Autonomic Configuration Adaptation Based on Simulation-Generated State-Transition Models

Configuration management is a complex task, even for experienced system administrators, which makes self-managing systems a particularly desirable solution. This paper describes a novel contribution to self-managing systems, including an autonomic configuration self-optimization methodology. Our solution involves a systematic simulation method that develops a state-transition model of the behavior of a service-oriented system in terms of its configuration and performance. At run time, the system´s behavior is monitored and classified in one of the model states. If this state may lead to futures that violate service level agreements, the system configuration is changed toward a safer future state. Similarly, a satisfactory state that is over-provisioned may be transitioned to a more economical satisfactory state. Aside from the typical benefits of self-optimization, our approach includes an intuitive, explainable decision model, the ability to predict the future with some accuracy avoiding trial-and-error, offline training, and the ability to improve the model at run-time. We demonstrate this methodology in an experiment where Amazon EC2 instances are added and removed to handle changing request volumes to a real service-oriented application. We show that a knowledge base generated entirely in simulation can be used to make accurate changes to a real-world application.