Research On Virtualization Techniques For Cloud Desktop Services

With the rapid development of computer and network,more and more enterprises employ computer technology to achieve automation management.However,as the expanding of enter-prises and the explosive growth of computers,traditional office systems that based on Personal Computers(PC)cause a waste of computer resources and increase costs of management and maintenance greatly.At the same time,as the rapid development of cloud computing and vir-tualization technologies,desktop cloud service emerges.Compared to traditional PC desktops,desktop cloud service which is based on cloud computing and desktop virtualization provides a lot of advantages for IT enterprises such as reducing maintenance and operating costs and improving resource utilization efficiency.However,existing desktop cloud systems still suffer several bottlenecks such as lack of standards,security threaten,availability and performance and experience problems.Performance and experience issues are very important since they are closely related to users' acceptance for desktop cloud services.Specially,the main three perfor-mance and experience problems in existing desktop cloud services are as follows:(1)User Experience for High-Definition Videos.Most of existing desktop cloud systems utilize image compression or copying framebuffer to replay high-definition(HD)videos in virtual desktops,which may cause poor video quality,dropped frames,high CPU cost and compatibility issues due to the large amount of data of HD videos.Those issues will greatly degrade user experience for replaying HD videos in desktop cloud systems.(2)User Experience for Mobile Devices.The rapid adoption of smart mobile devices and the popularity of Bring Your Own Device(BYOD)policy bring the urgent requirements for mobile cloud desktops.However,existing desktop cloud systems are designed only for Windows operating system,it may cause screen and application compatibility issues on Android based mobile devices,which greatly degrade user experience for mobile users.(3)Performance of Virtual Applications.Existing desktop cloud systems are commonly deployed in virtual machines which are based on hardware simulation,applications running in virtual execution environments may suffer from performance degradation due to the limitation of the virtualization technologies.Especially for mobile devices with a variety of I/O interfaces,the weakness of I/O virtualization may lead to the crash of mobile applications.To address the above problems,the following work has been done in this thesis:(1)To improve the user experience for replaying high-definition videos in desktop virtual-ization systems,we make a deep analysis on traditional remote display system,GPU acceleration and GPU virtualization,and we propose a GPU virtualizaiton based solution for replaying high-definition videos in cloud desktops.In this solution,the virtual display driver on the server side is modified so that the media player applications are able to handle high-definition videos with virtual GPU,then video content is intercepted at the driver layer and delivered to client in its originally encoded state,the decoding commands are also redirected to the client so that the video content can be decoded and rendered on the client.The experimental results show that,this solution provides almost 100%quality and 30 frame rate for replaying videos with 1080x720 or above resolution in cloud desktops with a little CPU cost.In addition,this solution is adapted for the most of video codecs and media player applications since it is mainly implemented at the driver layer.(2)To improve the service quality and user experience of cloud desktops for mobile devices.We propose a desktop virtualization system for Android mobile platform.The architecture of the proposed system is designed in a guest-OS model,and deployed by analyzing and reconstructing the data-flow management of Android system.In addition,a multi-channel strategy is applied in this system for data transfer under different scenario.This system focuses on virtualizing the display of Android desktops,redirecting users' input events,audio support and remote camera.The experimental results show that the response time and network bandwidth consumption of the Android desktop virtualization system are acceptable for common users,and the proposed system can provide remote mobile users with good support for audio and camera.(3)To further improve the application performance and user experience in mobile desktop virtualization environment and reduce the resource consumption on the server side,we make a deep analysis and comparison on existing server virtualization technologies and propose a con-tainer based solution to deploy mobile virtual desktop service.In the solution,we utilize Linux Container(LXC)to build a container virtualization platform for Android system,and redesign the Android desktop virtualization system proposed in work(2)by an non-invasive method,then we deploy the Android virtual desktop into the container environments.The experimental results show that Android virtual desktops in containers perform better than that in traditional virtual machines in terms of application performance and system overhead,which is good for the large-scale deployment of mobile virtual desktop.In addition,the non-invasive implementation of the system greatly improves the generality and maintainability.