A Survey on Virtualization and Hypervisor-based Technology in Cloud Computing Environment

Cloud computing is one of the today’s largest hearing fields and exciting technologies, because it is flexible and scalable, also it reduces the cost and complexity of applications. The core technology that adds to the features of cloud computing is virtualization. Virtualization is a component of cloud computing. On the basis of virtualization cloud computing allows easy deployment of workloads and their quick scaling through the rapid provisioning of virtual or physical machines. In this paper we have discussed basic virtualization technology and also several reasons as to why it has gained immense impetus in the recent years. We have also compared the scenario before and after the advent of virtualization. Virtualization works at several levels thus, in this paper we present a view on each of these levels. We also discuss hardware virtualization techniques at the hardware level which distinguish from each other on the basis of the kind of support they expect from the hardware underneath and whether the guest should be modified or not. The entire internal working of virtualization layer is dealt by the hypervisor. Hypervisor is the fundamental element of Hardware level virtualization. Furthermore, in this paper we indicate that there exist two types of hypervisors and also discuss their security concerns along with the internal organization of the hypervisors. We also present a view on certain open issues and research directions that the researchers can consider and exploit further. Keywords—cloud computing; virtualization; operating system; hypervisor