[openstack-dev] [heat] [glance] Heater Proposal
Edmund Troche
edmund.troche at us.ibm.com
Fri Dec 6 23:12:21 UTC 2013
I thought about that, i.e. first step in implementation just adding
templates, but like you said, you might end up duplicating 5 of the 7
tables in the Glance database, for every new "asset type" (image, template,
etc). Then you would do a similar thing for the endpoints. So, I'm not sure
what's a better way to approach this. For all I know, doing a
"s/image/asset/g" for *.py,, adding attribute images.type, and a little
more refactoring, might get us 80% of the asset management functionality
that we would need initially ;-) Not knowing the Glance code base I'm only
going by the surface footprint, so I'll leave it to the experts to comment
on what would be a good approach to take Glance to the next level.
Edmund Troche
From: Randall Burt <randall.burt at RACKSPACE.COM>
To: "OpenStack Development Mailing List (not for usage questions)"
<openstack-dev at lists.openstack.org>,
Date: 12/06/2013 04:47 PM
Subject: Re: [openstack-dev] [heat] [glance] Heater Proposal
I too have warmed to this idea but wonder about the actual implementation
around it. While I like where Edmund is going with this, I wonder if it
wouldn't be valuable in the short-to-mid-term (I/J) to just add /templates
to Glance (/assemblies, /applications, etc) along side /images. Initially,
we could have separate endpoints and data structures for these different
asset types, refactoring the easy bits along the way and leveraging the
existing data storage and caching bits, but leaving more disruptive changes
alone. That can get the functionality going, prove some concepts, and allow
all of the interested parties to better plan a more general v3 api.
On Dec 6, 2013, at 4:23 PM, Edmund Troche <edmund.troche at us.ibm.com>
wrote:
I agree with what seems to also be the general consensus, that Glance
can "become" Heater+Glance (the service that manages images in OS
today). Clearly, if someone looks at the Glance DB schema, APIs and
service type (as returned by keystone service-list), all of the
terminology is about images, so we would need to more formally define
what are the characteristics or "image", "template", maybe
"assembly", "components" etc and find what is a good generalization.
When looking at the attributes for "image" (image table), I can see
where there are a few that would be generic enough to apply to
"image", "template" etc, so those could be taken to be the base set
of attributes, and then based on the "type" (image, template, etc) we
could then have attributes that are type-specific (maybe by
leveraging what is today "image_properties").
As I read through the discussion, the one thing that came to mind is
"asset management". I can see where if someone bothers to create an
image, or a template, then it is for a good reason, and that perhaps
you'd like to maintain it as an IT asset. Along those lines, it
occurred to me that maybe what we need is to make Glance some sort of
asset management service that can be leveraged by Service Catalogs,
Nova, etc. Instead of storing "images" and "templates" we store
assets of one kind or another, with artifacts (like files, image
content, etc), and associated metadata. There is some work we could
borrow from, conceptually at least, from OSLC's Asset Management
specification:
http://open-services.net/wiki/asset-management/OSLC-Asset-Management-2.0-Specification/
. Looking at this spec, it probably has more than we need, but
there's plenty we could borrow from it.
Edmund Troche
<graycol.gif>Georgy Okrokvertskhov ---12/06/2013 01:34:13 PM---As a
Murano team we will be happy to contribute to Glance. Our Murano
metadata repository is a stand
From: Georgy Okrokvertskhov <gokrokvertskhov at mirantis.com>
To: "OpenStack Development Mailing List (not for usage questions)" <
openstack-dev at lists.openstack.org>,
Date: 12/06/2013 01:34 PM
Subject: Re: [openstack-dev] [heat] [glance] Heater Proposal
As a Murano team we will be happy to contribute to Glance. Our Murano
metadata repository is a standalone component (with its own git
repository)which is not tightly coupled with Murano itself. We can
easily add our functionality to Glance as a new component\subproject.
Thanks
Georgy
On Fri, Dec 6, 2013 at 11:11 AM, Vishvananda Ishaya <
vishvananda at gmail.com> wrote:
On Dec 6, 2013, at 10:38 AM, Clint Byrum <clint at fewbar.com>
wrote:
> 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.
+1
Vish
>
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--
Georgy Okrokvertskhov
Technical Program Manager,
Cloud and Infrastructure Services,
Mirantis
http://www.mirantis.com
Tel. +1 650 963 9828
Mob. +1 650 996 3284_______________________________________________
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