Semantic Modelling of Resource Dependability for SLA-Based Service Governance

Abstract

In this chapter we present a survey of research work related to the semantic modelling of security, semantic SLA modelling, and the current state of the art in SLA-based system governance. Based on this survey, and after observing the essential aspects needed to semantically model an SLA, we first propose a semantic model of resource dependability. This model can be used to semantically encode in SLA the service commitments (to customers) and resource capacity (from suppliers) in terms of usage, performance, and other QoS characteristics that represent non-functional properties. On the basis of this model, we propose a flexible approach to SLA-based system governance that allows for elastic provisioning of resources (by autonomic processes) that meet NFP requirements. This approach can be used to monitor and manage services such that they meet (and continue to meet) agreed levels of QoS.