[KLUG Members] XEN-initial impression vs. UML

[Robert V. Kanaley]

Hey all,

Let me preface my remarks by saying I have never done any serious work with
UML, but I have played around with a couple of versions of UML. I just now
had a chance to bounce over to the Xen web site for a quick look.  I
immediately noticed a couple of differences. It appears that the Xen
approach requires the initial installation of the Xen environment that can
then host a Xen modified linux kernel. UML uses a UML modified linux kernel
to run on top of a normal linux kernel. The UML modified kernel process
creates what appears to the host system as a single large file. The UML
kernel uses this disk space as a container to hold the entire virtual
machine. Hence, the UML VM can host it's own file systems, and network.

The UML approach enables some interesting possibilities. For example, an
entire VM can be physically moved from one machine to another, an entire UML
session can be completely encrypted by running a VPN inside the VM. This
allows the entire VM session to be secured from other users of the same
machine, the LAN and the Internet. Lots of other interesting possibilities
that sparked my interest. Not sure how any of this would work with Xen.

Regards,

Bob

Robert V. Kanaley
Manager Information Systems
Agdia, Inc.
rvk at agdia.com
http://www.agdia.com

-----Original Message-----
There was some discussion of User Mode Linux not long ago as an
alternative to VMWare. This looks interesting too, and it is supposed to
ship with the next version of SuSE 9.3 in April.

http://www.cl.cam.ac.uk/Research/SRG/netos/xen/