Open Stack

Hey all,

I was looking through some of the api calls, in particular creating a
server on the openstack api.  I'm not too excited by how long it takes,
and was wondering what people think about making it more asynchronous.
Basically, wondering if making it so that the POST to the nova API doesn't
actually check to make sure we have a valid image, but instead just assume
the user knew what they were doing and pass the image down is something
that people buy.  If the image is invalid (doesn't exist, no permission to
use that image, flavor size doesn't match the minimum requirements of the
image) then we would set the server to error and be done.

There is an obvious drawback: losing the ability to fail fast.  I think we
need to look at embracing the overall asynchronous nature of the API as
much as possible, and rely on client side tools to do upfront validation
where appropriate - nova client would already prevent this from happening
on a nonexistent image, for example.

The API spec doesn't specify anything one way or the other about this - so
another route is to make this a configuration option.

By the way, I don't want this to be construed in any way, shape or form as
me not wanting to improve the performance of glance.  Of course we want
that, but we also know that any additional latency hurts performance.

Thoughts? Are the benefits of fail fast out-weighing our performance
needs?  


Gabe