Open Stack

I have only played with Glance v2 locally on a devstack, so take what I write
with a graing of salt.

What's new in API v2?
---------------------

+ registry: You don't need to run glance-registry anymore. Unless you still
 support v1.

+ tags: Every image has a tag list metadata. A tag can be
 created/updated/deleted by an image owner. A tag can be read by any member of
 the image.

+ New membership mechanism: You can read about it here[1].

+ You can query the API for JSON schemas describing resources.


How well is it supported?
-------------------------

+ python-glanceclient: Supports API v2 through the cli flag  --os-image-api-version.

+ Cinder: Supports API v2 (for volume creation from images). You specify the API
 version in cinder.conf (glance_api_version option).

+ Nova: doesn't support v2. This mailing thread[2] gives a good overview of the
 situation.

+ Horizon: To the best of my knowledge, Horizon doesn't support v2 yet.


How well is it tested?
----------------------

I tried a few manual tests on a local devstack and it seemed to work. And the v2
seems to be pretty well covered in Tempest[3].


Can v1 and v2 coexist?
----------------------

From whatever little I've seen, both APIs can safely be activated alongside each
other. Some things to note:

+ v2 membership is not really taken into account if v1 is still activated.
+ you still need to run glance-registry if v1 is activated

Conclusion
----------
Again, I have just spent a couple of days playing with it on a devstack. I'm by
no means a reference on the subject of the API v2. I hope this will help you get
a better idea of where it stands today. And if anyone notices something I may
have missed or anything wrong in my summary, please do point it out so I can
correct it.

[1]: http://docs.openstack.org/api/openstack-image-service/2.0/content/image-sharing.html
[2]: http://lists.openstack.org/pipermail/openstack-dev/2014-February/026849.html
[3]: http://git.openstack.org/cgit/openstack/tempest/tree/tempest/api/image/v2

---
Joe H. Rahme
IRC: rahmu

On 14 Feb 2014, at 19:37, Pete Zaitcev <zaitcev at redhat.com> wrote:

> Hello:
> 
> does anyone happen to know, or have a detailed write-up, on the
> differences between so-called "Glance v1" and "Glance v2"?
> 
> In particular do we still need Glance Registry in Havana, or
> do we not? The best answer so far was to run the registry anyway,
> "just in case", which does not feel entirely satisfactory.
> Surely someone should know exactly what is going on in the API
> and have a good idea what the implications are for the users
> of Glance (API, CLI, and Nova (I include Horizon into API)).
> 
> Thanks,
> -- Pete
> 
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