[libvirt] Domain XML format using defined storage volume + RFC

[Stefan de Konink]

On Thu, 15 May 2008, Daniel P. Berrange wrote:

> On Thu, May 15, 2008 at 03:20:06PM +0200, Stefan de Konink wrote:
> > On Thu, 15 May 2008, Stefan de Konink wrote:
> >
> > > Now I wonder, is it possible to have here
> > > somethinglike storage://netapp/lun-0?
> > >
> >
> > [snip]
> >
> > > From the standpoint: we make it easy for the user I would prefer not to
> > > provide a Linux specific path.
> >
> > http://libvirt.org/formatdomain.html#elementsDisks
> >
> > I propose an extension to the current <source> tag specifying where a disk
> > should come from. In my humble opinion something that is already available
> > inside libvirt should be reused.
> >
> > Therefore:
> >
> > source
> >     If the disk type is "file", then the file attribute specifies the
> > fully-qualified path to the file holding the disk. If the disk type is
> > "block", then the dev attribute specifies the path to the host device to
> > serve as the disk.
> >
> >     If the disk type is "pool", then the pool attribute and the volume
> > attibute specify what volume should be used for this disk.
>
> I'd support a syntax like this:
>
>     <disk type="pool">
>       <source pool="myfiler" vol="lun-4"/>
>       <target dev="xvda"/>
>     </disk>

I understand your point :) Nevermind, I think you are right, making a CD
that is backed by a LUN is non-sence anyway.

> > I'm currently playing with xml.c to get it supported. One thing
> > that would be interesting is a 'start' parameter, so when the
> > pool is defined but not yet started it should start. Any comments
> > to the idea?
>
> No, lifecycle changes in one object (the domain) should not effect lifecycle
> changes on another (the storage). We already provide ability for pools to
> be auto-started at time libvirtd starts.  Pools will typically be serving more
> than one guest anyway, so starting a pool upon starting a domain is a niche
> use case. Management tools can provide policy such as auto-starting pools
> in this scenario if desired.

Expect a RFC patch soon ;)


Stefan