The Simian Army is a suite of tools made available by Netflix on GitHub as an open source project. The army consists of monkeys (different tools) ranging from Chaos Monkey and Janitor Monkey to Conformity Monkey. Each monkey specializes in a certain objective, such as bringing down a subsystem, removing underutilized resources, or resources that do not conform to predefined rules (such as tagging). Using the Simian Army tool is a great way to test your systems in a gameday-like situation, where your engineers and admins are on the alert and are ready to remedy the system if it fails to deal with the outcome of the Simian Army's attack. Netflix has these tools running consistently during the work day, allowing engineers to constantly test the effectiveness of their design. As subsystems are taken down by the army, the self-healing aspects of the applications are subjected to punishing tests.

The Simian Army is on GitHub at https://github.com/Netflix/SimianArmy.