[TriLUG] Xen questions

[Jason Tower]

xen would be perfect for your needs.  your host OS (dom0 in xen terms) 
should run fc5 as it is very easy to get xen running.  you'll need 128-256mb 
for the dom0 plus whatever ram you want to allocate to each guest OS (domU 
in xen terms).

the hardest part is setting up the root filesystem for the domU, for centos 
you'd probably use yum with the --installroot=/some/path option (i think 
that's right).  you can either compile your own xenified centos kernel or 
use a stock fc5 domU kernel (i do the latter with my ubuntu domUs and it 
works fine).

the default network mode is bridge, so each domU will get its own ip address 
just like the dom0.  there are also nat and route modes but bridging is what 
98% of people want.

http://www.fedoraproject.org/wiki/FedoraXenQuickstart

jason

Owen Berry wrote:
> Some questions for those Xen and virtualization gurus out there. First,
> some background. I run Fedora Core 4 on my workstation, but a lot of
> what I develop ends up running on RHEL3/4 servers. Every now and then I
> have problems because of differences in Perl modules or packaging on the
> "production" machines. I suspect these problems will get worse over time
> as I'm "forced" to move to more recent versions of Fedora.
> 
> I'm wondering if I could improve my lot by using Xen to setup CentOS
> virtual hosts on my development machine, to more closely replicate the
> production machines. Xen appeals to me over other VM techniques
> because of it's low overhead - I have a decent workstation but it's
> still single CPU and 512M ram.
> 
> 1) Is this something that Xen would be good for?
> 2) Am I right in thinking that Xen would be a good virtualization
>    choice? I have a VMWare license, but I'm thinking it'll take too much
>    in the way of resources.
> 3) Sometimes people need to access my web server. Will I be able to
>    forward connections to a virtual machine, possibly using mod_proxy on
>    Apache. Or is there a more seemless way to do this? Not sure how
>    networking works in Xen, and assuming something similar to VMWare.
> 4) I'm thinking it would be beneficial to upgrade from FC4 to FC5 before
>    trying out Xen. Sound right?
> 
> BTW, I don't really want to convert my workstation to running CentOS so
> please don't suggest it, unless you feel you have to. :-)
> 
> TIA,
> Owen