This document discusses building your own cloud using the open source technologies GlusterFS and OpenStack. GlusterFS allows using unused disk space across multiple servers as a distributed file system, providing scalability and high availability. OpenStack provides an open source platform for managing infrastructure resources like compute, storage, and networking, allowing you to build your own private or public cloud. The document provides examples of infrastructure as a service (IaaS), platform as a service (PaaS), and software as a service (SaaS) cloud models and how GlusterFS and OpenStack can be used to offer these services using commodity hardware.