openstack team mailing list archive
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Re: Allowing clients to pass capability requests through tags?
On Feb 11, 2011, at 2:12 PM, Jay Pipes wrote:
> Hehe, sounds like something to chat about over a beer at the next
> design summit ;)
Looking forward to it... I enjoyed the last one.
> The issue isn't necessarily how to pass instance type, but how to pass
> *arbitrary* client request parameters, so I thought that user_data in
> the EC2 API was a good place for those, and was wondering (kinda out
> loud ;) ) what the best "field" or "place" would be on the OpenStack
> API side of things for that kind of arbitrary client request
For the EC2 API, I think that we're safer appending key-value pairs to instance_type field. euca2ools just takes the string verbatim. The problem with user_data is it is interpreted by existing images in all sorts of ways. Like if "#!" is the first 2 characters, Ubuntu processes it as a bash shell script. Very handy, bad to break. Lots of cloud users depend on it working. Most cloud development frameworks depend on unmolested user_data, since it is the only way to pass configuration data down to instances easily. I can't think of any other field that makes sense from the EC2-centric perspective.
Also want to stress to think about flavors/instance_types as "advertised" configurations, but that deployments might want to allow even these to be overridden.
Brian Schott, Project Leader
USC Information Sciences Institute
ph: 703-812-3722 fx: 703-812-3712