Thursday, 10:30 AM – 12:00 PM
Chairs: Peep Kungas

Selecting Skyline Services for QoS-based Web Service Composition

Mohammad Alrifai, Dimitrios Skoutas, Thomas Risse

Web service composition enables seamless and dynamic integration of business applications on the web. The performance of the composed application is determined by the performance of the involved web services. Therefore, non-functional, quality of service (QoS) aspects (e.g. response time, availability, etc.) are crucial for selecting the web services to take part in the composition. The problem of identifying the best candidate web services from a set of functionally-equivalent services is a multi-criteria decision making problem. The selected services should optimize the overall QoS of the composed application, while satisfying all the constraints specified by the client on individual QoS parameters. In this paper, we propose an approach based on the notion of skyline to effectively and efficiently select services for composition, reducing the number of candidate services to be considered. We also discuss how a provider can improve its service to become more competitive and increase its potential of being included in composite applications. We evaluate our approach experimentally using both real and synthetically generated data sets.

Automated Performance Assessment for Service-Oriented Middleware

Domenico Bianculli, Walter Binder, Mauro Luigi Drago

Middleware for Web service compositions, such as BPEL engines, provides the execution environment for services as well as additional functionalities, such as monitoring and self-tuning. Given its role in service provisioning, it is very important to assess the performance of middleware in the context of a SOA. This paper presents SOABench, a framework for the automatic generation and execution of testbeds for benchmarking middleware for composite Web services and for assessing the performance of existing SOA infrastructures. SOABench defines a testbed model characterized by the composite services to execute, the workload to generate, the deployment configuration to use, the performance metrics to gather, the data analyses to perform on them, and the reports to produce. We have validated SOABench by benchmarking the performance of different BPEL engines.

Autonomous Resource Provisioning for Multi-Service Web Applications

Dejun Jiang, Guillaume Pierre, Chihung Chi

Dynamic resource provisioning aims at maintaining the end-to-end response time of a web application within a pre-defined SLA. Although the topic has been well studied for monolithic applications, provisioning resources for applications composed of multiple services remains a challenge. When the SLA is violated, one must decide which service(s) should be reprovisioned for optimal effect. We propose to assign an SLA only to the front-end service. Other services are not given any particular response time objectives. Services are autonomously responsible for their own provisioning operations and collaboratively negotiate performance objectives with each other to decide the provisioning service(s). We demonstrate through extensive experiments that our system can add/remove/shift both servers and caches within an entire multi-service application under varying workloads to meet the SLA target and improve resource utilization.


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