Automating Linux and Unix System Administration

The system administrator is one of the users of a system, and something more. The administrator wears many hats, as knowledgeable user of UNIX commands, as an operator of system hardware, and as a problem solver. The administrator is also called upon to be an arbitrator in human affairs. A multiuser computer is like a vast imaginary space where many people work and utilize the resources found there. The administrator must be the village elder in this space and settle the disputes that may arise with, hopefully, the wisdom of Solomon. --Rebecca Thomas and Rik Farrow (UNIX Administration Guide for System V, Pearson PTR, 1989) We find it interesting how little UNIX system administration has changed in the last twenty years. If you substitute "computer network" for "multiuser computer," this description still fits perfectly. The main difference in UNIX system administration between 1989 and 2008 (besides ubiquitous networking) is the sheer number of systems that the average system adm- istrator deals with. Automation is the primary tool to deal with the chaos that can result from so many systems. With it, you can deploy systems identically every time, restore s- tems to a known good state, and implement changes reliably across all systems (or only an appropriate subset).