[Fedora-xen] VFS: Cannot open root device "sda1" or unknown-block(0, 0)

[Eduardo Pereira Habkost]

On Fri, Oct 12, 2007 at 10:06:43AM -0700, Haifeng He wrote:
<snip>
> >
> > I expect the images you have downloaded have a valid grub configuration
> > inside it. If they have it, you can use:
> >
> > bootloader = "/usr/bin/pygrub"
> >
> > Instead of specifying a kernel that is outside the disk image. Pygrub
> > will be able to read grub configuration and kernel/initrd images from
> > inside the disk image.
> >
> 
> Thank you for your reply. I tried to include bootloader = "/usr/bin/pygrub"
> in my configuration but I got an error message "Error: Boot loader
> didn't return any data!".
> I was able to boot the same image on a Ubuntu system with Xen
> installed from source.
> Do I need to do something special on Fedora-Xen? Or there is a way that I
> can add block device and filesystem modules into the initrd image?

I took a look at the config file shipped with Fedora images on the site
you mentioned. It looks like it expects you to have a pre-compiled domU
kernel that contains all needed modules, on you host /boot directory. I
don't know which kernel image the author of those images expects you
to use.

Some things you can try:

- Checking the instructions on the README.txt inside the image, as noted
  on <http://jailtime.org/download:fedora:fc6>. Maybe there are some
  clues there; or
- Try to generate a initrd that will contain all needed modules. You can
  play with the --omit-* and --with options of mkinitrd to get a initrd
  with the right modules; or
- Try using the Xen kernel and initrd from the FC-6 repository:
  http://download.fedora.redhat.com/pub/fedora/linux/core/6/i386/os/images/xen/
  or
- Get a domU kernel with all needed modules compiled as builtin (so
  you don't need a initrd) from somewhere, or compile a domU kernel this
  way; or
- Put a valid grub configuration (and a kernel-xen package) inside the
  image, to get pygrub to work; or
- Use virt-manager and install your own FC-6 system instead of using
  the downloaded image.

-- 
Eduardo