CFEngine is an infrastructure automation tool born in 1993 that uses agent-based policies to define how systems should be configured and maintained. The tool is highly scalable, with a single server able to manage up to 5,000 agents, and is highly portable as it is written in a programming language that allows it to run on various operating systems. Agents in CFEngine are not fully dependent on the server and can continue working even if communication is lost, making the automation resilient.