OpenStack is an open source cloud computing platform that allows users to build private and public clouds. It provides infrastructure as a service (IaaS) and allows users to provision compute, storage, and networking resources on demand in a self-service manner. The document discusses the history and components of OpenStack, including Nova (compute), Swift (object storage), Cinder (block storage), Keystone (identity), Glance (image service), and others. It also covers OpenStack deployment models, supported hypervisors and images, and how to easily install OpenStack using PackStack.