This chapter provides an overview of cloud-based information technology (IT) infrastructure. It introduces cloud computing concepts such as public cloud, private cloud, and hybrid cloud. Also, it explains cloud services such as infrastructure as a service (IaaS), platform as a service (PaaS), and software as a service (SaaS). The chapter describes the cloud architecture, which illustrates how the cloud is constructed and how the hardware and software are used in supporting cloud computing. For better flexibility and scalability, cloud services are provided through the virtualized IT infrastructure. The chapter also describes how the virtualized IT infrastructure works and how it can be used to provide cloud services. As an overview, the chapter moves through the development process to create a cloud infrastructure. It explains how to conduct the requirement analysis, how to select the hardware and software, and how to specify the hardware and software to support the IT infrastructure to implement cloud services.