Re: [Xen-users] ideal xen setup?

[Mark Williamson <mark.williamson@xxxxxxxxxxxx>]

> >> If you could go with any distro for a DomU and tweak it in any
> >> way you like, what would be your idea setup for hosting
> >> virtual machines?

I've had generally quite good experiences with CentOS (and therefore I'd 
suggest RHEL is likely to provide similar results).  CentOS 5.1 comes with 
Xen 3.1 (although the package is named 3.0.3, it's lying).  The virt-manager 
tool has its quirks and can sometimes get a bit confused, however I've mostly 
found it was very good for creating and managing virtual machines.  Its 
ability to kick off a paravirt install of recent CentOS / RHEL / Fedora 
distros, downloading packages from the internet, is rather handy.

> You could use 'debootstrap' for .deb based distros or was it 'rpmstrap' or
> something to build .rpm based distros.
> And if your hardware support you can install much more with HVM.
> (and maybe after install move it to paravirt environment...)

I've had success installing Ubuntu under HVM and then converting to paravirt.

> That's true.
> 'Best Setup' depends so much what you are tying to accomplish.

For the record, my setup is a hacking / development setup.  Needs to be 
reasonably reliable but I cope with the downtime and complexity of 
occasionally having to fix things when they break.  Equally, some / many of 
the breakages are probably my fault!

> > Best overall supported, but without latest Linux kernel, is of course
> > from source (or a binary release) using the XEN 2.6.18 kernel (or the one
> > that is currently directly supported by the Xen Source software group)
> > from xen.org.

Best supported in terms of recent Xen features and the stability thereof, 
perhaps.

But the binary packages from XenSource are recommended only as a preview or as 
something for distributors to base their own packages on.  They're not 
recommended for production use because the packaging isn't as well integrated 
as a distributor can do, and because security updates will not be pushed out 
regularly like a distributor can do.  Basically, for a production system you 
do want a distro-provided kernel, where you get these things automatically.

Similar caveats for the source code: it's not intended to be always updated 
with upstream Linux security fixes, nor is it designed to integrate closely 
into your distro like a proper package would.

> > Things will get much better once all domU support has been merged into
> > the mainline Linux kernel. Has anyone heard about a serious push on
> > paravirt_ops and the like from any of the major players (RedHat, Novell,
> > IBM, Citrix, etc.) that would get full domU Xen support? I know Jeremy
> > called for it at the last Xen summit, I wonder if companies are taking
> > action?

Well.  You probably know that basic domU support has been in kernel.org's 
Linux since 2.6.23.  This includes block and net device drivers, SMP but not 
virtual framebuffer or live migration / suspend-resume support.

Work is underway on a paravirt_ops implementation of dom0 support.  The idea 
is that a paravirt_ops implementation will eventually be available so that a 
kernel can run either on bare metal, Xen dom0 or Xen domU.  It may be 
possible to merge dom0 support into mainline kernel.org Linux as part of 
paravirt_ops.

Even if that support isn't merged upstream, the patch that the XenSource folks 
have to maintain will be a much smaller patch due to Xen domU support already 
being in mainline.  This makes life easier for them and easier for 
distributors, giving them time to concentrate on other things.

The Fedora developers doing Xen packages (who I think are mostly or maybe all 
Redhat people) have decided to concentrate on improving the functionality of 
paravirt_ops and helping get more paravirt_ops stuff upstream in mainline 
Linux.  This is so that they don't have to keep forward-porting the Xen 
patches to newer kernels.  In the long term, that should help everybody.

> This is something what i can't understunt.
> What's the point to get support for DomU if you can't run Dom0? :)

Heh :-)  It'd be good to have newer dom0 for hardware support reasons.  But 
domU support was easier to get into kernel.org Linux, and most of the domU 
support stuff is also necessary for dom0 support to work.  Getting domU stuff 
into kernel.org is a first step towards this and means that the patch adding 
dom0 functionality to a normal kernel can eventually get smaller.


Hope that helps some,

Cheers,
Mark


> Im just asking cos I have Quad-Core with ICH9 based motherboard and that
> setup is newer going to work stable with 2.6.18....
>
> My life would be so much easier if Xen could be ported to mainline and
> would be 'only way' to run Linux :)
>
> My desktop setup now has 2.6.18-xen and all nice 3D-shit including Compiz
> and it's working like charm :)
> So I can 'boot up' pretty much anykind of testing environment i ever
> wanted and that's is pretty much all I need at home and work.
>
> Regards,
> Kalle
>
> > I would like to hear what others recommend too.
> >
> > Best Regards,
> > Todd
> >
> >> _______________________________________________
> >> Xen-users mailing list
> >> Xen-users@xxxxxxxxxxxxxxxxxxx
> >> http://lists.xensource.com/xen-users
>
> _______________________________________________
> Xen-users mailing list
> Xen-users@xxxxxxxxxxxxxxxxxxx
> http://lists.xensource.com/xen-users



-- 
Push Me Pull You - Distributed SCM tool (http://www.cl.cam.ac.uk/~maw48/pmpu/)

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