[Libvir] Request for additional entry points

Daniel Veillard veillard at redhat.com
Tue Apr 18 20:40:13 UTC 2006

On Tue, Apr 18, 2006 at 08:11:46PM +0100, Daniel P. Berrange wrote:
> On Tue, Apr 18, 2006 at 12:40:01PM -0400, Daniel Veillard wrote:
> >   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.

  Can you explain your problems in more functional terms. Even with a PhD in CS
I have troubles mapping your explanations to concrete case.
  So we have 2 more APIs which allows to define the XML for a domain
and name it. That then allow to reserve that name, and the domain may be started
later with a simpler API. As far as I know that would not change any other
API except, except maybe listing domains (though I would rather advocate
a new API for listing those non-running domains). So where is your problem
exactly ? What master model does this break ? As far as I can tell the only
change to the current set of API is that you can reserve a domain name without
having it running and then a lookup for such a name will bring back this 
defined but not running domain. Existing code behaviour would remain exactly
unchanged, unless you pick a an already defined name.

> 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?

  Reserve a domain name for example.


Daniel Veillard      | Red Hat http://redhat.com/
veillard at redhat.com  | libxml GNOME XML XSLT toolkit  http://xmlsoft.org/
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