Re: [Xen-devel] Re: is the xen toolstack backwards compatible ?

[Christoph Egger <Christoph.Egger@xxxxxxx>]

On Wednesday 09 December 2009 16:14:57 Dan Magenheimer wrote:
> Hi Christophe --
>
> What is the earliest version of the tools for which this will work?

Xen-unstable.

> For example, can it be used to switch back and forth between
> a 3.4.0-based Xen/toolstack and a xen-unstable-based Xen/toolstack
> on the same machine?  If so, I would appreciate more information!

Yes, that is possible. Install Xen-unstable in a different directory
than you are "forced" to install Xen 3.4 to.

You can switch forth and back between Xen-unstable and Xen 3.4
by setting the environment variables as described.

Whenever you switch forth and back you have to consider to adapt
the guest config files.
Xen 3.4 requires the full path to hvmloader and to qemu-dm while
the path is optional in Xen-unstable.

Be sure that the correct hvmloader and qemu-dm is used
when you switch.

The same way you can also switch back and forth between
Xen 3.3 and Xen-unstable.

Christoph



> Thanks,
> Dan
>
> > -----Original Message-----
> > From: Christoph Egger [mailto:Christoph.Egger@xxxxxxx]
> > Sent: Wednesday, December 09, 2009 4:43 AM
> > To: Sander Eikelenboom
> > Cc: xen-devel@xxxxxxxxxxxxxxxxxxx; Keir Fraser
> > Subject: [Xen-devel] Re: is the xen toolstack backwards compatible ?
> >
> > On Wednesday 09 December 2009 12:25:40 Sander Eikelenboom wrote:
> > > Hmmm so i could make  the paths:
> > >
> > > export LD_LIBRARY_PATH="/usr/local/lib/<xen_hypervisor_version>"
> > > export
> >
> > PYTHONPATH="/usr/local/lib/<xen_hypervisor_version>/python2.5/
> > site-packages
> >
> > >"
> > >
> > > And let a startup script make symlinks to the right tools for the
> > > hypervisor version that is booted (and perhaps config
> >
> > files), then the only
> >
> > > place to worry about hypervisor and kernel version is grub.
> >
> > Quite.
> >
> > In your case I would compile the tools with
> > PREFIX="/usr/<xen_hypervisor_version>"
> > and set
> >
> > export LD_LIBRARY_PATH="/usr/<xen_hypervisor_version>/lib"
> > export
> > PYTHONPATH="/usr/<xen_hypervisor_version>/python2.5/site-packages"
> > export PATH="$PATH:/usr/<xen_hypervisor_version>/sbin"
> >
> > Then a simple 'xend start' on the command line (or via
> > startup script) is
> > enough.
> >
> > > But i think it's perhaps not worth the trouble and a bit
> >
> > ugly to make that
> >
> > > general, so just drop the idea :-)
> >
> > I do that manually and that works great to switch between
> > different versions
> > for my development/testing effort.
> >
> > Christoph
> >
> > > --
> > >
> > > Sander
> > >
> > > Wednesday, December 9, 2009, 11:06:58 AM, you wrote:
> > > > On Wednesday 09 December 2009 08:22:14 Keir Fraser wrote:
> > > >> On 09/12/2009 00:23, "Sander Eikelenboom"
> >
> > <linux@xxxxxxxxxxxxxx> wrote:
> > > >> > So if it was no coincidence but desirable, at the
> >
> > moment xend and
> >
> > > >> > xentop from unstable don't seem to work on 3.4.2
> >
> > hypervisor anymore.
> >
> > > >> There's no compatibility guarantee across different
> >
> > major Xen releases.
> >
> > > >> But Christoph Egger did a lot of work to allow multiple
> >
> > toolstacks to be
> >
> > > >> installed side by side. I think you should just need to specify a
> > > >> PREFIX=/path/to value when building the tools. Is that
> >
> > right, Christoph?
> >
> > > > Yes, this is right.
> > > > *Before* you start xend, you need to set two environment variables
> > > > LD_LIBRARY_PATH and PYTHONPATH.
> > > >
> > > > Here is an example for PREFIX="/usr/local" and compiled
> >
> > with python 2.5:
> > > > export LD_LIBRARY_PATH="/usr/local/lib"
> > > > export PYTHONPATH="/usr/local/lib/python2.5/site-packages"
> > > >
> > > > If these are not set correct, python tells you it can't
> >
> > find its modules
> >
> > > > or the dynamic linker tells you it can't find the shared
> >
> > libs built from
> >
> > > > tools/libxc.
> > > >
> > > > You should use the same python version you compiled with.
> > > > If you are on a machine where 'python' does not exist as
> >
> > a symbolic link
> >
> > > > to the installed python version (like me on NetBSD) you
> >
> > need the attached
> >
> > > > patch or all python programs installed with "INSTALL_PYTHON_PROG"
> > > > end up with '#!' in the first line instead of
> >
> > '#!/path/to/python2.5'
> >
> > > > which is stupid.
> > > >
> > > > I already submitted attached patch earlier but Ian
> >
> > Jackson objected it
> >
> > > > because he wants a way to have tools working with a
> >
> > different python
> >
> > > > version than it has been compiled with. This sounds
> >
> > obscure to me when
> >
> > > > looking at the path python modules get installed to.
> > > >
> > > > Keir: Please take attached patch. This is better than the current
> > > > situation regardless Ian likes it or not. In the latter
> >
> > case taking the
> >
> > > > patch should motivate him to come up with a patch finally. :)
> > > >
> > > > Again:
> > > > Signed-off-by: Christoph Egger <Christoph.Egger@xxxxxxx>
> >
> > --
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> > Karl-Hammerschmidt-Str. 34, 85609 Dornach b. Muenchen
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> >
> >
> > _______________________________________________
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-- 
---to satisfy European Law for business letters:
Advanced Micro Devices GmbH
Karl-Hammerschmidt-Str. 34, 85609 Dornach b. Muenchen
Geschaeftsfuehrer: Andrew Bowd, Thomas M. McCoy, Giuliano Meroni
Sitz: Dornach, Gemeinde Aschheim, Landkreis Muenchen
Registergericht Muenchen, HRB Nr. 43632


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