[Libvir] VCPU mapping into the XML

[Hugh Brock]

Daniel P. Berrange wrote:
> 
> Libvirt is really just the lowest level is what I see as a stack of tools
> for managing virtual machines. Above libvirt I'd expect to see some form
> of 'policy manager' which defines/controls things such as VCPU mapping,
> or schedular parameters, and even managing when a VM runs at all. One
> simple policy manager might just apply a statically defined VCPU mapping
> when a new guest starts up. A more advanced policy manager would collect
> resource utilization data, perform some analysis on this data, and thus
> apply changes to the VCPU mapping periodically over lifetime of a guest.
> Such VM policy management tools can already just use the existing APIs
> for setting VCPU mapping.
> 
I'd be very excited if we could get to a first cut of a simple policy 
manager in the fedora 8 timeframe. At a minimum, I would think such a 
thing would need to be able to do the following:

1. Store policy information about a guest. At a minimum we would want to 
store cpu pin/weight/cap information; beyond that, dependency 
information (don't start me until some other VM is up and running).

2. Retrieve policy information on request. So for example we might want 
to tell libvirt to ask the manager for policy information before 
starting a guest, or before shutting one down.

Just these features would be great for a first cut. Then going forward, 
we could start thinking about receiving monitoring information and 
responding to events. The tricky thing, it seems to me, is going to be 
designing the thing in such a way that it won't take forever to 
implement the simple part now, but can still be extended to do more later.

Further thoughts, anyone?
--Hugh

-- 
Red Hat Virtualization Group http://redhat.com/virtualization
Hugh Brock           | virt-manager http://virt-manager.org
hbrock at redhat.com    | virtualization library http://libvirt.org