Some of the amazing team at Joyent ported KVM onto the Illumos kernel.
Then, they went on to contribute their work to Illumos.
Finally, they've set up smartos.org, with the entire source code available at github.
What this means:
- An alternative to VMWare, Xen and KVM on Linux, where you now have the Illumos kernel (a fork of the opensolaris) powering your OS level virtualization.
- If it's just ruby/Python/Java/PHP apps you're running, then these can run within a Zone - you need not necessarily have a full blown OS to run your apps.
- You get the benefits of DTrace to trace performance. With KVM based guest OS, you can trace all manner of performance and resource utilization of the VM instance using DTrace.
- High speed VM setups. With ZFS clones, you'll be able to set up Windows VMs at a very high speed. (I've not done this with KVM on Illumos, but I have done this with Xen on OpenSolaris, as well as with ZFS-iSCSI, so I know that this works out very well).
- As per the FAQ, it'll be possible to use the OpenStack infrastructure to manage SmartOS too. This is something that I hope to try out real soon !
All in all, very exciting times ahead !