OpenStack is a free and open-source cloud computing software platform that allows customers to build their own cloud without using proprietary technologies like Amazon EC2 etc. This gives customers complete flexibility when designing their cloud as they can introspect the source code and make modifications if need be. OpenStack began in 2010 as a joint project of Rackspace Hosting and NASA. As of 2016, it is managed by the OpenStack Foundation, a non-profit corporate entity established in September 2012] to promote OpenStack software and its community. More than 500 companies have joined the project. With great power comes great responsibility, and implementing OpenStack is left to the customer. This is the key differentiator between OpenStack and other public cloud providers.
What do we mean by this?
A free and open-source cloud computing software platform