This document provides an overview of OpenStack, an open source cloud computing platform. It discusses the history and origins of OpenStack at NASA and Rackspace, describes some of the core components including Nova (compute), Swift (object storage), Glance (image service), Cinder (block storage), Quantum/Neutron (networking), Keystone (identity), and Dashboard (web UI). It also outlines some key features of these components such as distributed architecture, API access, security groups, floating IPs, and pluggable networking backends. Finally, it encourages contributions to the OpenStack community through coding, documentation, translation, and other assistance.