Aspect-oriented programming in the development of service-levels controllers of cloud applications

Service levels of a cloud application are application-specific. Mechanisms for delivering and controlling service levels should hence be defined at the same abstraction level as the application itself. In an implementation, this results in an interweaving combination of application logic and service-levels control mechanisms. The application is thus difficult to understand and maintain, i.e., has a low quality. In this paper, we argue that delivering service levels of a cloud application needs a feedback control system. This control system measures system outputs and adjust the system control inputs accordingly, in order to achieve the agreed service levels. Three models of control systems for service levels are identified, i.e., dedicated controller, shared controller, and shared application and controller. This paper investigates an approach to the use of aspect-oriented programming (AOP) in the development of service-levels controllers of cloud applications. In this approach, service-level mechanisms are considered as an aspect of cloud applications that are implemented separately from the application´s functional logic. As a result, the application can be expected to have a higher quality.