Open Stack

Dear all,

We have started working on implementation of CPU reservation/entitlement 
mechanism in Nova (
https://blueprints.launchpad.net/nova/+spec/cpu-entitlement).
The idea is to allow associating explicit CPU allocation guarantees, in a 
more flexible way than it is done today in CoreFilter -- the user/admin 
will be able to define different CPU allocation guarantees for different 
instances. The approach we are taking is to use extra_specs of instance 
types to indicate the desired level of CPU allocation guarantees per vCPU 
(e.g., low=25% of a physical CPU, normal=50%, high=100%), which would 
apply to all instances created from the corresponding type. This fits 
nicely the resource model of most of the hypervisors, which have support 
for CPU guarantees built-in. For KVM, we are implementing the allocation 
guarantees using cpu shares in cgroups (by controlling the cpu shares of 
each instance and the total amount of shares allocated on a host). You can 
find more details in the wiki page linked from the blueprint.

Would appreciate thoughts whether the approach we are taking makes sense, 
or any other feedback.

Thanks!
Alex


--
Alex Glikson
IBM Research
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.openstack.org/pipermail/openstack-dev/attachments/20130114/1fbe1ff5/attachment.html>