Observability and controllability of autonomic computing systems for composed Web services

Abstract

Autonomic Computing is a research area whose aim is to embed “intelligent algorithms” in the IT infrastructure management software such that it can adapt to changes in regards to the configuration, provisioning, external attacks, and resource utilization variations at run time. It is therefore, almost natural to consider this IT infrastructure control software framework as being designed upon methods and technologies used for the design of control systems. In this paper the control system design methodology is extended to the analysis of the intrinsic properties of the autonomic system itself. Thus the controllability and observability properties of the computing process itself are defined and examined in more details. These properties are also investigated for the case of cloud services where the serial and parallel composition of these services is considered. These cloud based services are connected through cooperation protocols that define a global process dynamic. Web services are modeled as scheduled computational processes waiting in a queue to cooperate in delivering the service. This paper proposes an input-state-output mathematical model for the autonomic computing model of cloud based services and the observability and controllability are further analyzed on the above models. As an example a Kalman based control is applied to such processes and the general architecture and some simulation results are given.