Automatic software deployment using user-level virtualization for cloud-computing

Cloud Computing offers a flexible and relatively cheap solution to deploy IT infrastructure in an elastic way. An emerging cloud service allows customers to order virtual machines to be delivered virtually in the cloud; and in most cases, besides the virtual hardware and system software, it is necessary to deploy application software in a similar way to provide a fully-functional work environment. Most existing systems use virtual appliances to provide this function, which couples application software with virtual machine (VM) image(s) closely. This paper proposes a new method based on the user-level virtualization technology to decouple application software from VM to improve the deployment flexibility. User-level virtualization isolates applications from the OS (and then the lower-level VM); so that a user can choose which software will be used after setting the virtual machines' configuration. Moreover, the chosen software is not pre-installed (or pre-stored) in the VM image; instead, it can be streamed from the application depository on demand when the user launches it in a running VM to save the storage overhead. During the whole process, no software installation is needed. Further, the enormous existing desktop software can be converted into such on-demand versions without any modification of source code. We present the whole framework, including the application preparation, the runtime system design, the detailed deployment and usage workflow, and some optimizations. At last, test results show that this solution can be efficient in performance and storage. (C) 2011 Elsevier B.V. All rights reserved.