When you install OpenStack, you will get a very simple Linux VM image (Cirros) to test your installation. This works fine for testing purposes, but you will probably want to add some VM images for CentOS or Ubuntu. Although there
OpenStack is open source software for building private and public clouds. There are several ways to install OpenStack. This guide will walk you through the installation of DevStack, which is a documented shell script to build complete OpenStack development environments.