[libvirt] How do I import an old VM image to a new Install

[Cole Robinson]

On 11/25/2009 01:27 PM, Michael N. Moran wrote:
> On 11/25/2009 12:53 PM, Cole Robinson wrote:
>> On 11/25/2009 11:36 AM, Michael N. Moran wrote:
>>> First, I am a casual VM user. I have been using
>>> Fedora Core 7 on my Dell laptop for a couple of
>>> years with a single QEMU/KVM guest running Windoze XP.
>>>
>>> I recently installed Fedora 12 on a new hard disk
>>> and would like to use my old Windows VM image
>>> on the new install.
>>>
>>> Is there an easy way to do this?
> 
>>> libvirtError: operation failed: image magic is incorrect
>>>
>>
>> Restore isn't what you want here, and though the above error sounds
>> scary it is actually correct. Restore starts a VM that was previously
>> 'saved', which is kind of like suspend to ram on a physical machine.
>>
>> You should be able to use virt-install --import to get what you want,
>> something like
>>
>> virt-install --name foo --ram 1024 --os-variant winxp --import --disk
>> path=/path/to/your/disk/image ...
> 
> Thanks Cole, that's what I was looking for. I used the
> following line:
> 
> virt-install --name WindozeXP --ram 512 --os-variant winxp \
> --import --disk path=/var/virt/WindozeXpDisk.raw
> 
> Virt Viewer came up and the XP boot screen was shown for
> about a minute and then the I experienced a BSOD with an
> UNMOUNTABLE_BOOT_VOLUME error.
> 
> I assume that the problem is that I need to specify a
> VM that has the same virtual hardware characteristics as
> my previous environment. I suppose that can be gleaned
> from /etc/libvirt/qemu/WindozeXP.xml or similar.
> 
> I've attached that old WindozeXP.xml file in an attempt
> to be complete.
> 
> If there is an easy way to import that information or
> if I'm on the wrong track, please let me know.
> 

You can use 'virsh edit <vmname>' on the new VM and try to make it match
the old XML as best as possible. A few things to try:

- Sync the mac addresses
- Add <model type='rtl8139'/> to the <interface> block
- Make sure acpi + apic, memory, vcpu settings are the same

It could also be that the jump from f7 to f12 is just too drastic, and
behavior has changed enough at the qemu/kvm level to upset the guest.
Not really sure though.

- Cole