[libvirt] [RFC] Explicit boot device ordering

[Richard W.M. Jones]

On Tue, Jan 11, 2011 at 03:17:26PM +0100, Jiri Denemark wrote:
> Hi,
> 
> I'm working on $SUBJ and I can't decide on XML representation of that. The
> goal is to let users specify an ordered list of devices to boot from, e.g.,
> 2nd NIC, 1st NIC, 1st CD-ROM, 2nd IDE disk. We already have boot elements in
> /domain/os so we could make use of them or we could add a boot element inside
> device elements.
> 
> So for the first case, we could have something like
> <os>
>     <boot target='net1'/>
>     <boot target='net0'/>
>     <boot target='hdc'/>
>     <boot target='hdb'/>
> <os>
> 
> Where target attributes would match /domain/devices/*/target at dev
> 
> For the second case, appropriate devices would contain <boot order='n'/>
> elements.
> 
> Personally I like the first option more since it is very easy to change boot
> order in that case and the whole boot list is co-located at a single place in
> domain XML.

I agree.  Is it necessarily the case that every boot device is a real
device in the XML?  Maybe there is a system that can boot from
internal ROM or some other abstraction that doesn't correspond to a
libvirt <device>.

> Do you feel the same or do you even have a better solution in your mind?

Well how about ...

  <boot> net1 net0 hdc hdb </boot>

Rich.

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
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