your configuration information is in one place (and that place isn't someone's head) • You can spin up perfectly configured servers instantly! • You can change things in one place and have them propagate through your entire system • You can create dev and test environments that are exact replicas of production.
does and what should be installed on it. I.e. a webserver role vs. a database role • run_list of installations • Can talk about other machines in your infrastructure by their role; open up firewalls to front-end servers • You can query roles