[Engine-devel] oVirt Scheduler API Design

[Gilad Chaplik]

inline.

----- Original Message -----
> From: "Ofri Masad" <omasad at redhat.com>
> To: "Laszlo Hornyak" <lhornyak at redhat.com>
> Cc: "Gilad Chaplik" <gchaplik at redhat.com>, "engine-devel" <engine-devel at ovirt.org>
> Sent: Wednesday, May 29, 2013 9:46:40 AM
> Subject: Re: [Engine-devel] oVirt Scheduler API Design
> 
> Hi Gilad,
> 
> two questions about the 'balance' api.
> 1. do we filter out all VMs which cannot be migrated before passing the list
> to the 'balance' method? otherwise, the user-implemented code may select a
> VM which cannot be migrated for some reason.
> 2. do we make sure that the user-implemented 'balance' method do not select
> the same VM over and over again? if the 'balance' selects a non-migrateable
> VM (like described in 1 above) the VM will not migrate and the exact same
> input will be passed again. (infinite loop)

hi Ofri, 
the answer is no for both questions.
balance is a periodic task that oVirt (we) use for VM balancing, the user can use it for all other actions exposed by the REST and not even use our mechanism (return VM=null), having said that I don't think we should make the api more complicated only because we want the user to work like us.
so yes the user is responsible to prevent loops and not selecting non-migratable vms.

> 
> thanks
> Ofri
> 
> ----- Original Message -----
> > From: "Laszlo Hornyak" <lhornyak at redhat.com>
> > To: "Gilad Chaplik" <gchaplik at redhat.com>
> > Cc: "engine-devel" <engine-devel at ovirt.org>
> > Sent: Wednesday, May 29, 2013 3:23:12 AM
> > Subject: Re: [Engine-devel] oVirt Scheduler API Design
> > 
> > Hi Gilad,
> > 
> > Some questions to start the discussion :)
> > External scheduler API:
> >  - Why are you mixing xml into json?

JSON is preferable. I use xml because the ovirt-python-sdk supports xml->python conversion, and when it'll support JSON we'll use that.


> >  - I am missing from the documentation how the external scheduler can
> >  communicate to the engine

XML-RPC
I think it's written there (somewhere :))

> > 
> > Thx,
> > Laszlo
> > 
> > ----- Original Message -----
> > > From: "Gilad Chaplik" <gchaplik at redhat.com>
> > > To: "engine-devel" <engine-devel at ovirt.org>
> > > Sent: Tuesday, May 28, 2013 4:34:11 PM
> > > Subject: [Engine-devel] oVirt Scheduler API Design
> > > 
> > > Hi all,
> > > 
> > > Attached links for oVirt Scheduler API design wiki page.
> > > 
> > > High level overview: http://www.ovirt.org/Features/oVirtScheduler
> > > Detailed design: http://www.ovirt.org/Features/oVirtSchedulerAPI
> > > 
> > > You are more than welcome to share you thoughts.
> > > 
> > > Thanks,
> > > Gilad.
> > > _______________________________________________
> > > Engine-devel mailing list
> > > Engine-devel at ovirt.org
> > > http://lists.ovirt.org/mailman/listinfo/engine-devel
> > > 
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> > 
>