[nzlug] VMware x Xen x KVM x Qemu

[Papalagi Pakeha]

Hi guys,

I'm playing with virtualization to get a better understanding of the
many technologies now available for linux. And I wonder what are your
favourites and why?

So far I got these impressions:

VMware Server
+ installation is no brainer and the interface is very user friendly
- networking is magic, it creates some vmnet interfaces and does NAT
on them automagically which makes it hard to impossible to use
standard iptables NAT and stuff on it.
- vmware-tools don't install in Ubuntu Hardy but that could be because
my Hardy DVD the beta one.
- client sw is needed on the remote side but there's a linux version
so it's not that bad.

Xen in CentOS 5
+ comes bundled with the system - that's good for updates and support
- I couldn't make graphical console running over the network (got only
black screen) but works fine on the server locally. That makes it hard
to use on remote servers and also means that the server must have
X.org running.
- Win XP failed to install even though my CPU definitely has
virtualization support
- Networking is even more magic than in VMware and I couldn't figure
out how to put the VM on NAT, it was always bridged to eth0.

Qemu
+ Open Source
+ Standalone solution that runs everywhere
+ Networking is clearly designed - it uses eth bridges in a non-magic way
+ VNC support for console is a great idea
+ Can be managed from command line on the server
- Terribly slow
- By far the least user friendly from VMware and Xen for an average user

KVM (+ Qemu)
* I don't understand exactly what it does. Looks "just" like a
speed-booster for Qemu to me and most of the userspace things come
from Qemu. Is it something like a free implementation of kqemu module?
+ Speeds up Qemu to near-native speed.
- Seems to be in heavy development that makes the userspace changing
often (e.g. configuring the recent KVM according to howto written in
november last year didn't quite work).
Other +/- see Qemu

So far I'm undecided - all of these work nicely with Linux guests and
that's what I need. I haven't done any benchmarks and all of them look
reasonably comparable in speed.

Is there anything special and noteworthy about any of these
technologies? Do you have any good stories and bad stories to support
one one of them?

PaPa