The document introduces the China OpenStack User Group (COSUG) and provides an overview of OpenStack. It describes OpenStack as an open source cloud operating system that delivers scalable cloud technologies. It discusses why OpenStack is important for standardizing cloud infrastructure and making it portable across providers. The document outlines OpenStack's open philosophy and design principles, and provides summaries of key OpenStack projects like Nova, Glance, and Swift. It also reviews OpenStack's release process and goals of COSUG in promoting OpenStack adoption in China.