Puppet describes desired system state in a domain-specific language — installed packages, file permissions, running services — and enforces it on agents. Enterprises used it to manage thousands of nodes before Ansible and cloud-native tooling. Example: declare `nginxA high-performance web server and reverse proxy — event-driven design for massive concurrency.` installed and a config file templated from a central catalog.

Puppet pioneered idempotent, model-driven infrastructure automationUsing machines or software to perform tasks with minimal human intervention. for production fleets.

It proved declarative config management could scale beyond shell scripts and CFEngine.