Supporting highly manageable Web services

This paper focuses on the management aspects of Web service provision. We argue that support for manageability has to be considered at the design stage if services are to be capable of delivering high levels of quality of service for their users. Examples of the problems caused by lack of manageability include maintenance operations that necessitate service downtime, or difficulties in ensuring consistency of information. We categorise management issues into those concerning a site as a whole and those pertaining to individual services. Our approach to site management supports the arbitrary distribution of services to machines, allowing the optimum cost/performance configuration to be selected. Services can be easily migrated between machines, resulting in sites that scale, both in terms of the number of services and the number of users. Service management issues may be generalised as supporting evolution, for example, supporting changes to the functionality, the presentation logic, and the overall look and feel of a service. Our approach, based on the separation of functionality and presentation, allows such changes to be performed on-line and ensures that updates are reflected consistency across the various pages of a service, or across services. This approach also facilitates the development of services that utilise dynamic content for service customisations, such as tailoring a service to match the profile of users. Furthermore, all management operations are available through Web-based interfaces, making them accessible to a broad range of users, not only specialist system administrators.