Open Stack

On 16/10/13 15:58, Mike Spreitzer wrote:
> Zane Bitter <zbitter at redhat.com> wrote on 10/16/2013 08:25:38 AM:
>
>  > To answer your question, the key thing that Heat does is take in two
>  > declarative models and generate a workflow to transform one into the
>  > other. (The general case of this is a stack update, where the two models
>  > are defined in the previous and new templates. Stack create and delete
>  > are special cases where one or the other of the models is empty.)
>  >
>  > Workflows don't belong in HOT because they are a one-off thing. You need
>  > a different one for every situation, and this is exactly why Heat exists
>  > - to infer the correct workflow to reify a model in any given situation.
>
> Thanks for a great short sharp answer.  In that light, I see a concern.
>   Once a workflow has been generated, the system has lost the ability to
> adapt to changes in either model.  In a highly concurrent and dynamic
> environment, that could be problematic.

I think you're referring to the fact if reality diverges from the model 
we have no way to bring it back in line (and even when doing an update, 
things can and usually will go wrong if Heat's idea of the existing 
template does not reflect reality any more). If so, then I agree that we 
are weak in this area. You're obviously aware of 
http://summit.openstack.org/cfp/details/95 so it is definitely on the radar.

cheers,
Zane.