This is a step-by-step practical guide to get you started easily with openNebula. It guides you to build, maintain, and configure your cloud infrastructure, providing real-world examples in a simple and coherent manner. If you are a GNU/Linux system administrator with no experience with virtualization or cloud computing but eager to learn about it, or you are thwarted by your current virtualized infrastructure, this book is for you. You are expected to have some basic knowledge of GNU/Linux, with knowledge of basic package management tools and system configuration.