Cloud Workflow System Quality of Service

Abstract

Along with system functionality, the management of quality of service (QoS) in cloud workflow system is attracting increasing and even more efforts [3, 31, 45, 47, 54, 73]. This is mainly because of the following two reasons. First, the cloud computing environment is very dynamic and uncertain. Therefore, it is difficult to achieve targeted service quality if without effective QoS management strategies; Second, cloud computing adopts the market-oriented model and strict service contracts. Therefore, high service quality is necessary for improving customer satisfaction and avoiding penalty for the breach of service contracts. Therefore, QoS management plays a significant role in cloud workflow systems, and hence included as significant part of this book. In Sect. 4.1, we will first present an overview about the QoS of Web and cloud services. In Sect. 4.2, we introduce the QoS of cloud workflows. In Sect. 4.3, a generic QoS framework is presented as a high level guideline for the design of software components to deliver lifecycle QoS support in cloud workflow systems. Afterwards, as concrete examples, specific strategies for performance management (on workflow response time), cost management (on data storage), reliability management (on data replication), and security management, will be discussed and demonstrated.