[Libvir] OpenVZ XML format and VPS properties get/set interface [long]

[Daniel P. Berrange]

On Mon, Jul 23, 2007 at 11:55:19AM +0100, Richard W.M. Jones wrote:
> Shuveb Hussain wrote:
> >One of the main reasons many people(especially hosting providers) use
> >OpenVZ is since it can be used to provide service level agreements.
> >There must be a way to set/get various VPS parameters from libvirt. I
> >understand concerns about driver specific code in libvirt based clients
> >like virt-manager. The capabilities paradigm will not fit here, since
> >this is simply about various properties of the VE/domain, not the
> >hardware or the VM capabilities. Please correct me, if I am wrong. So,
> >how to we do it?
> 
> Is the current virDomainGetSchedulerType /
> virDomainGetSchedulerParameters / virDomainSetSchedulerParameters API 
> sufficient to express all (or at least most) of what OpenVZ requires? 
> If not, could it be plausibly extended, or is another API needed?

I don't think we should use the virDomain*Scheduler APIs for anything other
than schedular parameters. If we want to provide a means to also controlling
the other various resouce utilization tuning parameters we should have a
set of APIs explicitly for resource tuning parameters. Even if they turn
out to look near identical to the schedular params, I think its important
to keep things semantically separated.

We'll eventually get ability to control various resource tunables on Xen
and QEMU/KVM too - controlling throughput / QOS on virtual NICs, or the
I/O elevator on disk backends, etc. So a formal 'resource tunables' API
would be useful to more than just OpenVZ in the longer term.

Regards,
Dan.
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