Improving Fault Tolerance in Virtual Machine Based Cloud Infrastructure

摘要

Cloud Computing is a style of Computing where service is provided across the internet using different models. Fault tolerance is a major concern to guarantee availability and reliability of critical services as well as application execution. In this project work, we propose a model to analyze how system tolerates the faults and make decision on the basics of reliability of the processing nodes, i.e. Virtual machines. If a virtual machine manages to produce a correct result within the time limit, its reliability increases, and if it fails to produce the result within time or correct result, its reliability decreases. If the node continues to fail, it is removed, and a new node is added. There is also a minimum reliability level. If any processing node does not achieve that level, the system will perform backward recovery or safety measures. The proposed technique is based on the execution of design diverse variants on multiple virtual machines, and assigning reliability to the results produced by variants. The virtual machine instances can be of same type or of different types. The system provides both the forward and backward recovery mechanism, but main focus is on forward recovery.