Ansible - Radically simple configuration-management, application deployment, task-execution, and multi-node orchestration engine
Terraform - Tool for building, changing, and versioning infrastructure safely and efficiently.
Chef - Automation for all of your technology. Overcome the complexity and rapidly ship your infrastructure and apps anywhere with automation.
RunDeck - RunDeck is an open source automation service with a web console, command line tools and a WebAPI.
SaltStack - SaltStack event-driven automation delivers security, cloud and configuration management for a software-defined world and enterprise complexity and scale.
Salt - Fast, scalable and flexible software for data center automation