Service Level Agreement (SLA) in Utility Computing Systems (1010.2881v1)

Abstract: In recent years, extensive research has been conducted in the area of Service Level Agreement (SLA) for utility computing systems. An SLA is a formal contract used to guarantee that consumers' service quality expectation can be achieved. In utility computing systems, the level of customer satisfaction is crucial, making SLAs significantly important in these environments. Fundamental issue is the management of SLAs, including SLA autonomy management or trade off among multiple Quality of Service (QoS) parameters. Many SLA languages and frameworks have been developed as solutions; however, there is no overall classification for these extensive works. Therefore, the aim of this chapter is to present a comprehensive survey of how SLAs are created, managed and used in utility computing environment. We discuss existing use cases from Grid and Cloud computing systems to identify the level of SLA realization in state-of-art systems and emerging challenges for future research.

• The paper presents a comprehensive survey of the SLA lifecycle in both Grid and Cloud computing systems.
• It identifies and analyzes challenges like provider discovery, negotiation complexities, and automated monitoring to ensure QoS.
• It outlines future research directions for enhancing scalability, dynamic management, and cross-domain interoperability in utility computing.

An Overview of Service Level Agreements in Utility Computing Systems

The paper "Service Level Agreement (SLA) in Utility Computing Systems" by Linlin Wu and Rajkumar Buyya offers a comprehensive survey on the creation, management, and utilization of Service Level Agreements (SLAs) within utility computing environments, including Grid and Cloud computing systems. As a cornerstone of utility computing, SLAs ensure that quality standards are met between service providers and consumers. This work examines existing frameworks, identifies challenges in SLA management, and explores their implications within utility computing systems.

Utility computing, reminiscent of traditional utilities like electricity, allows users to outsource computational jobs, bypassing the need for significant infrastructure investments. This paradigm shift underscores the necessity of SLAs, particularly in maintaining user satisfaction through assured Quality of Service (QoS) parameters. The paper addresses the lifecycle of an SLA, a concept integral to its realization, which the authors delineate into six steps: service provider discovery, SLA definition, agreement establishment, SLA violation monitoring, termination, and enforcement of penalties for violations.

In terms of SLA management, several challenges and solutions are discussed. Discovering suitable service providers within vast, dynamic environments and establishing coherent SLAs that accommodate negotiation complexities are critical. The authors discuss protocols and languages for SLA definition and negotiation, including prominent frameworks like WS-Agreement and WSLA, alongside other notable approaches that cater to specific SLA lifecycle stages. The complexity of negotiating SLAs across heterogeneous systems highlights interoperability as an area needing further refinement.

The authors have meticulously analyzed various SLA use cases in both academic and industry contexts, highlighting the role of SLAs in business collaborations within Grid and Cloud computing. Risk assessment and dynamic SLA renegotiation approaches are discussed, illustrating the adaptability required in utility computing environments. Furthermore, trends in Cloud computing emphasize the automatic management of SLA parameters and resource allocation, setting it apart from traditional web service approaches.

The implications of SLA management extend beyond theoretical constructs, reflecting practical concerns such as the automatic enforcement of penalties and comprehensive monitoring of SLA adherence. Future directions in SLA research, as identified, including enhancing scalability, managing dynamic environmental changes, and extending SLA frameworks to support cross-domain applications, are essential for the evolution of utility computing infrastructures.

In conclusion, this paper delineates the multifaceted aspects of SLAs within utility computing systems, providing a valuable reference for researchers aiming to enhance SLA frameworks in service-oriented environments. The authors successfully draw attention to open challenges and potential innovations, signalling crucial pathways for advancing the robustness of utility computing systems through effective SLA management.