Re: [Xen-users] xen3 domU on xen4 dom0

[Wolf Grossi <wg1@xxxxxxx>]

On 10.02.2011 06:19, Henrik Langos wrote:
> On Wed, Feb 09, 2011 at 02:17:10PM +0100, Wolfgang Grossbauer wrote:
> > On 08.02.2011 17:26, Henrik Langos wrote:
> > > On Tue, Feb 08, 2011 at 03:26:50PM +0000, Todd Deshane wrote:
> > > > On Tue, Feb 8, 2011 at 2:17 PM, Wolf Grossi<wg@xxxxxxxxxxxxxx>   wrote:
> > > > > Greetings!
> > > > >
> > > > > Trying to to run a xen3 domU on a xen4 dem0 I run into problems.
> > > ...
> > > > > With
> > > > > xm create -c M08
> > > > > I get the following error:
> > > > >
> > > > > XEN1:/etc/xen/vm # Error: (2, 'Invalid kernel', 'elf_xen_note_check: ERROR:
> > > > > Xen will only load images built for Xen v3.0\n')
> > > > >
> > > > > I do not uderstand the above error: the kernel to be loaded *is* a xen-3.0
> > > > > kernel and should be taken from domU:/boot.
> > > > >
> > > > > Now I have the following questions:
> > > > > 1) Can I run xen-3 domU's on a xen-4 dom0?
> > > Yes. I am running a Debian Squeeze Xen 4.0.1 Hypervisor and 2.6.32-5-xen-amd64 
> > > dom0.
> > >
> > > On that I run a couple of older PVM machines that have an 2.6.26-2-xen-686 
> > > kernel.
> > > That is a 32bit kernel compiled for xen 3.2-1.
> > >
> > > Tomorrow I'll try to get my old Etch VMs there too. (2.6.18 32bit domU made for 
> > > Xen 3.0.3)
> > >
> > > > > 2) If yes (hope so :-), what's wrong with the above install/config,
> > > > >     or what have I missed?
> > > I guess your pygrub doesn't find the right kernel on your VM's disk image.
> > >
> > > Try to mount the image in dom0, copy the kernel and initrd to /boot/foo/
> > >
> > > Edit your config file /etc/xen/vm/M08 and replace
> > >
> > >    bootloader      = '/usr/lib/xen-default/bin/pygrub'
> > >
> > > with
> > >
> > >    #bootloader      = '/usr/lib/xen-default/bin/pygrub'
> > >    root = '/boot/foo/vmlinuz-blah'
> > >    ramdisk= '/boot/foo/initrd-blah'
> > >
> > > Don't forget to umount the VM's disk image and try again
> > > xm create /etc/xen/vm/M08
> > >
> > > Good luck :-)
> > >
> > > > You need the "top" Xen version to run as an HVM guest on the bottom
> > > > Xen. So, for your case, make your Xen3 Xen domU an HVM domain. That
> > > > should work.
> > > >
> > > > Hope that helps.
> > > >
> > > > Thanks,
> > > > Todd
> > > AFAIK pygrub is only for PVM, isn't it? So I assume that Wolf tries
> > > to get an older PVM guest to run on a relatively recent hypervisor/dom0
> > >
> > > cheers
> > > -henrik
> >
> > Yes, exactly;
> > I'm trying to run a xen3 paravirt guest (32 Bit)
> > on a xen4 (64 Bit).
> I am doing the same thing here. It even works with _very_ old 2.6.18 kernels
> made for xen 3.0.3. Tried it yesterday and it works like a charm.
>
> > I applied your suggestions, however still the same problem:
> >
> > xm create M08
> > Using config file "/etc/xen/vm/M08".
> > Error: (2, 'Invalid kernel', 'elf_xen_note_check: ERROR: Xen will only
> > load images built for Xen v3.0\n')
> >
> >
> > M08 config for xm:
> > ---
> > root = '/boot/vmlinuz-2.6.11.4-20a-xen'
> > ramdisk= '/boot/initrd-2.6.11.4-20a-xen'
> > disk= [ 'file:/root/M08.raw,xvda,w' ]
> > ---
> Aaaaahhh. My bad!  It is not "root" but "kernel".
>
> It should have been
>
> kernel = '/boot/vmlinuz-foo'
> ramdisk= '/boot/initrd-foo'
> root = '/dev/xvda2 ro'
> disk= [ 'file:/root/M08.raw,xvda,w' ]
>
> But wait a second ... 2.6.11 ??? What is this? The dark ages? ;-)
>
> I am pretty sure that 2.6.11 was not a xen 3 kernel.
>
> cheers
> -henrik
>
> PS: Please use "reply-to-all" to have your reply also on the list.
> Maybe somebody else will find this in the mailing list archive
> before trying to run a 2.6.11 linux on a 4.0 hypervisor.
Henrik, thanks a lot for your time!
Yes, you are right, it's a xen-2.something kernel.
So I guess I have to consider other alternatives (like dump that old 
stuff :-) .
Wolf


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