Automatic configuration and run-time adaptation of distributed applications

Increased platform heterogeneity and varying resource availability, in distributed systems motivates the design of resource-aware applications, which ensure a desired performance level by continuously adapting their behavior to changing resource characteristics. In this paper we describe an application-independent adaptation framework that simplifies the design of resource-aware applications. This framework eliminates the need for adaptation decisions to be explicitly programmed into the application by relying on two novel components: (1) a tunability interface, which exposes adaptation choices in the form of alternate application configurations while encapsulating core application functionality; and (2) a virtual execution environment, which emulates application execution under diverse resource availability, enabling off-line collection of information about resulting behavior: Together these components permit automatic run-time decisions on when to adapt by continuously monitoring resource conditions and application progress, min how to adapt by dynamically choosing an application configuration most appropriate for the prescribed user-preference. We evaluate the framework using an interactive distributed image visualization application. The framework permits automatic adaptation to changes in CPU load and network bandwidth by choosing a different compression algorithm or controlling the image transmission sequence so as to satisfy user preferences of visualization quality and timeliness.