At work we have Linux users who understandably prefer using Ubuntu. Problem is, we also have developer tools that only work with 'officially' supported Linux distributions that use much older 2.6.18 based kernels. (And even if they worked with newer ones, the vendors could always say they won't "support" the software unless it's on one of their 'officially' supported platforms.)

We could of course just tell them to use CentOS or something else 2.6.18-based, and I'm sure their response would be something like: "you can take Ubuntu from our cold, dead hands." :)

Which brings to me some questions--is there any good/easy/recommended way to run something like Ubuntu as a host VM and Centos 5.x as a guest OS (with which system--Xen,KVM,VMWare, ...?), and then roll that into our own custom internal distribution that could be easily installed?

KVM looks like a good high-performance option just recently included in RHEL 5.4, but if hardware support for virtualization like Intel-VT or AMD-V is necessary, then I'd guess only those folks with fairly new PCs will be able to do it.

Would be very interested to hear how anyone else has addressed this kind issue.

EDIT: The target audience / users of this kind of system would be developers, each one needs to run locally licensed commercial software, so building out some separate beefy central machines isn't an option unfortunately due to license restrictions. Even if that weren't the case, a couple developers could quickly eat up the resources with parallel builds. :)

Ideally, I was hoping there was some step-by-step guide out there to build your own pre-built distribution that had e.g. CentOS 5.x and Ubuntu Desktop as a guest.