Ansible is an open-source IT automation tool founded in 2012 and acquired by Red Hat in 2015, built on an agentless architecture, YAML playbooks and idempotent execution for configuration management and application deployment.
SaltStack (Salt Project) was created in 2011 by Thomas Hatch as an open-source configuration management and remote execution platform, acquired by VMware in 2020.
CFEngine was created in 1993 by Mark Burgess in Oslo, Norway, and is the oldest IT automation configuration management tool, based on the unique Promise Theory design.