[CentOS-virt] Has anyone been able to start a Fedora 16 VM in Xen PV?

Wed Jan 11 23:09:59 UTC 2012
Norman Gaywood <ngaywood at une.edu.au>

On Tue, Jan 10, 2012 at 05:59:56PM +0400, Eugene Chupriyanov wrote:
> I've managed to setup F16 PV-guest domU under Xen Cloud Platform. It's 
> more than just Xen, but solution will be the same.
> So what you need to do:
> 1) Don;t use GPT (install with nogpt kernel parameter)
> 2) Create bootable /boot partition using ext2 filesystem
> 3) pygrub looks for grub.cfg in /boot/grub directory (to be exact in 
> /grub on /boot fs). But in F16 grub is located ion /boot/grub2.
> So I just copied grub.cfg from /boot/grub2 to /boot/grub. Maybe there is 
> a better way to keep up-to-date copy of grub.cfg in /boot/grub.
> 4) pygrub bootloader fails on following line in default grub.cfg:
> set default="${saved_entry}"
> so I've replaced it with:
> set default=0
> That should be enough to make f16 to run in PV mode.

Yes, thanks for that! This works for me. How did you know that pygrub
failed on that line?

Anyway, my steps to get F16 going under Centos 5.7 with
xen-3.0.3-132.el5_7.2 were:

1. Create a new PV guest and boot the F16 install image with the nogpt
kernel parameter.

2. After install has finished and before you reboot,
switch to text console on ALT-F2 of your install and copy the
/mnt/sysimage/boot/grub2/grub.cfg to /mnt/sysimage/boot/grub/grub.cfg
and edit the line:

set default="${saved_entry}"


set default=0

And that's it. The F16 should boot now. The only difference to Eugene's
steps is that I didn't worry about the ext2 boot partition. Mine is

Also note that the copy and edit in step 2 should be easy to put in a
kickstart file.

If you forget to do step 2, you can do it on the host with, in my case,
kpartx, mount, and edit the files there. Remember to do a:

echo 1 > /proc/sys/vm/drop_caches

so that pygrub will read to changes and not use the cached version.

And finally, when xen-3.0.3-135 is released, it should fix this problem.

I also had success with doing an F15 install, doing an upgrade to F16
and not updating the boot loader. I then manually created a grub.cfg
file. After that F16 booted OK.

I did not try R P Herrold's solution of using an F15 install, installing
fedora-release-16-1.noarch.rpm with rpm, then doing a yum update.

Thanks all you your help.
Norman Gaywood, Computer Systems Officer
University of New England, Armidale, NSW 2351, Australia

ngaywood at une.edu.au            Phone: +61 (0)2 6773 3337
http://mcs.une.edu.au/~norm    Fax:   +61 (0)2 6773 3312

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