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Re: Allowing clients to pass capability requests through tags?


2011/2/11 Jay Pipes <jaypipes@xxxxxxxxx>:
> On Thu, Feb 10, 2011 at 7:21 PM, Brian Schott <bfschott@xxxxxxxxx> wrote:
>> Justin,
>> Our USC-ISI team is very interested in this.  We are implementing different architecture types beyond x86_64.  We are also interested in suggesting switch topology for MPI cluster jobs, passing in requests for GPU accelerators, etc.  Currently, our approach has been to specify these through instance_types. What you describe is more flexible, but I wonder if for EC2 api we could stretch the -t flag.
> Just to make something clear, the EC2 API has nothing to do with the
> -t flag.

Sorry, what? It's passed verbatim in the EC2 RunInstances API call:


..so it's certainly part of the API.

> That is specific to the eucatools (or ec2 CLI tools).  The
> request that goes through to the EC2 API controller (in nova, this is
> nova.api.ec2.cloud.CloudController), passing to the controller an XML
> packet that has a variety of fields that the controller then looks for
> in populating the database with information about the instance to spin
> up.

This doesn't sound familiar at all. Can you provide a reference to any of this?

> Tacking on something to the -t flag would be a total hack that
> wouldn't be particularly future-proof.

Actually, given the limitations the EC2 imposes, I think it's actually a pretty
good idea. I can't think of a better way to attempt to expose this in
the EC2 API.

> I think that perhaps the user_data field in the XML might be a better
> choice, since this has a more free-form capacity than a very specific
> instance_type code that the EC2 API controller looks for.

The user-data field is used by the user to pass information through to
the instance. It's typically used for post-boot configuration of sorts
for the VM's. If we steal it for this purpose, we lose the ability to
pass stuff this way.

Soren Hansen
Ubuntu Developer    http://www.ubuntu.com/
OpenStack Developer http://www.openstack.org/

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