Automating Linux Unix



Apress || ISBN-13: 978-1-4302-1059-7 || Author: Nate Campi and Kirk Bauer || English || PDF || 431 Pages || Size: 1.76 MB

Introduction
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.

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 administrator 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 systems to a known good state, and implement changes reliably across all systems (or only an appropriate subset). We do not claim that the approaches, procedures, and tools used in this book are the only way to set up and maintain a UNIX-based environment. Instead, we walk you through the creation of an example environment, and during the process, help you gain a solid understanding of the basic principles of system automation. This way, you can decide for yourself how you want to set up your own UNIX-based environment. This book isn’t like most UNIX/Linux administration books, because it illustrates techniques and principles by building a real UNIX/Linux environment from scratch. We demonstrate that you can configure each host at your site, from installation through production service to system retirement, without logging in and making manual changes to the host. Instead, we’ll configure the hosts via imaging systems designed for unattended installation, followed by management with an automation framework. We wrote this book, because we felt that it is important to demonstrate that an entire site can be managed using automation. Our goal is to be able to quickly, easily, and reliably restore hosts to service after complete system failure. The host might have failed due to hardware issues; an entire geographic region might be unreachable due to natural disaster, or you might simply have purchased updated hardware on which to run that particular host and need to upgrade. The point o our approach is to configure a host only once and, from that point on, allow an automation system to do that work for you. Whether you choose to use our exact setup or something completely different, you’ll have gained knowledge and experience by going though the process with us in our example environment. Our promise to you is that if you need to configure a new UNIX-based infrastructure from scratch (and you’re able or allowed to use the operating systems and software we demonstrate), you can use this book to create a fully functional and scalable new infrastructure. Every service and piece of architecture that our new environment needs is set up using automation. This book moves fast and will be best utilized if you follow along with the examples and implement the described steps on systems of your own. In addition, download the code and configuration files from the Source Code page of the Apress web site ( ).

Who This Book Is For
This book is written for the experienced system administrator. We have made every attempt to refer you to appropriate external sources when we weren’t able to delve into great detail on a service or protocol that we were automating. In addition, little explanation s given to the usage of basic UNIX/Linux commands and shell scripts. You don’t, however, have to be an advanced system administrator. We feel that a system administrator with only one or two years of full-time on-the-job experience is more than ready to utilize the concepts and tools in this book.

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