Re: [uml-user] UML root image sharing

[Riccardo M. <ric...@gm...>]

Hello,

On Tue, Feb 14, 2012 at 13:25, Ritesh Raj Sarraf <rr...@re...> wrote:
> Is there a particular format of the root image that UML uses?
>

It's the "raw" image format.

Using the KVM tools, you can create one with "qemu-img create -f raw".

Otherwise just use "dd" as in:

  # create a 2GB raw disk image
  dd if=/dev/zero of=my_uml_disk.img bs=1m count=2048


> My intent is to have one single image and use it across all different
> virtualizations, i.e. use the same image with UML, VirtualBox, KVM etc.
>

Probably the simplest approach is to use KVM or VirtualBox to
install to partition the disk and install the OS on it.  Then you just
pick a UML kernel compatible with the OS on the disk image and start
it.  (I'm not sure VirtualBox can handle "raw" images, though.)

Use LABEL= or UUID= lines in /etc/fstab, or you'll run into troubles
as different virtualization systems use different device names for the
emulated disk (e.g., "/dev/ubda" vs. "/dev/xvda" vs. "/dev/sda" etc.)

Best regards,
Riccardo