[Ovirt-devel] Issue with ISO provisioning

[Daniel P. Berrange]

On Wed, Oct 15, 2008 at 09:21:10AM -0400, Hugh O. Brock wrote:
> On Tue, Oct 14, 2008 at 10:11:01PM -0400, Perry Myers wrote:
> 
> [snip]
> 
> >
> > So Windows installs right now work because the soft reboot in step 3 does 
> > not cause the vm to shutdown.  If it did that, the restart of the vm 
> > would come up without the ISO in the drive (since that is a temporary 
> > association)
> >
> > We've talked in the past about changing domains so that on reboot the vm  
> > is destroyed and then restarted by taskomatic.  This way the boot device  
> > can be toggled between reboots.  This fixes linux PXE provisioning, which 
> > right now has a problem because after OS installation over PXE boot the  
> > domain soft reboots and tries to PXE again.
> >
> > So it seems the requirements for Windows and Linux provisioning are  
> > somewhat at odds.  What we may have to do is make it so taskomatic is  
> > aware of the OS type and sets up the semantics of domain rebooting  
> > accordingly.
> 
> Yes, this is exactly the same song-and-dance we went through with
> python-virtinst when getting Windows installs to work from
> virt-manager. What we need to do is figure out a good abstraction for
> the various possible install modes and either a. allow the user to
> specify what's desired, or preferably b. figure it out ourselves.
>
> What we want is some way to say "OK, the install is finished, now
> change the VM to boot in the proper permanent configuration." If we
> always set VMs to halt on reboot and we have a way for taskomatic to
> detect that a VM has halted in mid-install, we could have the UI pop
> up a message asking the user if the install finished? It would be
> difficult to make that clear but it could work, I think...

Two ideas

 - The BIOS boot device is not a single device, but actually a list
   of devices, so you can do

         <boot dev='cdrom'/>
         <boot dev='hd'/>

   and it'll try 'cdrom' first, falling back to 'hd'.

 - The installer will try to eject the CDROM media inside the guest,
   so if we could make sure it stays ejected we wouldn't need to
   change the XML


Alternatively setup boot order

    <boot dev='hd'/>
    <boot dev='cdrom'/>

and dd 512 zero bytes to the disk before booting the installer so it 
picks the cdrom first time, and on 2nd boot will find the harddisk
bootsector.

NB, we didn't do this with virt-install because we didn't want to
make changes to their disk by accident, but maybe its more acceptable
for oVirts use case where things are more tightly  managed


Daniel
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