Fault tolerance and resilience in cloud computing environments," Computer and information security handbook, 2nd edn

The increasing demand for flexibility and scalability in dynamically obtaining and releasing computing resources in a cost-effective and device-independent manner, and easiness in hosting applications without the burden of installation and maintenance has resulted in a wide adoption of the Cloud computing paradigm. While the benefits are immense, this computing paradigm is still vulnerable to a large number of system failures and, as a consequence, there is an increasing concern among users regarding the reliability and availability of Cloud computing services. Fault tolerance and resilience serve as an effective means to address user’s reliability and availability concerns. In this chapter, we focus on characterizing the recurrent failures in a typical Cloud computing environment, analyzing the effects of failures on user’s applications, and surveying fault tolerance solutions corresponding to each class of failures. We also discuss the perspective of offering fault tolerance as a service to user’s applications as one of the effective means to address user’s reliability and availability concerns