Peter
A few days ago, I took a look at qemu as an open source virtualisation solution. I'm also hopefully going to take a look at Xen at some point.
However, there is also a relatively new free software virtualisation product, OpenVZ. Here's the official description:
OpenVZ is an Operating System-level server virtualization solution, built on Linux. OpenVZ creates isolated, secure virtual environments — VEs (otherwise known as virtual private servers, or VPSs) on a single physical server enabling better server utilization and ensuring that applications do not conflict. Each VE performs and executes exactly like a stand-alone server; VEs can be rebooted independently and have root access, users, IP addresses, memory, processes, files, applications, system libraries and configuration files. See Documentation » Technology for more information.
OpenVZ only runs on Linux and at the present time only supports Linux guest virtual machines as well. It's not too likely we'll see it be ported to other platforms, the technology is tied quite close to Linux architecture.
Its approach is very different to that of qemu and OpenVZ is much less focused on testing new operating systems out and running multiple different environments. Instead, it goes for the more enterprise approach of running multiple instances of one thing. In actual fact, you can run different Linux distributions (provided they use exactly the same kernel version), but that's not really the aim.
OpenVZ is extremely useful in an environment such as if you are a hosting provider and you want to offer customers complete control over their operating system (root access). This type of scenario is where OpenVZ really shines.
I haven't had a chance to give OpenVZ a spin myself, but it looks extremely promising and when I do have a chance I'll have a play around. If you're interested in the technology behind it, its Wikipedia page has some quite interesting stuff.
If you've used OpenVZ, what are your experiences? How does OpenVZ compare to solutions like Xen? Feel free to comment.
