Xen users - Sep 2006 - Kernel 2.6 (domain0) and Kernel 2.4 (domainU)???

Hello All

I have Scientific Linux 4 (Kernel 2.6) running at domain0, but i want to
use Scientific Linux 3 (Kernel 2.4) ant domainU. How to compile kernel
2.6-xen0 for domain0 and kernel 2.4-xenU for domainU?
Thanks

Bruno Silva


_______________________________________________
Xen-users mailing list
Xen-users@lists.xensource.com
http://lists.xensource.com/xen-users

Howdy,

On 01.09.2006 12:41, Bruno Rodrigues Silva wrote:
> I have Scientific Linux 4 (Kernel 2.6) running at domain0, but i want to
> use Scientific Linux 3 (Kernel 2.4) ant domainU. How to compile kernel
> 2.6-xen0 for domain0 and kernel 2.4-xenU for domainU?
This is only possbile with an HVM machine. Paravirtualized machines are
using the host kernel.

greetings

Fabian



_______________________________________________
Xen-users mailing list
Xen-users@lists.xensource.com
http://lists.xensource.com/xen-users

> -----Original Message-----
> From: xen-users-bounces@lists.xensource.com 
> [mailto:xen-users-bounces@lists.xensource.com] On Behalf Of 
> Bruno Rodrigues Silva
> Sent: 01 September 2006 11:41
> To: xen-users@lists.xensource.com
> Subject: [Xen-users] Kernel 2.6 (domain0) and Kernel 2.4 (domainU)???
> 
> Hello All
> 
> I have Scientific Linux 4 (Kernel 2.6) running at domain0, 
> but i want to
> use Scientific Linux 3 (Kernel 2.4) ant domainU. How to compile kernel
> 2.6-xen0 for domain0 and kernel 2.4-xenU for domainU?
If you''re using Xen 3.0, you would need to have SVM or VT capable CPU,
as there is no patch to change 2.4 kernel into a Xen-kernel, so you
would have to run full virtualization to do that. 

--
Mats
> Thanks
> 
> Bruno Silva
> 
> 
> _______________________________________________
> Xen-users mailing list
> Xen-users@lists.xensource.com
> http://lists.xensource.com/xen-users
> 
> 
> 


_______________________________________________
Xen-users mailing list
Xen-users@lists.xensource.com
http://lists.xensource.com/xen-users

My experience of a 2.6 kernel on a Scientific3 devfs based domU resulted 
in this (mad&bad) trick:

- update the distro to use kernel26 (on scientific linux cern you have 
instruction to do that) because modutils from 2.4 distro are not 
compatible with 2.6 kernel, off-course  (QM_MODULES errors)
- configure domU to use host 2.6 kernel provided by Xern
- chmod a+rw /dev/*   in /erc/rc.local as last command   to override 
wrong permissions there

no problem resulted from this setup as far as until now.

ivan

Better solution out there are welcome

Fabian Holler wrote:
> Howdy,
>
> On 01.09.2006 12:41, Bruno Rodrigues Silva wrote:
>   
>> I have Scientific Linux 4 (Kernel 2.6) running at domain0, but i want
to
>> use Scientific Linux 3 (Kernel 2.4) ant domainU. How to compile kernel
>> 2.6-xen0 for domain0 and kernel 2.4-xenU for domainU?
>>     
>
> This is only possbile with an HVM machine. Paravirtualized machines are
> using the host kernel.
>
> greetings
>
> Fabian
>
>   
> ------------------------------------------------------------------------
>
> _______________________________________________
> Xen-users mailing list
> Xen-users@lists.xensource.com
> http://lists.xensource.com/xen-users

-- 
www.bio.dist.unige.it
phone: +39 10 353.2789
fax:   +39 10 353.2948


_______________________________________________
Xen-users mailing list
Xen-users@lists.xensource.com
http://lists.xensource.com/xen-users

> -----Original Message-----
> From: xen-users-bounces@lists.xensource.com 
> [mailto:xen-users-bounces@lists.xensource.com] On Behalf Of 
> Fabian Holler
> Sent: 01 September 2006 11:50
> To: xen-users@lists.xensource.com
> Subject: Re: [Xen-users] Kernel 2.6 (domain0) and Kernel 2.4 
> ( domainU)???
> 
> Howdy,
> 
> On 01.09.2006 12:41, Bruno Rodrigues Silva wrote:
> > I have Scientific Linux 4 (Kernel 2.6) running at domain0, 
> but i want to
> > use Scientific Linux 3 (Kernel 2.4) ant domainU. How to 
> compile kernel
> > 2.6-xen0 for domain0 and kernel 2.4-xenU for domainU?
> 
> This is only possbile with an HVM machine. Paravirtualized 
> machines are
> using the host kernel.
You can certainly run a different kernel on the PV guest than the Host
kernel. However, it needs to be patched for the Xen hypervisor version
you''re using, and that will depend on the patches available to work
correctly. It would THEORETICALLY be possible to back-port the Xen 3
interface from 2.6.16 (or such) to 2.4.x, but not enough people seem to
be sufficently motivated to go through this work.... 

--
Mats
> 
> greetings
> 
> Fabian
> 
> 


_______________________________________________
Xen-users mailing list
Xen-users@lists.xensource.com
http://lists.xensource.com/xen-users

Hi
> This is only possbile with an HVM machine. Paravirtualized 
> machines are using the host kernel.
NO.

EACH VM has it''s own kernel!
By design you should be able to use any paravirtualized kernel in any domU
(even different ones at the same time) while using any xen-hosting kernel in
dom0.
There is only ONE restirction: domU''s xen build must not be newer the
the
running supervisor.

Beside that, you simply cannot build any kernel with any version. AFAICT
there is no 2.4 kernel for xen3, you will need to compile the 2.4 kernel
with xen2. However by the rules above, you should still be able to run that
in a xen3 host. (Not the other way around though.)

I need to say, that I didn''t test this myself except for running
3.0.0/1
kernels in a 3.0.2-2 host.

Regards,
  Steffen


_______________________________________________
Xen-users mailing list
Xen-users@lists.xensource.com
http://lists.xensource.com/xen-users

> Beside that, you simply cannot build any kernel with any 
> version. AFAICT
> there is no 2.4 kernel for xen3, you will need to compile the 
> 2.4 kernel
> with xen2. However by the rules above, you should still be 
> able to run that
> in a xen3 host. (Not the other way around though.)
> 
I think the rule of versions only apply for Xen 3 +, so a Xen 2 kernel
will not work on Xen 3.x. I could be wrong, and if anyone knows so,
please say so.

--
Mats



_______________________________________________
Xen-users mailing list
Xen-users@lists.xensource.com
http://lists.xensource.com/xen-users