RE: [Xen-users] Mixed DomU Architectures

["Petersson, Mats" <Mats.Petersson@xxxxxxx>]

> -----Original Message-----
> From: xen-users-bounces@xxxxxxxxxxxxxxxxxxx 
> [mailto:xen-users-bounces@xxxxxxxxxxxxxxxxxxx] On Behalf Of Dan Hawker
> Sent: 01 June 2006 04:21
> To: xen-users@xxxxxxxxxxxxxxxxxxx
> Subject: [Xen-users] Mixed DomU Architectures
> 
> Hi All,
> 
> Quick question that is slightly OT, but is Xen related.
> 
> Just got a new server thru the door and have a couple of questions.
> 
> Am running Xen 3.0.2 on it (dual Xeon HP server with 4GB 
> RAM). Runs like a charm. As its a new machine it came with 2x 
> EM64T Xeons. The Dom0 is a FC5
> x86_64 install. My DomUs are mostly FC4 i386 installs (I have 
> an i386 based container of FC4 I use as a template) that I 
> combine with the x86_64 DomU kernel that came with FC5.
> 
> As mentioned, works fine.
> 
> One of the key plans for this box is as a place for software 
> developers to compile/build etc, without nasty pieces of 
> software killing the box as a whole. The plan is one VM per 
> team of about 4.
> 
> My only stumbler is the fact that my VMs naturally announce themselves
> (uname) as x86_64 machines, however the target for the 
> software is i386 only. Now I know you can set the arch using 
> setarch (and this works as
> expected) however this only works on a command-by-command basis.
> 
> I have found out (by reading this list mostly) that you 
> cannot mix kernel architectures within Xen. ie you can't have 
> a x86_64 Dom0 kernel and mixed
> x86_64 and i386 DomUs, so I can't just install a pure 32bit 
> DomU for these dev VMs.
> 
> Does anyone know a way of setting setarch permanently (rather 
> than running it at every command) or someother cunning plan 
> so that when building, the dev VM will respond with a *i'm an 
> i386 machine* rather than an x86_64.

If you do "setarch i386 bash", you get a new shell that believes it's
architecture is i686. Anything started from that shell will see i686 as
the machine arch. 

So, if we assume you have logged-in users that work on these machines,
it would be easy to just create a bash-i386 script that is exectuable,
and contains "setarch i386 bash $0" [or something like that - I'm not a
bash programmer], and set bash-i386 to the login shell of the user(s). 

Now, this doesn't work for everything, but for users loggin in, it will.
If there are other places where you'd like to emulate this, then similar
things can be done, but solutions need to be based on what you need to
do. 

--
Mats
> 
> TIA
> 
> Dan
> 
> 
> 
> _______________________________________________
> 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