WP-JRA-2.3

PO-JRA-2.3.1 Use Case Description and State-of-the-Art — by Andreas Gehlert — last modified May 19, 2009 10:12

The aim of this document is to introduce the most important aspects and the state-of-the-art of self-* infrastructures and service registry, binding and invocation. The property commonly referred as self-* is a collection of one or more reflexive properties expressing the ability of changing some aspects of the working behaviour of a computing entity. They are surveyed as self-optimisation and self-healing in a numerical simulation example; autonomic brokering; dynamic self-deployment of services; dynamic adaptation, self-optimisation, self-healing and self-configuration in a mobile environment. Software systems built on top of Service-Oriented Architectures (SOA) use a triangle of the three operations "publish", and "bind" in order to decouple the participants in the system. Key elements of the survey are Service Discovery (centralised vs. distributed, keyword-based, signature-based, semantics-based and context-based approaches), QoS-based service discovery, Dynamic Binding and Dynamic Invocation.

CD-JRA-2.3.2 Basic Requirements for Self-Healing Services and Decision Support for Local Adaptation — by Benedikt Liegener — last modified May 19, 2009 10:12

One of the goals of S-Cube is to look for general solutions by integrating research agendas from diverse research areas, such as business processes, service-oriented and grid computing. The world of web services already provides solutions for complex user tasks. The web service model is based on three actors: a service provider, a service requester and a service broker. There are also well established and widely used technologies that enhance the collaboration of these three parties to fulfil service executions required by users. The newly emerging demands of users and researchers call for expanding this service model with business-oriented utilization (agreement handling), support for human-provided and computation-intensive services. This evolution also affects the service infrastructure; new components appear that need to provide self-* operation. The purpose of this document is to capture the basic requirements for self-healing and decision support in service execution, deployment and runtime management for services including core services such as discovery and registries. Concerning service execution, we describe what kind of functionalities and tools should be provided at the infrastructure level in order to be able to implement a self-healing service. We restrict the scope of this document to the adaption of one service, not of a coordinated set of services. Concerning deployment and run-time management, we envision a conceptual architecture for SLA-based on-demand service provisioning and, based on this framework, three main functionalities are separated: negotiation, brokering and deployment. The document investigates the requirements in details for each of these fields. This document mainly addresses Threads C1 and C2 of the WP 2.3 research architecture and partly applies to A1 and B1. See also the companion deliverable CD-JRA-2.3.3 which addresses service discovery and registries (Thread A2, A3, B2 and B3). C3 will be addressed in deliverable CD-JRA-2.3.8.

CD-JRA-2.3.3 Requirements for Service Registries in Dynamic Environments and Evaluation of Existing Service Registries — by Benedikt Liegener — last modified May 19, 2009 10:13

Web service registries are tools for the implementation of loosely-coupled service-based systems. For instance, business processes query registries in order to find services which implement functionality that is needed in the process, and adaptable service compositions need to be aware of which alternatives are available for each service. Furthermore, there is a clear interrelation between end-to-end quality provisioning and monitoring, and service registries, since SLA monitoring and enforcement is based on the availability of a service repository providing an expressive set of metadata. Even more, with the advent of the Internet of Services, an Internet-scale Web service ecosystem with unique scale and heterogeneity characteristics, a number of new challenges for the next generation of Web service registries will arise. First of all, the sheer size of the ecosystem (in terms of number of clients, providers and services) will cause a need for new scalable service discovery mechanisms built on the notions of the Internet. This includes not only discovery of atomic services, but also of task flows (ad hoc service mashups). Additionally, the distributed and heterogeneous nature of the Internet of Services asks for new data dissemination methods between physically and logically disjoint registry entities, which work in spite of missing, untrusted, inconsistent and wrong data. Further challenging requirements are going to be put forward by mobile, human-provided and ad hoc services, which are common in the Internet of Services. These services are volatile in nature, and need to be actively tracked by the service registries. Finally, another class of challenges is introduced by the human factor in the Internet of Services -- since services are often consumed and provided by humans, new means of evaluating service performance based on user-perceived and fuzzy Quality of Experience metrics need to be devised. In this deliverable we describe these requirements for the next generation of service registries for large-scale service environments in detail, and explain why we consider existing registry approaches as not sufficient for these environments. The deliverable provides the baseline research topics to be covered by the ``registry segment'' of the work package WP-JRA-2.3 in S-Cube; research questions steering the second part of the work package focussing on adaptation are described within the deliverable CD-JRA-2.3.2.

CD-JRA-2.3.4 Decision Support for Local Adaptation — by Osama Sammodi — last modified May 17, 2010 16:09

This deliverable is aimed at summarizing the joint research in WP-JRA-2.3. related to decision support for local adaptation. It is an intermediate stage on the research roadmap, starting from issues of local adaptation and self-healing (CD-JRA-2.3.2) to the most complex case involving distributed multi-level adaptation (CD-JRA-2.3.8), where we investigate and integrate certain methods and techniques incrementally. The work is based on and motivated by the antecedent deliverable ''Basic requirements for self-healing services and decision support for local adaptation'' (CD-JRA-2.3.2) and is focused on local adaptation and decision which we consider one of the most important ways to investigate the applicability of certain policies to trigger local adaptation mechanism, and is organized around the general adaptation framework introduced in CD-JRA-2.3.2. Results are presented in 10 published papers that constitute the core contribution of this deliverable. The work is positioned within the Integrated Research Framework (IRF, WP-IA-3.1), internal WP-JRA-2.3 research architecture and overall WP-JRA-2.3 goals and visions.