This book covers Xen—an open-source paravirtualization technology that provides a platform for running multiple operating systems on one physical hardware resource, while providing close to native performance. Xen supports several operating systems—Linux, FreeBSD, Windows, and NetBSD. It was originally developed in 2003 at the University of Cambridge Computer Laboratory and now both commercial and free versions of the Xen hypervisor are available. The commercial versions are built on top of the open-source version and have additional enterprise features. In this book we explore and use the open-source version of Xen. Each chapter in this book is a collection of practical tasks that demonstrates how to achieve common virtualization tasks—you then learn how it works so that you can apply this knowledge to your Xen installation and environment.