Platform & DevOps·Infrastructure described in a file
an agent installs the packages, writes the files and restarts the service on machines that already exist, over and over.
Configuration management
Also calledconfig management, server configuration, convergent configuration
Bringing the inside of an already-running machine to a desired state — packages, files, users, services — repeatedly. It was the dominant discipline when servers were long-lived, and immutable infrastructure has taken most of its work away by rebuilding the image instead. It remains genuinely necessary wherever machines are long-lived and cannot simply be replaced, which is most estates that predate containers.