This document discusses cloud computing and the open source cloud platform OpenStack. It defines cloud computing and the different cloud service models - SaaS, PaaS, and IaaS. It then describes the components of OpenStack including Nova, Neutron, Swift, Cinder, Keystone, Glance, Ceilometer, and Heat. It provides an example architecture of a three node OpenStack deployment and discusses DevStack, an OpenStack development environment installation tool.