[Libguestfs] ovirt VM image to BM

[Laszlo Ersek]

On 05/18/22 14:56, Richard W.M. Jones wrote:
> 
> On Wed, May 18, 2022 at 01:20:27PM +0200, Guilherme De Oliveira Santos wrote:
>> Greetings masters,
>>
>> I got pointed to you guys as experts on smtg I'm struggling with.
>> I'm trying to move an ovirt vm raw image to a bm machine and though
> [bm = baremetal]
>> I could do it successfully using dd (got able to see and work with
>> the partitions and the data fine), I couldn't boot the disk.
>>
>> It may be an issue with drivers (like the virtio drivers), but idk,
>> and I'm wondering if someone has done smtg similar or could help
>> somehow with the process.
> 
> So in IRC we established that it's a RHEL 8.6 guest, and that it
> doesn't get as far as grub.  The virtual machine boots with UEFI and
> the physical machine boots with BIOS which is why grub doesn't work.
> 
> Conversion of a machine from UEFI to BIOS is usually quite tricky.
> Are you sure the baremetal machine doesn't support UEFI booting?
> Almost anything made in the last 10 years should, although you may
> have to adjust the firmware ("BIOS") configuration.

I agree that Guilherme should first try to make the UEFI boot path work
-- dependent on the partitioning of the VM disk image (GPT?), I figure
there might not be a *place* on the physical disk to install BIOS grub2 to!

Thanks
Laszlo

> 
> After that it'll probably not have the right drivers in the initramfs.
> Symptoms would be that it gets to grub, then boots the kernel, but
> fails when mounting the root filesystem.  Luckily this is easier
> to solve - identify which drivers are needed for the target
> hardware and before copying across, run “dracut --add-drivers ..”
> You'll have to read the dracut man page closely.
> 
> Rich.
>