Service Level Agreements for the D-Grid

Einordnung bezüglich D-Grid

Goals and Services of the Proposal
The SLA4D-Grid Project is engaged in the design and realisation of a Service Level Agreement layer (SLA layer) for the D-Grid. This layer is situated, as shown in the illustration, between the D-Grid middleware (gLite, Globus, UNICORE) and the D-Grid user layer and will be integrated into the existing D-Grid infrastructure (e.g. through connections to core D-Grid services). Communities may either use the SLA layer via SLA-enabled clients or through direct interfaces. The SLA layer is a value-added service and does not interfere with the present use of the D-Grid, nor does it require changes in communities that do not yet have a need for SLAs, thus allowing for a seamless transferral of the results from the SLA4D-Grid into regular operations.

The Service Level Agreement layer offers individual users, whole D-Grid communities, and the providers of D-Grid resources service usage under given guarantees, quality-of-service requirements and pre-defined business conditions. For this purpose, service level requests and the corresponding offers are linked by binding Service Level Agreements. By means of the SLA layer and with the assistance of other D-Grid services, such as monitoring and accounting, SLAs can be automatically created, negotiated and their observance monitored, so that the D-Grid can be used by academic and industrial users in an economically efficient manner, in accordance with their respective business models.

Usage Scenarios
The fundamental use case for which support is provided by virtue of the definition of a generic D-Grid SLA is the provision and use of D-Grid computing resources governed by economic constraints. This general use case will be evaluated and expanded using the commercial scenarios provided by Sun Microsystems and con terra GmbH. Furthermore, the following usage scenarios will be considered in relation to Service Level Agreements and supported by the SLA layer.

Business Model Support (L3)
The implementation of SLAs in the D-Grid allows the communities to realise new business models by concluding and deploying framework agreements. The accounting of services or e-Business scenarios is included here, among other applications. In this context, further work will be based on procedures and services developed in the D-Grid which are already in use.

Planning and Reservation of D-Grid Resources (L3)
In order to use resources economically, it is necessary to provide planning and reservation tools. The SLA layer offers interfaces for using, for example, scheduling services in the D-Grid, such as those being realised in the DGSI Project (D-Grid Scheduler Interoperability). The SLA layer provides general and generic negotiation protocols, which can be used by other services for the implementation of actual negotiations.

Mapping of Service Level Guarantees (L3)
Service level guarantees (Quality of Service (QoS) guarantees) are required by a range of usage scenarios. SLA4D-Grid ensures that these are mapped to SLAs and negotiated over the SLA layer, while offering the necessary monitoring services.

Advanced Security Scenarios (L3)
It is often necessary to make decisions over and above pure authorisation regarding which users have access to what services or data. These decisions may be based on roles and taken in accordance with detailed scales, sometimes after the acceptance of certain terms of use. SLA4D-Grid provides a framework based on the operational concept of the D-Grid and enables the realisation of such scenarios by using framework agreements and quality of service guarantees.

In order to support the needs of D-Grid users on the SLA layer, the relevant D-Grid communities and IT service providers are included in the requirement analysis for the SLA4D-Grid project. The goal is to keep the SLA layer generic, so that future communities can use it, but also to show direct benefit for specific use case for selected reference communities. For this purpose, communities are directly integrated into the project. Additionally, the partners contribute their expertise drawn from other projects in order to cover complementary requirements, thereby incorporating further communities. In order to determine the different requirements of the different groups, SLA4D-Grid will organise a series of workshops with IT service providers and D-Grid communities. The SLA layer is a value-added service that allows D-Grid users to realise novel business models previously impossible to implement. Service Level Agreements facilitate the economic use of services and resources. SLA4D-Grid creates a corresponding foundation by defining a generic, expandable D-Grid SLA layer, while incorporating IT service providers and the D-Grid community. The SLA layer will be executed as a decentralised service, corresponding to the needs of the D-Grid and D-Grid communities. The use of the service is generally transparent for the user, however to meet the particular needs of some communities, interfaces will be created to allow the service to be used directly. Additionally, value is placed on the closest possible integration into the D-Grid infrastructure, and attention paid to a seamless transition to regular operations. In the realisation of the SLA layer, standards are being applied wherever possible. Especially to note is the support of WS Agreement, the SLA standard from the Open Grid Forum, to which several of the partners in this project have actively contributed and will continue to play a leading role in its further development. Additionally, SLA4D-Grid will be oriented toward the work on WS-Agreement Negotiation and OGSA Resource Selection Service. Wherever possible, SLA4D-Grid relies on the middleware provided and existing D-Grid services and supplements them as an integral component of the future D-Grid.