Excerpts from Jay Pipes's message of 2013-12-05 21:32:54 -0800: > On 12/05/2013 04:25 PM, Clint Byrum wrote: > > Excerpts from Andrew Plunk's message of 2013-12-05 12:42:49 -0800: > >>> Excerpts from Randall Burt's message of 2013-12-05 09:05:44 -0800: > >>>> On Dec 5, 2013, at 10:10 AM, Clint Byrum <clint at fewbar.com> > >>>> wrote: > >>>> > >>>>> Excerpts from Monty Taylor's message of 2013-12-04 17:54:45 -0800: > >>>>>> Why not just use glance? > >>>>>> > >>>>> > >>>>> I've asked that question a few times, and I think I can collate the > >>>>> responses I've received below. I think enhancing glance to do these > >>>>> things is on the table: > >>>>> > >>>>> 1. Glance is for big blobs of data not tiny templates. > >>>>> 2. Versioning of a single resource is desired. > >>>>> 3. Tagging/classifying/listing/sorting > >>>>> 4. Glance is designed to expose the uploaded blobs to nova, not users > >>>>> > >>>>> My responses: > >>>>> > >>>>> 1: Irrelevant. Smaller things will fit in it just fine. > >>>> > >>>> Fitting is one thing, optimizations around particular assumptions about > >>>> the size of data and the frequency of reads/writes might be an issue, > >>>> but I admit to ignorance about those details in Glance. > >>>> > >>> > >>> Optimizations can be improved for various use cases. The design, however, > >>> has no assumptions that I know about that would invalidate storing blobs > >>> of yaml/json vs. blobs of kernel/qcow2/raw image. > >> > >> I think we are getting out into the weeds a little bit here. It is > >> important to think about these apis in terms of what they actually do, > >> before the decision of combining them or not can be made. > >> > >> I think of HeatR as a template storage service, it provides extra data and > >> operations on templates. HeatR should not care about how those templates > >> are stored. > >> Glance is an image storage service, it provides extra data and operations > >> on images (not blobs), and it happens to use swift as a backend. > >> > >> If HeatR and Glance were combined, it would result in taking two very > >> different types of data (template metadata vs image metadata) and mashing > >> them into one service. How would adding the complexity of HeatR benefit > >> Glance, when they are dealing with conceptually two very different types > >> of data? For instance, should a template ever care about the field > >> "minRam" that is stored with an image? Combining them adds a huge > >> development complexity with a very small operations payoff, and so > >> Openstack is already so operationally complex that HeatR as a separate > >> service would be knowledgeable. Only clients of Heat will ever care about > >> data and operations on templates, so I move that HeatR becomes it's own > >> service, or becomes part of Heat. > >> > > > > I spoke at length via G+ with Randall and Tim about this earlier today. > > I think I understand the impetus for all of this a little better now. > > > > Basically what I'm suggesting is that Glance is only narrow in scope > > because that was the only object that OpenStack needed a catalog for > > before now. > > > > However, the overlap between a catalog of images and a catalog of > > templates is quite comprehensive. The individual fields that matter to > > images are different than the ones that matter to templates, but that > > is a really minor detail isn't it? > > > > I would suggest that Glance be slightly expanded in scope to be an > > object catalog. Each object type can have its own set of fields that > > matter to it. > > > > This doesn't have to be a minor change to glance to still have many > > advantages over writing something from scratch and asking people to > > deploy another service that is 99% the same as Glance. > > My suggestion for long-term architecture would be to use Murano for > catalog/metadata information (for images/templates/whatever) and move > the block-streaming drivers into Cinder, and get rid of the Glance > project entirely. Murano would then become the catalog/registry of > objects in the OpenStack world, Cinder would be the thing that manages > and streams blocks of data or block devices, and Glance could go away. > Imagine it... OpenStack actually *reducing* the number of projects > instead of expanding! :) >
Have we not learned our lesson with Nova-Net/Neutron yet? Rewrites of existing functionality are painful. The Murano-concerned people have already stated they are starting over on that catalog. I suggest they start over by expanding Glance's catalog. If the block streaming bits of Glance need to move somewhere else, that sounds like a completely separate concern that distracts from this point. And to be clear, (I think I will just stop talking as I think I've made this point), my point is, we have a catalog, let's make it better. _______________________________________________ OpenStack-dev mailing list OpenStack-dev@lists.openstack.org http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev
