Xen devel - Dec 2009 - is the xen toolstack backwards compatible ?

Hello Keir,

Perhaps it was coincidence, but if i remember well, booting a 3.4.* hypervisor
with the toolstack from a newer xen version (aka xen-unstable) seemed to work.
The thing is, default a xen build installs the different hypervisor versions
beside each other, and you can use them as such in your grub config, the same
with kernels.
But the toolstack (xend, xm, xentop etc.) gets overwritten. So after trying out
a new hypervisor, you have to reinstall your old toolstack before booting in a
older hypervisor.

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.

-- 
Best regards,
 Sander                          mailto:linux@eikelenboom.it


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On a separate thread, I''ve observed that the toolstack
incompatibility seems to appear between c/s 20070 and
20072.  I don''t think backwards compatibility is
guaranteed but I agree it is desirable when possible.
> -----Original Message-----
> From: Sander Eikelenboom [mailto:linux@eikelenboom.it]
> Sent: Tuesday, December 08, 2009 5:23 PM
> To: Keir Fraser
> Cc: xen-devel@lists.xensource.com
> Subject: [Xen-devel] is the xen toolstack backwards compatible ?
> 
> 
> Hello Keir,
> 
> Perhaps it was coincidence, but if i remember well, booting a 
> 3.4.* hypervisor with the toolstack from a newer xen version 
> (aka xen-unstable) seemed to work.
> The thing is, default a xen build installs the different 
> hypervisor versions beside each other, and you can use them 
> as such in your grub config, the same with kernels.
> But the toolstack (xend, xm, xentop etc.) gets overwritten. 
> So after trying out a new hypervisor, you have to reinstall 
> your old toolstack before booting in a older hypervisor.
> 
> 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.
> 
> -- 
> Best regards,
>  Sander                          mailto:linux@eikelenboom.it
> 
> 
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@lists.xensource.com
> http://lists.xensource.com/xen-devel
>
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Dan Magenheimer wrote:
> On a separate thread, I''ve observed that the toolstack
> incompatibility seems to appear between c/s 20070 and
> 20072.  I don''t think backwards compatibility is
> guaranteed but I agree it is desirable when possible.
I don''t agree with you, and the backward compatibility should be still
kept after merging these Csets, and any dom0 or userspace''s toolstack
changes are not needed for them.  :)
Xiantao
 
>> -----Original Message-----
>> From: Sander Eikelenboom [mailto:linux@eikelenboom.it]
>> Sent: Tuesday, December 08, 2009 5:23 PM
>> To: Keir Fraser
>> Cc: xen-devel@lists.xensource.com
>> Subject: [Xen-devel] is the xen toolstack backwards compatible ?
>> 
>> 
>> Hello Keir,
>> 
>> Perhaps it was coincidence, but if i remember well, booting a
>> 3.4.* hypervisor with the toolstack from a newer xen version
>> (aka xen-unstable) seemed to work.
>> The thing is, default a xen build installs the different
>> hypervisor versions beside each other, and you can use them
>> as such in your grub config, the same with kernels.
>> But the toolstack (xend, xm, xentop etc.) gets overwritten.
>> So after trying out a new hypervisor, you have to reinstall
>> your old toolstack before booting in a older hypervisor.
>> 
>> 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.
>> 
>> --
>> Best regards,
>>  Sander                          mailto:linux@eikelenboom.it
>> 
>> 
>> _______________________________________________
>> Xen-devel mailing list
>> Xen-devel@lists.xensource.com
>> http://lists.xensource.com/xen-devel
>> 
> 
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@lists.xensource.com
> http://lists.xensource.com/xen-devel

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On 09/12/2009 00:23, "Sander Eikelenboom" <linux@eikelenboom.it>
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?

 -- Keir



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On Wednesday 09 December 2009 08:22:14 Keir Fraser
wrote:
> On 09/12/2009 00:23, "Sander Eikelenboom"
<linux@eikelenboom.it> 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@amd.com>


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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.

But i think it''s perhaps not worth the trouble and a bit ugly to make
that general, so just drop the idea :-)

--

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@eikelenboom.it> 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@amd.com>


-- 
Best regards,
 Sander                            mailto:linux@eikelenboom.it


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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@eikelenboom.it> 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@amd.com>


-- 
---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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Hi Christophe --

What is the earliest version of the tools for which this will work?
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!

Thanks,
Dan
> -----Original Message-----
> From: Christoph Egger [mailto:Christoph.Egger@amd.com]
> Sent: Wednesday, December 09, 2009 4:43 AM
> To: Sander Eikelenboom
> Cc: xen-devel@lists.xensource.com; 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@eikelenboom.it> 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@amd.com>
> 
> 
> 
> -- 
> ---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
> 
> 
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@lists.xensource.com
> http://lists.xensource.com/xen-devel
>
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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@amd.com]
> > Sent: Wednesday, December 09, 2009 4:43 AM
> > To: Sander Eikelenboom
> > Cc: xen-devel@lists.xensource.com; 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@eikelenboom.it> 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@amd.com>
> >
> > --
> > ---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
> >
> >
> > _______________________________________________
> > Xen-devel mailing list
> > Xen-devel@lists.xensource.com
> > http://lists.xensource.com/xen-devel


-- 
---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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Excellent!

I think it would be a great service for many developers if
you could clearly document all the steps on a Xen wiki
page.  Maybe start with:

"Assume you have a distro-supplied Xen with version < 4.0
installed on your machine and you wish to also build/install
either Xen 4.0 or xen-unstable PARALLEL to the distro
installation so that you can easily switch between the
distro version and the newer version.  Follow these steps..."

Thanks,
Dan
> -----Original Message-----
> From: Christoph Egger [mailto:Christoph.Egger@amd.com]
> Sent: Wednesday, December 09, 2009 9:57 AM
> To: Dan Magenheimer
> Cc: Sander Eikelenboom; xen-devel@lists.xensource.com; Keir Fraser
> Subject: Re: [Xen-devel] Re: is the xen toolstack backwards 
> compatible ?
> 
> 
> 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@amd.com]
> > > Sent: Wednesday, December 09, 2009 4:43 AM
> > > To: Sander Eikelenboom
> > > Cc: xen-devel@lists.xensource.com; 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@eikelenboom.it> 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@amd.com>
> > >
> > > --
> > > ---to satisfy European Law for business letters:
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> > >
> > >
> > > _______________________________________________
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> > > Xen-devel@lists.xensource.com
> > > http://lists.xensource.com/xen-devel
> 
> 
> 
> -- 
> ---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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