云计算是一种以虚拟机化技术为核心的新型计算模式,通过网络以服务的方式,按需为用户提供动态和可伸缩的基础资源、开发环境以及应用。本文首先研究和分析了云计算及平台发展现状及意义;然后阐述了当前四大主流开源云平台的框架结构;最后总结了云计算存在的问题,从而为云计算的理论研究和评估提供一定的参考。 Cloud computing is a new computing model that takes virtualization technology as its core. It provides users with dynamic and scalable basic resources, development environments and applications on demand through services on the Internet. This paper first studies and analyzes the current situation and significance of cloud computing and platform development. Then it expatiates the framework of the four mainstream open source cloud platforms. Finally, it summarizes the existing problems of cloud computing, and thus provides some theoretical research and evaluation for cloud computing reference.