Supporting Coordinated Adaption in Networked Systems

Providing support for adaptive solutions that allow systems to change their behavior at runtime has the potential to improve functionality and performance in a variety of contexts. This paper argues that the true value of this approach can be realized only by addressing the issues needed to provide a general solution. These include supporting adaptations that span multiple hosts and multiple system components, and algorithmic adaptations that involve changing the underlying algorithms used by the system at runtime. In addition to elaborating on these issues, an overall software architecture that includes an adaptation controller and graceful adaptation protocol is described. The architecture is being implemented using Cactus, a system for constructing highly-configurable distributed services and protocols.