[Libvir] Request for additional entry points

Daniel P. Berrange berrange at redhat.com
Tue Apr 18 19:11:46 UTC 2006

On Tue, Apr 18, 2006 at 12:40:01PM -0400, Daniel Veillard wrote:
> On Fri, Apr 14, 2006 at 10:38:23AM -0400, Bret McMillan wrote:
> > I think we're confusing the notion of what a passive domain is with what
> > config files happen to be sitting on / exposed to the dom0 machine.  I
> > could very easily look at having an rdbms store the info about the
> > passive domain, hand that down to the dom0 via rpc, and directly call
> > the createLinux call.  To me, that's still a passive domain, even though
> > it's configs haven't touched disk yet.
>   Yup, to me they are different level.
> > I guess I'm also struggling to understand why you'd toss this into
> > xenstore... it just seems this is a higher level concept that needs to
> > be tracked in too specific a way by management systems.
>   The reason it would be useful to save this in xenstore is to garantee
> the same vision between different application managing that node (for example
> a remote supervision tool and a local launcher used by the user). Otherwise

The trouble is this imoses a representational model on the application, which does
not neccessarily mesh with the requirements of the application. So by having
this in libvirt/xenstore, either the application's model will be compromised,
or the app will have its master model how it likes & have to worry about keeping
a denormalization of the master model synced to libvirt / xenstore. In the latter
case, you're now loosing the guareentee of shared app vision this was trying to 
achieve in the first place.

> just keeping this information in libvirt own memory would be just fine,
> I'm still unsure the need to synchronize is really there.

What would be the application gain in this scenario - why wouldn't the app
just store manage it directly itself & pass the XML to libvirt at time of
domain creation?

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