how do I setup a Ubuntu domU guest on a CentOS / Fedora Core XEN server?

SoftDux · 07-27-2008, 12:31 PM

Hi all,

Does anyone know how to install Ubuntu (either 7.10 or 8.04) as a XEN domU guest on a CentOS 5 / Fedora Core 8 XEN dom0 server?

I have tried installing Ubuntu as a fully virtualized guest, but the Ubuntu CD doesn't even bootup. I get the Linux bootloader, and that's it,it doesn't continue to boot. Odd.

When trying to install a Paravirtualized guest, I had to use the debootstrap method, but can't get it to boot up.

Quote:

xm create anya_zanet
Using config file "/etc/xen/anya_zanet".
Error: (2, 'Invalid kernel', 'xc_dom_find_loader: no loader found\n')

This is the xen configuration:

Code:

kernel = "/boot/vmlinuz-2.6.23.1-42.fc8"
ramdisk = "/boot/initrd-2.6.23.1-42.fc8.img"
builder='linux'
memory = 256
name = "anya_zanet"
vcpus = 1
vif = [ 'bridge=xenbr0' ]
disk = [ 'phy:/dev/System/anya_zanet,hda1,w' ,  'phy:/dev/System/anya_zanet,hda2,w' ]
root = "/dev/hda1 ro"
on_poweroff = 'destroy'
on_reboot   = 'restart'
on_crash    = 'restart'

So, does anyone know how to get Ubuntu working on a CentOS / Fedora Core XEN server?

Pearlseattle · 07-29-2008, 05:59 AM

Well, if I understood correctly your setup (fc8 as dom0, ubuntu as domU), the configuration line of the domU...

Quote:

kernel = "/boot/vmlinuz-2.6.23.1-42.fc8"

...is currently targeting the kernel of your dom0, or not? I might be wrong, but I really don't think that the kernel of dom0 should be used in any case - doesn't matter if paravirtualized or fully virtualized.

My paravirtualized domUs use their own kernel, but in your case if you want to run Ubuntu as a fully virtualized domU you should probably tell Xen to use the fake kernel coupled with qemu which will fully emulate the I/O devices. I think this works exactly the same way as if you would like to run Windows as a domU, therefore with ...

Quote:

kernel = '/usr/lib64/xen/boot/hvmloader'
builder = 'hvm'
device_model='/usr/lib64/xen/bin/qemu-dm'

...I mention here.

And one more thing: it would be better if you would first create an image of the Ubuntu-dvd with "dd" and refer in the configuration file to the image and not to the physical dvd-drive - the installation will be faster and I think there were/are some problems concerning reboots of the domU and not being able anymore to access the dvd-drive if that was used to perform the first boot.