[occi-wg] Templates (was Re: OCCI Dashboard)

[shlomo.swidler at gmail.com]

On Thu, Jun 25, 2009 at 5:54 PM, Sam Johnston<samj at samj.net> wrote:
> On Thu, Jun 25, 2009 at 4:44 PM, <shlomo.swidler at gmail.com> wrote:
>>
>> On Thu, Jun 25, 2009 at 5:34 PM, Sam Johnston<samj at samj.net> wrote:
>> > On Thu, Jun 25, 2009 at 3:45 PM, <shlomo.swidler at gmail.com> wrote:
>> >>
>> >> 4. How will I be able to discover VM images that are appropriate for
>> >> my "compute"s? For example, Amazon has public AMIs that I can launch
>> >> on my instances, and I can filter the ElasticFox view to only show me
>> >> 64-bit AMIs or otherwise filter them by AMI name. Is this use case
>> >> covered by OVF, or is it more appropriate at the OCCI level?
>> >
>> > This one I have a better answer for, in that there should be no "start"
>> > verb
>> > for a template (e.g. AMI), rather only a "clone" verb which returns a
>> > Location: to a new compute resource (pre-linked to any storage and
>> > network
>> > resources as necessary). We could also bundle templates into a
>> > pre-defined
>> > category, such that machines that are just not startable (e.g. due to
>> > permissions, faults, etc.) don't appear as templates.
>>
>> Sounds strange to me.
>>
>> Sheep aSheep = new Sheep();
>> Object dolly = aSheep.clone();
>>
>> I would expect "dolly" to be of type Sheep, the same type as the
>> object that was cloned.
>
> The original object was a compute resource and the result of "cloning" it is
> a compute resource too - I don't see a problem here (though I agree with
> your argument).
>
>>
>> Perhaps the verb "instantiate" is more appropriate to describe the act
>> of "using a template". But it's harder to spell.
>
> Perhaps, and you're right it is harder to spell. Whatever we choose we just
> need to make sure we define it properly.
>
> For performance reasons it might be useful to be able to "start" a template
> anyway (one call instead of two)... in which case a pre-defined "template"
> category makes sense.
>
> Sam

I had assumed that the original template (AMI) was of type "template"
and not of type "compute resource".

I think it muddies the definitions to call "templates from which
compute resources can be built" by the name "compute resource". So the
idea would be a template, with only three possible verbs:
- clone (create my own copy of this template, owned by me, and not
necessarily visible to the public)
- instantiate or start (create a compute resource based on this
template, like launching an EC2 instance)
- delete (remove a template, assuming I own it and/or have permission
to delete it)

[BTW, the same verbs are what I envisioned for the noun meaning disk
"snapshot"s.]