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On 27 January 2014 18:08, Joshua Harlow <harlowja at yahoo-inc.com> wrote:
> Thanks, guess this is entering the realm of scheduling & group scheduling and how "just the right" level of information is needed to do efficient group scheduling in nova/ironic vs the new/upcoming gantt service.
>
> To me splitting it into N single requests isn't group scheduling but is just more of a batch processor to make things more parallel. To me it seems like gantt (or heat) or something else should know enough about the topology to identify where to schedule a request (or a group request) and then gantt/heat should pass enough location information to nova or ironic to let it know what was selected. Then nova or ironic can go about the dirty work of ensuring the instances were created reliably.... Of course it gets complicated when multiple resources are involved; but nobody said it was going to be easy ;)

Right, it does get complex. One variation for instance - get a
reservation from the scheduler which can schedule across network/block
storage/compute and then follow that up with individual deployment
requests that are tagged with the reservation. That way we don't need
a mega-API that dispatches out to everything.

Anyhow - I believe no matter what that this is future work and Ironic
should be driven by the evolving design, rather than assuming anything
about batch or not batch and changing in advance.

-Rob

-- 
Robert Collins <rbtcollins at hp.com>
Distinguished Technologist
HP Converged Cloud