This document discusses fault tolerance methods in cloud computing. It begins with an introduction to cloud computing and its characteristics like on-demand resources, multi-tenancy, and decreased costs. It then discusses fault tolerance as being essential for guaranteed availability and reliability of critical applications in the cloud. The document reviews different fault tolerance techniques including reactive fault tolerance policies using replication, checkpointing, and job migration as well as proactive policies using software rejuvenation and preemptive migration. Related work on fault tolerance models and frameworks is also summarized.