[openstack-dev] [Congress] [Delegation] Meeting scheduling

Yathiraj Udupi (yudupi) yudupi at cisco.com
Wed Mar 18 01:09:38 UTC 2015

Hi Tim,

I posted this comment on the doc.  I am still pondering over a possibility of have a policy-driven scheduler workflow via the Solver Scheduler placement engine, which is also LP based like you describe in your doc.
I know in your initial meeting, you plan to go over your proposal of building a VM placement engine that subscribes to the Congress DSE,  I probably will understand the Congress workflows better and see how I could incorporate this proposal to talk to the Solver Scheduler to make the placement decisions.

The example you provide in the doc, is a very good scenario, where a VM placement engine should continuously monitor and trigger VM migrations.

I am also interested in the case of a policy-driven scheduling for the initial creation of VMs. This is where say people will call Nova APIs and create a new set of VMs. Here the scheduler workflow should address the constraints as imposed from the user's policies.

Say the simple policy is " Host's free RAM >= 0.25 * Memory_Capacity"
I would like the scheduler to use this policy as defined from Congress, and apply it during the scheduling as part of the Nova boot call.

I am really interested in and need help in coming up with a solution integrating Solver Scheduler, so say if I have an implementation of a "MemoryCapacityConstraint", which takes a hint value "free_memory_limit" (0.25 in this example),
could we have a policy in Datalog

placement_requirement(id) :-
solver_scheduler:applicable_constraints(id, ["MemoryCapacityConstraint", ]),
applicable_metadata(id, {"free_memory_limit": 0.25, })

This policy could be set and delegated by Congress to solver scheduler via the "set_policy" API. or the Solver Scheduler can query Congress via a "get_policy" API to get this policy, and incorporate it as part of the solver scheduler workflow ?

Does this sound doable ?


On 3/16/15, 11:05 AM, "Tim Hinrichs" <thinrichs at vmware.com<mailto:thinrichs at vmware.com>> wrote:

Hi all,

The feedback on the POC delegation proposal has been mostly positive.  Several people have asked for a meeting to discuss further.  Given time zone constraints, it will likely be 8a or 9a Pacific.  Let me know in the next 2 days if you want to participate, and we will try to find a day that everyone can attend.


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