[libvirt-users] kvm virtual server boot order

[Jiri Denemark]

> Given the scenario where the disks of a virtual server are defined in the
> following order
> 
>       harddisk hda
>       harddisk vda
>       cdrom vdb
>       cdrom hdb
> 
> Boot device type is crdom.  Which cdrom device will be boot attempted?
> >From the above links, I'm guessing that hdb will be boot attempted. Is this
> the actual behavior?

That depends on BIOS implementation used by qemu and to be honest, I'm not
sure what the default behavior is; you would need to try that :-)

However, if you have new enough libvirt (>= 0.8.8), qemu and SeaBIOS (AFAIK
qemu >= 0.14.0 should be ok), you can better control boot order by using
per-device boot configuration. That is, instead of specifying

    <os>
      ...
      <boot dev='cdrom'/>
    </os>

you would use something like

    <devices>
      ...
      <disk type='file' device='cdrom'>
        ...
        <boot order='1'/>
      </disk>
    </devices>

It's also documented in libvirt XML documentation at
http://www.libvirt.org/formatdomain.html#elementsDisks

Jirka