OpenStack is a cloud management platform which allows users to create virtual machines according to physical criteria (number of CPUs, amount of memory, disk storage etc.) and a base image that can provide the operating system and the most suitable software. It also has features volume demand (such as Amazon EBS) via Cinder (block storage), network on demand via quantum of cloud storage mode via Swift (a scalable redundant storage system).
As we all know OpenStack is based solely on open source tools: Linux, Libvirt, QEMU / KVM and is written in Python. It meets many standards ovf (open virtual machine format), qcow2 (to create a snapshot of existing files), EC2 or S3, and specific APIs (Nova).