[openstack-dev] [Nova][Schduler] Volunteers wanted for a modest proposal for an external scheduler in our lifetime

Boris Pavlovic bpavlovic at mirantis.com
Tue Dec 3 12:22:35 UTC 2013

Hi all,

Finally found a bit time to write my thoughts.

There are few blockers that make really complex to build scheduler as a
services or even to move main part of scheduler code to separated lib. We
already have one unsuccessfully effort
https://blueprints.launchpad.net/oslo/+spec/oslo-scheduler .

Major problems that we faced were next:
1) Hard connection with project db api layer (e.g. nova.db.api,
2) Hard connection between db.models and host_states
3) Hardcoded host states objects structure
4) There is no namespace support in host states (so we are not able to keep
all filters for all projects in the same place)
5) Different API methods, that can't be effectively generalized.

Main goals of no-db-scheduler effort are:
1) Make scheduling much faster, storing data locally on each scheduler and
just syncing states of them
2) Remove connections between project.db.api and scheduler.db
3) Make host_states just JSON like objects
4) Add namespace support in host_states

When this part will be finished, we will have actually only 1 problem what
to do with DB API methods, and business logic of each project. What I see
is that there are 2 different ways:

1) Make scheduler as a big lib, then implement RPC methods + bit of
business logic in each project
2) Move all RPC calls from nova,cinder,ironic,... and business logic in 1
scheduler as a service

Best regards,
Boris Pavlovic

On Tue, Dec 3, 2013 at 1:11 PM, Khanh-Toan Tran <
khanh-toan.tran at cloudwatt.com> wrote:

> We are also interested in the proposal and would like to contribute
> whatever we can.
> Currently we're working on nova-scheduler we think that an independent
> scheduler
> is a need for Openstack. We've been engaging in several discussions on
> this topic in
> the ML as well as in Nova meeting, thus we were thrilled to hear your
> proposal.
> PS: I've written in a mail expressing our interest in this topic earlier ,
> but I feel it's better
> to have an more "official submission" to join the team :)
> Best regards,
> Jerome Gallard & Khanh-Toan Tran
> > -----Message d'origine-----
> > De : Robert Collins [mailto:robertc at robertcollins.net]
> > Envoyé : mardi 3 décembre 2013 09:18
> > À : OpenStack Development Mailing List (not for usage questions)
> > Objet : Re: [openstack-dev] [Nova][Schduler] Volunteers wanted for a
> modest
> > proposal for an external scheduler in our lifetime
> >
> > The team size was a minimum, not a maximum - please add your names.
> >
> > We're currently waiting on the prerequisite blueprint to land before
> work starts
> > in earnest; and for the blueprint to be approved (he says, without
> having
> > checked to see if it has been now:))
> >
> > -Rob
> >
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> OpenStack-dev at lists.openstack.org
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