Hi Tim: moving our thread to the mailer. Excited to collaborate!


From: Debo~ Dutta <dedu...@cisco.com>
Date: Wednesday, February 11, 2015 at 4:48 PM
To: Tim Hinrichs <thinri...@vmware.com>
Cc: "Yathiraj Udupi (yudupi)" <yud...@cisco.com>, Gokul B Kandiraju <
go...@us.ibm.com>, Prabhakar Kudva <ku...@us.ibm.com>, "
ruby.krishnasw...@orange.com" <ruby.krishnasw...@orange.com>, "
dilik...@in.ibm.com" <dilik...@in.ibm.com>, Norival Figueira <
nfigu...@brocade.com>, Ramki Krishnan <r...@brocade.com>, "Xinyuan Huang
(xinyuahu)" <xinyu...@cisco.com>, "Rishabh Jain -X (rishabja - AAP3 INC at
Cisco)" <risha...@cisco.com>
Subject: Re: Nova solver scheduler and Congress

Hi Tim

To address your particular questions:

   1. translate some policy language into constraints for the LP/CVP and we
   had left that to congress hoping to integrate when the policy efforts in
   openstack were ready (our initial effort was pre congress)
   2. For migrations: we are currently doing that – its about incremental
   constraints into the same solver. Hence its a small deal ….

Joining forces is a terrific idea. Would love to join the IRC call and see
how we can build cool stuff in the community together. I hope we don’t have
to replicate the vm placement engine while the work that was done in the
community does something very similar (and be adapted)

debo

From: Tim Hinrichs <thinri...@vmware.com>
Date: Wednesday, February 11, 2015 at 4:43 PM
To: Debo~ Dutta <dedu...@cisco.com>
Cc: "Yathiraj Udupi (yudupi)" <yud...@cisco.com>, Gokul B Kandiraju <
go...@us.ibm.com>, Prabhakar Kudva <ku...@us.ibm.com>, "
ruby.krishnasw...@orange.com" <ruby.krishnasw...@orange.com>, "
dilik...@in.ibm.com" <dilik...@in.ibm.com>, Norival Figueira <
nfigu...@brocade.com>, Ramki Krishnan <r...@brocade.com>, "Xinyuan Huang
(xinyuahu)" <xinyu...@cisco.com>, "Rishabh Jain -X (rishabja - AAP3 INC at
Cisco)" <risha...@cisco.com>
Subject: Re: Nova solver scheduler and Congress

Hi Debo,

The 2 efforts share great similarities, which was why we investigated the
state of solver-scheduler.  From what I understand, (i) solver-scheduler
doesn’t currently have a policy language and (ii) it doesn’t do migrations.
 (I realize these are both in the works.)  We needed both and wanted to
make progress before those were complete.

In the long run, it may make perfect sense to replace our vm-placement
engine with yours.  So joining forces sounds like a good idea.  At the very
*least* we ought to keep up to date with each other’s progress.

I’m starting to wonder if we ought to schedule a (bi-) weekly IRC for this
topic.

Tim

On Feb 11, 2015, at 4:35 PM, Debo Dutta (dedutta) <dedu...@cisco.com> wrote:

Hi Tim

This looks awesome. Trying to figure out how this approach is different
from the solver scheduler effort we did? We would be happy to fold our
solver scheduler effort into this (that way you also get code up and
running)

Will also respond on the thread.

thx
debo

From: Tim Hinrichs <thinri...@vmware.com>
Date: Wednesday, February 11, 2015 at 4:11 PM
To: "Yathiraj Udupi (yudupi)" <yud...@cisco.com>
Cc: Gokul B Kandiraju <go...@us.ibm.com>, Prabhakar Kudva <ku...@us.ibm.com>,
"ruby.krishnasw...@orange.com" <ruby.krishnasw...@orange.com>, "
dilik...@in.ibm.com" <dilik...@in.ibm.com>, Norival Figueira <
nfigu...@brocade.com>, Ramki Krishnan <r...@brocade.com>, "Xinyuan Huang
(xinyuahu)" <xinyu...@cisco.com>, "Rishabh Jain -X (rishabja - AAP3 INC at
Cisco)" <risha...@cisco.com>, Debo~ Dutta <dedu...@cisco.com>
Subject: Re: Nova solver scheduler and Congress

Hi Yathiraj,

The group is getting big enough that we’ve decided to move the entire
discussion to the openstack-dev mailing list.  I sent a note today with the
google doc we’re working on.  We’re trying to include
[Congress][Delegation] in the subject line of relevant posts.  Here’s the
gdoc.

https://docs.google.com/document/d/1ksDilJYXV-5AXWON8PLMedDKr9NpS8VbT0jIy_MIEtI/edit?usp=sharing
<https://urldefense.proofpoint.com/v2/url?u=https-3A__docs.google.com_document_d_1ksDilJYXV-2D5AXWON8PLMedDKr9NpS8VbT0jIy-5FMIEtI_edit-3Fusp-3Dsharing&d=AwMF-g&c=Sqcl0Ez6M0X8aeM67LKIiDJAXVeAw-YihVMNtXt-uEs&r=B6BWd4kFfgOzAREgThxkmTZKy7dDXE2-eBAmL0PBK7s&m=no-emyiErtYa3_zneDNhY78LG0mCHc0bgMpXi1StZ7A&s=rLY2ACQqD5EQn3MgOnoX8M_zr9254v-FqhF56wfGpic&e=>

Tim

On Feb 10, 2015, at 11:10 AM, Yathiraj Udupi (yudupi) <yud...@cisco.com>
wrote:

Hi Tim,

Thanks for your response.  I think Congress will have to appreciate
different APIs interacting with multiple components in the OpenStack
ecosystem.  So I will be happy to help figure out the integration plan in
general from the Congress side.

I will  be very interested and glad to participate in the discussions of
designing these interfaces in Congress.   Please share any preliminary
designs you may have.   I had participated in one of the Congress mid-cycle
meet ups, and I am interested in the upcoming work on these kind of
enforcement aspects (reactive, proactive) of Congress.  In terms of Nova
scheduling via Solver scheduler, it will also help us be ready with the
integration points.

Let’s be in sync.

Thanks,
Yathi.


On 2/10/15, 11:03 AM, "Tim Hinrichs" <thinri...@vmware.com> wrote:

Hi Yathiraj,

Thanks for the help!

The reason I asked is that we’re trying to figure out the basic interface
for how two policy engines (in general) ought to interact.  We were hoping
Congress and solver-scheduler had very similar APIs, which would make that
interface relatively simple.  But it sounds like the two systems have
pretty different APIs.  So for now we’ll keep working on that interface,
and once we have something worked out we’ll touch base with you to think
through how an integration might work.

Tim

On Feb 6, 2015, at 11:45 AM, Yathiraj Udupi (yudupi) <yud...@cisco.com>
wrote:

Hi Tim,

Thanks for reaching out.   Currently available documentation is all in the
project README -
https://github.com/stackforge/nova-solver-scheduler/blob/master/README.md
<https://urldefense.proofpoint.com/v2/url?u=https-3A__github.com_stackforge_nova-2Dsolver-2Dscheduler_blob_master_README.md&d=AwMF-g&c=Sqcl0Ez6M0X8aeM67LKIiDJAXVeAw-YihVMNtXt-uEs&r=B6BWd4kFfgOzAREgThxkmTZKy7dDXE2-eBAmL0PBK7s&m=4W62lNEl8JKjwUKKASTM0fjHUVJATmMpEsCoYaeA_OQ&s=1rPI8hfdD9f8_B9_14xALPUjAuJJnWVJRhugMJ16IIk&e=>
Towards the end there are some examples.

To answer your specific questions:

1) How do we change the Nova server-placement policy?  An API call?  A file
on the Nova server?
- Currently the server placement policies are all defined in solver
scheduler in the form of pluggable constraint or cost modules.  So imagine
there will be a policy to place a compute VM close to on a storage volume
host, there is a volume affinity cost module -
https://github.com/stackforge/nova-solver-scheduler/blob/master/nova/scheduler/solvers/costs/volume_affinity_cost.py
<https://urldefense.proofpoint.com/v2/url?u=https-3A__github.com_stackforge_nova-2Dsolver-2Dscheduler_blob_master_nova_scheduler_solvers_costs_volume-5Faffinity-5Fcost.py&d=AwMF-g&c=Sqcl0Ez6M0X8aeM67LKIiDJAXVeAw-YihVMNtXt-uEs&r=B6BWd4kFfgOzAREgThxkmTZKy7dDXE2-eBAmL0PBK7s&m=4W62lNEl8JKjwUKKASTM0fjHUVJATmMpEsCoYaeA_OQ&s=T34XhGj816dbMWcnLKU0Oda99ku1twIhUWN_SLTHPkQ&e=>
and
you will feed the necessary inputs for the policy via scheduler hints that
are induced during the nova API calls, in this case of the volume cost,
 the scheduler hint will be to provide the specific volume id.
- So all these constraint and cost classes are defined the nova conf file,
so all applicable policies are included statically at the moment, and
inputs to the policies are via scheduler hints.
- We are yet to commit the code to dynamically set these policies at
run-time, so we can choose what policies to include.

2) What policy language does solver-scheduler use?
- We haven’t yet added support for a formal policy language, but everything
is implemented as pluggable modules now, and a policy will be simply
defining what constraints or costs to use, for what scenarios.  We plan to
use simple policy rules to define this, and will be added soon in the
roadmap.

3) I presume solver-scheduler *provisions* servers according to policy.
Does it also *migrate* servers when they begin to violate policy?
Yes for provisioning according to policy,  Support for migration is coming
soon, and will utilize the nova migration workflow based on a policy
violation detected by a constraint validator.

Congress could feed some of these policies in terms of selecting our solver
scheduler constraints and costs for specific scenarios, and also feed the
necessary scheduler hints.  So based on the Congress policy, we can select
our constraints and costs, and enable nova server placement accordingly.

Including our small solver scheduler team here from Cisco, we will be glad
to work with the community.

Thanks,
Yathi.



On 2/5/15, 4:22 PM, "Tim Hinrichs" <thinri...@vmware.com> wrote:

Hi Yathiraj,

I had a couple of questions about the nova solver scheduler.  We’re looking
into driving server-placement via policy through Congress and wanted to
understand more about how solver-scheduler works.  If it’s easier to just
point me to docs or examples, that’d be great!





Thanks!
Tim





On Wed, Feb 11, 2015 at 9:01 AM, Tim Hinrichs <thinri...@vmware.com> wrote:

>  Hi all,
>
>  A (growing) group of folks are interested in working on the problem of
> delegating policy from Congress to domain-specific policy engines.  We
> started looking at an NFV use case: migrating VMs to reduce energy
> consumption.  In particular we’re looking into building a VM-placement
> policy engine built on top of a linear programming solver.  Here’s a doc
> with some working notes where we’re trying to figure out how to do the
> translation from Congress policy to the linear program.
>
>
> https://docs.google.com/document/d/1ksDilJYXV-5AXWON8PLMedDKr9NpS8VbT0jIy_MIEtI/edit?usp=sharing
>
>  Tim
>
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-- 
-Debo~
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