“Linux had always lacked a Open Source virtualisation technology in the same league as Solaris containers or commercial product like Vmware. That was until Xen came into the picture. Xen is an opensource virtual machine monitor for x86 that supports execution of multiple guest operating systems. Recently, I downloaded the Xen Live CD ISO image from their website and burned it on to a CD in order to give it a trial run. What follows below are my experiences in trying out this very promising virtualisation technology.”
The only problem I see with Xen is that it’s not as easy as VMware (well, that and Windows support on the current iteration). With VMware, it just makes *sense*. You create a VM with the web wizard, optionally assign an ISO image for the CD-ROM, and it acts just like a regular PC in a window.
Xen (admittedly, I didn’t delve too far into it and in the 2.0 time frame) wasn’t ‘easy’ like that. You have to find custom kernels or patched OSs (like FreeBSD), and I’m still unsure of how you actually ‘install’ the guest OS. I tried Xen in SLES10, and the VM failed to boot properly.
The test CD is fantastic, but it’s a canned world. As soon as you try to create your own setups, the learning curve gets steep.
I’m sure someday Xen will be made easy, but right now its more hassle than I’m willing to put into it.
Edited 2006-10-16 15:34
Disclaimer: I work on Xen, am paid by XenSource.
Xen is getting easier. There have been a few attempts at a web interface but none have really stuck in the free product. There’s one in the commercial product XenEnterprise, however.
Distro integration should make things easier. Novell SLES, etc can install Xen by default and include a Yast Module for installing further virtual machines (currently only SuSE VMs are supported, I think, with support for others planned for future releases of their enterprise products).
RedHat are doing similar stuff with the next RHEL release, and their VirtManager software (which will also manage virtual machines on other virtualisation / emulation platforms such as QEmu, allowing users more flexibility).
Distro integration is definitely the next step. I’m happily using Xen on my Debian systems and with my xen-tools I can create a new instance of Debian, CentOS, or even Gentoo in just a few minutes.
http://xen-tools.org/
The web/console control panel does need to be written yet. There have been several started but none have gained significant traction, and it is a hard problem to solve. (Mine I gave up on; it’ll come back once I’ve planned the spec more.)
Kudos to the entire Xen team for such cool and easy to use technology though.
Who in their right mind would think that a machine with only 256MB of ram would be a good candidate for virtualization?
After I read that part and seeing the guy try to run gnome I just skirted the article, it didn’t seem to be worth wasting time reading it.
From the article…
“Needs a good amount of memory for it to be of any use to anybody. I would recommend atleast 1 GB memory even though with a little bit of tweaking like I did above, you might be able to use it with less than 256 MB RAM. Though its practical use will be limited.”