> because of that that I believe we should grant this patches an exception
> and let
> them in.
> Part of the feedback the Nova team has provided is that some of that
> code that
> has been proposed should live in glanceclient. The Glance team is ready
> to react
> and merge that code, release glanceclient, and get Nova on v2.

Right, I think this was the crux of the problem. It took a while to get
consensus on that point, and now we're deep into the priority part of
the Nova cycle, and the runway is gone. I'm happy to help review early
during the Newton cycle.

I also think as prep work for that we should probably get either glance
folks or citrix folks to enhance the testing around the xenserver /
glance paths in Nova. That will make reviews go faster in Newton because
we can be a lot more sure that patches aren't breaking anything.


Sean Dague

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