[openstack-dev] [nova] I think nova behaves poorly when booting multiple instances

Chris Friesen chris.friesen at windriver.com
Tue Jun 2 23:25:41 UTC 2015

On 06/02/2015 02:36 PM, Andrew Laski wrote:
> There used to be a project that I think was looking for an API like this to
> provide a reservation system, Climate or Blazar or something.  There was brief
> talk of providing something like it for that use case, but the idea was put on
> the backburner to wait for the scheduling rework that's occurring.
> The question in my mind is should the claim requests be in the Nova API or come
> from a scheduler API.  And I tend to think that they should come from a
> scheduler API.

Who owns the resources, nova or the scheduler?

In many cases only nova-compute can resolve races (resource tracking of specific 
CPU cores, specific PCI devices, etc. in the face of parallel scheduling) so 
unless we're going to guarantee no races then I think claim requests should be a 
nova API call, and it should go all the way down to nova-compute to make sure 
that the resources are actually claimed.


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