Virtualisation technologies like KVM and Xen are very useful, as well as being open source and truly free, but they can be a little tricky to work with. Virtual Machine Manager provides a graphical front end to KVM, Xen and Qemu virtual machines. It can be used to create, run and manage VMs and includes wizards for the common tasks, like creating a new machine.

Virtual machines can be created from scratch in Virtual Machine Manager or they can be imported from existing files. It is also possible to set up a KVM virtual machine that uses an existing VMware disk file, making transferring virtual machines from VMware to KVM a trivial task. Virtual Machine Manager i also useful for monitoring virtual machines, with graphs showing processor, memory, and network usage letting you see which VMs are loading your system the most, and when.

Because this is just the GUI, the command line tools for the various virtualisation technologies it supports do much of the real work, it can be extended to cover other types of virtualisation should the need arise. This has already happened as it originally only supported Xen. A consistent interface for working with different types of virtual machine improves productivity and makes switching between types much simpler. If you have used VMware or VirtualBox products before, you will feel immediately at home using Virtual Machine Manager.