OpenStack is distributed as an Infrastructure as a service (IaaS) solution which was released under the terms of Apache license.
OpenStack can be run as a PaaS provider on IaaS providers like Amazon EC2, Rackspace and GoGrid.
It is designed to manage and automate pools of computer resources and can work with widely available virtualization technologies, as well as bare metal and high-performance computing (HPC) configurations.
KVM and Xen are available choices for hypervisor technology, together with Hyper-V and Linux container technology such as LXC.
We can run openstack on the operating systems like Linux, Windows and Bare Metal. OpenStack will run as a virtual instance on Linux, Windows, VMware, Xen and KVM.
OCCI and S3 are the two main features enabled in OpenStack software where OCCI supports Open Cloud Computing interface and S3 supports Amazon S3 volumes.
OpenStack serves the needs of the vendors, so they have a technology base and a marketing brand to build their own cloud stacks.