[openstack-dev] [nova] A prototype implementation towards the "shared state scheduler"

Chris Friesen chris.friesen at windriver.com
Tue Feb 23 23:03:10 UTC 2016

On 02/21/2016 01:56 PM, Jay Pipes wrote:
> Yingxin, sorry for the delay in responding to this thread. My comments inline.
> On 02/17/2016 12:45 AM, Cheng, Yingxin wrote:
>> To better illustrate the differences between shared-state,
>> resource-provider and legacy scheduler, I’ve drew 3 simplified pictures
>> [1] in emphasizing the location of resource view, the location of claim
>> and resource consumption, and the resource update/refresh pattern in
>> three kinds of schedulers. Hoping I’m correct in the “resource-provider
>> scheduler” part.

> 2) Claims of resource amounts are done in a database transaction atomically
> within each scheduler process. Therefore there are no "cache updates" arrows
> going back from compute nodes to the resource-provider DB. The only time a
> compute node would communicate with the resource-provider DB (and thus the
> scheduler at all) would be in the case of a *failed* attempt to initialize
> already-claimed resources.

Can you point me to the BP/spec that talks about this?  Where in the code would 
we update the DB to reflect newly-freed resources?


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