Xen adventures (updating domU's kernel from dom0)

[Ray Van Dolson]

Hello all;

I have a RHEL 5.3 x86_64 dom0 and attempted to install Fedora 10 i386
as a domU.  This of course failed initially due to some kernel bugs,
but I was able to update to 2.6.18-133.el5virttest11xen from clalance's
repo at RH.

Now F10 i386 installs just fine, but of course I managed to neglect
using kickstart to force the use of the PAE kernel.  As a result, my
domU won't boot.

I could reinstall with KS but I thought now would be a good time to try
to get my hands dirty and attempt to replace the kernel myself from the
dom0.

After some trials and tribulations with conflicting VolGroup names, I
finally got my domU mounted under /mnt on dom0, copied in the PAE
kernel RPM's, chroot'd to /mnt and ran rpm -Uvh.  So far so good, but I
then get the following error:

# rpm -Uvh --force kernel-PAE-*.rpm
warning: kernel-PAE-2.6.27.19-170.2.35.fc10.i686.rpm: Header V3 DSA signature: NOKEY, key ID 4ebfc273
Preparing...                ########################################### [100%]
   1:kernel-PAE             ########################################### [ 50%]
grubby fatal error: unable to find a suitable template
   2:kernel-PAE-devel       ########################################### [100%]

Hmm, sure enough, /boot/grub/grub.conf wasn't updated!

Now, I'm guessing I could add the new entry myself and all would be
fine, but I'd like to understand why this isn't working... my theory is
that grubby is confused by the chroot environment somehow and unable to
properly locate my existing grub.conf file or templates?

Any thoughts on this?  A search hasn't yielded much in the way of
answers...

Thanks,
Ray

[Dustin Henning]

While I can't say I know for sure, your guess sounds like a good
one.  I usually have trouble with grub when I boot to a CD for recovery, and
I believe this is on account of the chroot.  I think it is because the
/dev/<disk> information isn't available in the chrooted environment, so grub
can't decide to use (for instance) hd(0,0).  When I have trouble, I am
typically installing grub, though, so I never see your error and can't be
certain the situation is the same.
    Dustin

-----Original Message-----
From: [e-mail] [mailto:[e-mail]]
On Behalf Of Ray Van Dolson
Sent: Friday, March 06, 2009 17:44
To: [e-mail]
Subject: [Fedora-xen] Xen adventures (updating domU's kernel from dom0)

Hello all;

I have a RHEL 5.3 x86_64 dom0 and attempted to install Fedora 10 i386
as a domU.  This of course failed initially due to some kernel bugs,
but I was able to update to 2.6.18-133.el5virttest11xen from clalance's
repo at RH.

Now F10 i386 installs just fine, but of course I managed to neglect
using kickstart to force the use of the PAE kernel.  As a result, my
domU won't boot.

I could reinstall with KS but I thought now would be a good time to try
to get my hands dirty and attempt to replace the kernel myself from the
dom0.

After some trials and tribulations with conflicting VolGroup names, I
finally got my domU mounted under /mnt on dom0, copied in the PAE
kernel RPM's, chroot'd to /mnt and ran rpm -Uvh.  So far so good, but I
then get the following error:

# rpm -Uvh --force kernel-PAE-*.rpm
warning: kernel-PAE-2.6.27.19-170.2.35.fc10.i686.rpm: Header V3 DSA
signature: NOKEY, key ID 4ebfc273
Preparing...                ###########################################
[100%]
   1:kernel-PAE             ########################################### [
50%]
grubby fatal error: unable to find a suitable template
   2:kernel-PAE-devel       ###########################################
[100%]

Hmm, sure enough, /boot/grub/grub.conf wasn't updated!

Now, I'm guessing I could add the new entry myself and all would be
fine, but I'd like to understand why this isn't working... my theory is
that grubby is confused by the chroot environment somehow and unable to
properly locate my existing grub.conf file or templates?

Any thoughts on this?  A search hasn't yielded much in the way of
answers...

Thanks,
Ray

--
Fedora-xen mailing list
[e-mail]
https://www.redhat.com/mailman/listinfo/fedora-xen

[Ray Van Dolson]

On Mon, Mar 09, 2009 at 05:33:01AM -0700, Dustin Henning wrote:
> While I can't say I know for sure, your guess sounds like a good
> one.  I usually have trouble with grub when I boot to a CD for recovery, and
> I believe this is on account of the chroot.  I think it is because the
> /dev/<disk> information isn't available in the chrooted environment, so grub
> can't decide to use (for instance) hd(0,0).  When I have trouble, I am
> typically installing grub, though, so I never see your error and can't be
> certain the situation is the same.
>    Dustin

Thanks Dustin.  I ended up editin the grub.conf file manually, but
after bootup, I just got an error from GRUB saying it couldn't find my
VolGroup.  Oh well.  Embarked on another reinstall, but the whole thing
just locks up way too much.

I think 32-bit Fedora on 64-bit RHEL5 dom0 is not quite ready to work
yet. :-)  Guess I'll go download 64-bit Fedora...

Ray