Convert KVM images to Virtual Box (VDI)

It took a while to get the KVM image working with Sun virtual box.

The advantages of a virtual box image is, you can run it on any platform (linux, mac or windows), works without virtualization enabled processor and will work on a 32bit machine
Here are the steps to create an image that works with virtual box:

From the KVM installed server

$ qemu-img convert kvm-os.img -O raw kvm-os-raw.img

Copy the image (kvm-os-raw.img) to virtual box machine

$ VBoxManage convertfromraw --format VDI kvm-os-raw.img vbox.vdi

Converting from raw image file=”kvm-os-raw.img” to file=”vbox.vdi”…
Creating dynamic image with size ….

This will create a virtual box compatible image
Incase required you can compact the image to actual size

$ VBoxManage modifyvdi /home/user/vbox.vdi compact

0%…10%…20%…30%…40%…50%…60%…70%
Here the path to vdi image must be absolute.

Now you can create a new virtual machine from virtual box console/command line, with the vdi image as storage.
Boot the machine and hope for the best 🙂
But it wasn’t easy for me even after this beautiful vdi image, boot hangs with a kernel panic, file system not found.

To fix this issue, we need to recreate the initrd image in the virtual machine:
instructions to do it for redhat:
– Boot the virtual machine in rescue mode with Redhat CD

> linux rescue

# chroot /mnt/sysimage

take a backup of existing initrd

# cp /boot/initrd-2.6.xxx.img initrd-2.6-old

create new initrd image

# mkinitrd -v /boot/initrd-new.img kernel-version

// eg: mkinitrd -v /boot/initrd-new.img 2.6.18-194.8.1.el5

edit the grub configuration and replace the initrd image name with new one

# cat /boot/grub/menu.lst

Reboot the machine and see if it boots 🙂

Hope this will be helpful for someone, I spent hours to get it working 🙂 .
./arun

  • Fouad

    Thanks it worked
    I wanted to migrate to VBOX because KVM doesn’t support bridging with network manager enabled on Fedora and I use network manager on my laptop so I moved to VBOX and it worked perfectly with bridging mode and network manager enabled, Iam not sure why KVM make it harder some times.

    • http://arunnsblog.com/ Arun N S

      KVM usually works with bridge interface, hope at some point network manager supports bridging, other wise just forget about the network manager and do the manual configuration 🙂