Towards dynamic service level agreement negotiation: An approach based on WS-agreement

In Grid, e-Science and e-Business environments Service Level Agreements (SLAs) are often used to establish frameworks for the delivery of services between service providers and the home organisations of the customers. While this high level SLAs, e.g. framework contracts, govern the relationship between the parties, it is desirable for the end-user to have dedicated quality of service (QoS) also for individual services like the orchestration of resources necessary for composed services. Grid level scheduling services typically are responsible for the orchestration and coordination of resources in the Grid, which requires the Grid level scheduler to coordinate resource management systems probably located in different domains. As the site autonomy has to be respected negotiating with the individual sites is the only way to achieve the intended coordination. Electronic SLAs emerged as a new way to negotiate and manage usage of resources in the Grid and are already adopted by a number of management systems. Therefore, it is natural to look for ways to adopt SLAs for Grid level scheduling. To realise this approach we need efficient and flexible protocols supporting dynamic negotiation and creation of SLAs. In this paper we propose and discuss ongoing work on extensions to the WS-Agreement protocol addressing these issues