SaltStack (see https://saltstack.com/), first released in 2011, is an automation suite which offers Configuration Management plus standard and/or event-driven orchestration. It is commonly used in a master-minion setup, where a master node provides centralized control across a compute estate. It is known for its speed and scalability thanks to the fast and lightweight message bus (ZeroMQ) used for communication between the salt-master and minions. It can also be used in an agentless fashion, where the minions are controlled over SSH, similarly to how Ansible operates.
SaltStack is written in Python and is easily extensible. You can write your own modules for it, attach long-running processes to its event bus, and inject raw Python code in unusual places.
The master-minion model is quite powerful, offers a lot of flexibility, and is the recommended approach if you are looking after anything more than a few dev nodes and want to take advantage of all the features SaltStack...