Chef
Site: https://www.chef.io/
Chef is a configuration management tool written in Ruby and Erlang. It uses a pure-Ruby, domain-specific language (DSL) for writing system configuration "recipes". Chef is used to streamline the task of configuring and maintaining a company's servers, and can integrate with cloud-based platforms such as Rackspace, Internap, Amazon EC2, Google Cloud Platform, OpenStack, SoftLayer, and Microsoft Azure to automatically provision and configure new machines.