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