Cloud Computing Applications

Abstract

Cloud computing focuses on elasticity, i.e., providing constant quality of service independent of workload. For achieving elasticity, cloud computing applications utilize virtualized infrastructures, distributed platforms, and other software-as-a-service offerings. The surge of cloud computing applications responds to the ability of cloud computing environments to only pay for utilized resources while saving upfront costs (e.g., buying and setting up infrastructure) and allowing for dynamic allocation of resources even in public-private hybrid scenarios.This chapter investigates the shift from classical three-tier web applications to such elastic cloud computing applications. After characterizing web applications, we describe cloud computing characteristics and derive how web applications can exploit these characteristics.Our results motivate novel requirements that have to be engineered and modeled, as further described in this chapter.

The remainder of this chapter is structured as follows. Section 3.1 gives a high-level overview of views and aspects important for cloud computing applications. Afterward, Sect. 3.2 details characteristics of web applications, and Sect. 3.3, those of cloud computing. Section 3.4 outlines how web applications can be moved to cloud computing applications by exploiting cloud computing characteristics. Based on these insights, we derive novel requirements for cloud computing applications in Sect. 3.5 and show how to appropriately model cloud computing applications to analyze such requirements in Sect. 3.6. Section 3.7 refines our running example—CloudStore—to a cloud computing application. Subsequently, Sect. 3.8 highlights some hints for modeling such applications.