Kirk Wilson

A Policy-Based Middleware for Web Services SLA Negotiation

Negotiation of Service Level Agreements (SLAs) is very important for maintaining Quality of Service (QoS) of composite Web services-based business processes. The process of negotiation involves specification of negotiation parameters, exchanging offers to conduct the actual negotiation process, and then finally generating the formal SLA if the negotiating parties come to a consensus. We propose a Negotiation Broker (NB) middleware framework to facilitate automated negotiations of SLAs for Web services in a Service Oriented Architecture (SOA). High level business goals, contexts, preferences, constraints, and values of the negotiation issues are expressed as a policy specification by each of the negotiating parties. The NB maps the policy specifications to low level negotiation strategy models and parameters in order to conduct the negotiation locally as a trusted broker. We present a model and an example of the high level negotiation policy specification. We also present our NB framework including a prototype implementation to illustrate the mapping of the policy to a time-dependent negotiation strategy model.

A Middleware Solution to Monitoring Composite Web Services-Based Processes

Web services can be composed to create complex business processes that span multiple organizations. quality of service (QoS) of such a process is guaranteed by a set of service level agreements (SLAs) between the service providers and the service consumers. Monitoring is required at every service provider and at the service consumer end in order to ensure satisfaction of the SLAs. Distributed monitoring of business processes can be complex and costly. We propose a middleware solution, namely the performance monitor (PM) framework, to enable outsourcing of the task of SLA monitoring of both intra and inter-organizational composite Web service processes. We present a prototype implementation of the PM with experimental data to establish the effectiveness of the framework in monitoring and verifying SLAs for a composite process and discuss possible extensions to the framework for more generalized applications.

The WSDM of Autonomic Computing: Experiences in Implementing Autonomic Web Services

There is a strong relationship between proposed frameworks for autonomic computing, such as the IBM blueprint for autonomic computing, and the Web services distributed management (WSDM) standard proposed by OASIS. We examine this relationship through a description of our efforts to implement an autonomic Web service using WSDM. The example autonomic Web service is based on our Autonomic Web Service Environment (AWSE) framework. We explain how WSDM is used to implement the AWSE components and evaluate the results of the exercise. We present the lessons we learned in carrying out the implementation effort and draw general conclusions concerning the relationship between autonomic computing and WSDM.

A model for dynamic and adaptable services management

The dynamic nature of Service-Oriented Architectures challenges traditional systems management practices which tend to be static in nature. We propose a goal-oriented, agent-based approach to management using autonomic computing. In this paper we define a services management model that consists of a number of constructs including managed resources, agents, events, event streams and management goal graphs. Agents accept new events on one or more event streams, and the arrival of an event triggers local processing that includes the generation of a new event and/or changes to the state of the managed system. Simple agents are combined into management goal graphs to carry out complex management tasks. We provide details of an implementation of our services management model and show how this model could be used in a sample management scenario.

A Sensor-Based Approach to Symptom Recognition for Autonomic Systems

The increased complexity of todays distributed, composite, Web-based systems presents difficult and unique systems management problems. The way these systems interact, and the fact that they often span organizational boundaries, render them difficult to monitor and manage. Autonomic Computing has emerged as a promising approach to the management of complex systems. A key to realizing fully autonomic systems is the development of monitoring tools that provide the controllers with adequate and meaningful performance information, especially the identification of symptoms that indicate potential underlying problems. We present an event- driven sensor approach to a monitoring system whereby a hierarchy of dedicated, simple sensors monitors and correlates low level events into a meaningful representation of the system performance that can be used for problem determination. Our approach utilizes the OASIS Web Services Distributed Management (WSDM) standards.