OpenStack is a leading open-source project to build public/private clouds. In this talk, a brief introduction of Openstack will be presented, following by a detail technical description of internal structure of main openstack software, including openstack compute, storage, and glance. This talk will also introduce a Dell's crowbar solution to automatically deploy and configure openstack software to build a large scale cloud infrastructure. Finally, Information about some of on-going development effort in the community will be shared with audience.