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

Chris Friesen chris.friesen at windriver.com
Wed Jun 3 02:17:47 UTC 2015


On 06/02/2015 07:48 PM, Jay Pipes wrote:
> On 06/02/2015 07:25 PM, Chris Friesen wrote:

>> 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.
>
> That's actually how the system works today. And, IMHO, it's inefficient. The
> nova-compute node should be the final arbiter of whether a request for resources
> can be properly fulfilled by the hypervisor, however, the scheduler should be
> the thing that "owns" resource usage records for the partition of resource
> providers that the scheduler process is responsible for.

If the nova-compute node is still the final arbiter, what does it actually mean 
to say that the scheduler "owns" the records?

Chris



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