Architectural Styles for Adaptable Self-Healing Dependable Systems

Of all the possible architectural approaches to improving the dependability of software-based systems, only systems designed to be self-healing are able to adapt themselves at runtime in response to changing environmental or operational circumstances. In this paper, we discuss the basic functional requirements for self-healing systems, and explore a number of major issues related to architectural designs for incorporating runtime reflection and adaptation into software systems. We present several conceptual architectures for self-adaptation, and analyze the features, advantages and disadvantages of each architecture. Finally, we propose enhancements to currently used architectural description languages (ADLs) and system design tools to add explicit support for self-adaptive architectures.