I have an Ubuntu 8.04 (Hardy Heron) host machine which is running a whole slew of virtual machines in VMWare Server 1.0.8. Among other guest OSes, there is every release version of Ubuntu since 6.06, OpenSolaris 2009.06, and Windows XP. Right now I access these VMs from a variety of client OSes as well; Linux and Windows via the VMWare server console, and MacOS via X-forwarding the host machine's server console.

I'd like to upgrade the host to Ubuntu 10.04 (Lucid Lynx), but from what I can tell, getting VMWare Server 1.x to work on a more recent version of Linux is a real pain. While VMware Server 2.x is a bit easier, it's still not packaged as Debian packages, so installing security updates is a big chore. As long as I'm upgrading anyway, I'd like to move to a virtualization solution that will allow me to automate applying updates.

The options that I'm aware of right now are KVM (managed via virt-manager) and VirtualBox (as managed by its own tools or via its own libvirt bindings), but I'm open to other suggestions.

For each option, I'd like to know

• how do I convert my guest images to the new format?
• am I going to have to re-activate my Windows guests (alternatively, "If the virtual hardware is different by default, can I avoid re-activation by changing some virtualization configuration to provide me with more similar virtual hardware")
• what are the management options like for each client OS (mac, linux, windows)?

Thanks.