Stuart Herbert | Gentoo

One of the most talked about opensource projects of the year is Xen, the hypervisor-based virtual machine technology from the University of Cambridge. I’m very interested in Xen - it’s an interesting technology for with a lot of potential for server and service provisioning - but I’ve been too busy with other things to have a play.

Having gone through Xen-2.0.6 (w/ kernel 2.6.11), Xen-2.0.7 (w/ kernel 2.6.11), Xen-2.0-testing (w/ kernel 2.6.12.5), and Xen-unstable (w/ kernel 2.6.12.5), my experience is that “vanilla” Xen still has a few problems to iron out.

Of the four that I tried, Xen-2.0.6, Xen-2.0.7 and Xen-2.0-testing all compiled without any hitch - but none of them would boot. They all paniced during the kernel’s boot process, and then promptly rebooted before I could read the screen or capture the details. It took a bit of time to figure out how to capture the crashes. Thanks to VMware Workstation, I now have AVI videos of the boot sequence, showing the panics.

Xen-unstable (the code that will become Xen 3.0) doesn’t build. The xenbus driver relies on a header file which doesn’t exist within the kernel tree - xenstored.h. It’s included in the tools directory of the xen utilities; for now I just put a copy into drivers/xen/xenbus and rebuilt the kernel. There’s a patch posted on the xen-devel mailing list for anyone who uses mkbuildtree.

The good news is that xen-unstable does boot. The machine’s console doesn’t work; I have to ssh into the machine to use it. This evening’s task is to try and get an unprivileged domain up and running.

But first I need to recompile glibc; mine was built with USE=nptlonly, which slows Xen down.