Cloud Computing Architecture

As a general model for delivering Information Technology services, cloud computing has broad applicability for adopters with diverse needs. For instance, some cloud advocates have argued that virtualization is a necessary technology component of cloud computing, whereas others argue that it is not always necessary. Likewise, some advocates claim that multitenancy is a necessary cloud capability, and yet in some cloud implementations, multitenancy is not available. This chapter examines cloud computing and offers additional perspectives to better explain what it constitutes. It begins by presenting the NIST Cloud Computing Model and revisits the essential characteristics of clouds, dissecting the three cloud services models along with the four cloud delivery models. Next, it looks at the relative degree of control a tenant or consumer has with the different models. Finally, the chapter explores the models from a different set of perspectives, culminating in a discussion of how clouds are formed and used.