Automating UNIX and Linux Administration by Kirk Bauer Apress © 2003 ISBN:1590592123 This book focuses on automating the tedious daily tasks of system administration It provides real-world examples and explores the tools useful for managing 2 or 5,000 systems Table of Contents Automating UNIX and Linux Administration Preface Chapter 1 - Introducing the Basics of Automation Using SSH to Securely Automate System Chapter 2 Administration Chapter 3 - Creating Login Scripts and Shell Scripts Pre-Installation—Network Preparation Chapter 4 and Management Chapter 5 - Automating and Customizing Installation Chapter 6 - Automatic System Configuration Chapter 7 - Sharing Data Between Systems Chapter 8 - Packages and Patches Chapter 9 - System Maintenance and Changes Chapter 10 - System Monitoring Chapter 11 - Improving System Security Chapter 12 - Backing Up and Restoring Data Chapter 13 - User Interfaces Appendix A - Introduction to Basic Tools Appendix B - Customizing and Automating Red Hat Linux Installation Building Red Hat Package Manager (RPM) Appendix C Packages Index List of Figures List of Tables List of Sidebars Back Cover Wouldn’t you like to automate the tedious daily tasks of system administration? Automating UNIX and Linux Administration will show you how, by exploring existing tools and offering real-world examples Parts of the book are Linux-specific, but most of it applies to a UNIX system, including multiple variants of UNIX Author Kirk Bauer briefly overviews tools and technologies—and assumes preliminary knowledge about editing a configuration file or mounting a file system The techniques, methods, and tools in this book will help you manage a single system—but will prove especially powerful across multiple systems No matter if the systems are desktops, servers, or Beowulf clusters—all of them will benefit from this automation And managing five to five thousand systems will become a simpler task! About the Author Kirk Bauer has been involved in computer programming since 1985 He has been using and administering UNIX systems since 1994 Although his personal favorite UNIX variant is Linux, he has administered and developed on everything from FreeBSD to Solaris, AIX, and IRIX He is the author of various open-source system administration programs such as AutoRPM and Logwatch Bauer has been involved with software development and system/network administration since his first year at Georgia Tech He has done work for the Georgia Tech Residential Network, the Georgia Tech Research Institute, and the Fermi National Accelerator Laboratory Bauer was one of the founders and the CTO of TogetherWeb in 2000, which was purchased in 2003 by Proficient Systems He is currently a software architect with Proficient Systems, and continues to support and develop the collaborative browsing software and Linux-based network appliance created by TogetherWeb, including C++ server software that provides high scalability, high efficiency, and high reliability Kirk graduated from Georgia Tech in 2001 with a bachelor’s degree in computer engineering Shortly thereafter, he began work on his first book, Automating UNIX and Linux Administration, which was published by Apress in September 2003 Automating UNIX and Linux Administration Kirk Bauer Apress™ Copyright © 2003 Kirk Bauer All rights reserved No part of this work may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or by any information storage or retrieval system, without the prior written permission of the copyright owner and the publisher (pbk): 1-59059-212-3 10987654321 Trademarked names may appear in this book Rather than use a trademark symbol with every occurrence of a trademarked name, we use the names only in an editorial fashion and to the benefit of the trademark owner, with no intention of infringement of the trademark Technical Reviewers: Nate Campi, Erik Melander, Alf Wachsmann Editorial Board: Dan Appleman, Craig Berry, Gary Cornell, Tony Davis, Steven Rycroft, Julian Skinner, Martin Streicher, Jim Sumser, Karen Watterson, Gavin Wray, John Zukowski Assistant Publisher: Grace Wong Copy Editor: Rebecca Rider Production Manager: Kari Brooks Proofreader: Laura Cheu Compositor: Susan Glinert Stevens Indexer: Kevin Broccoli Cover Designer: Kurt Krames Manufacturing Manager: Tom Debolski Distributed to the book trade in the United States by Springer-Verlag New York, Inc., 175 Fifth Avenue, New York, NY, 10010 and outside the United States by Springer-Verlag GmbH & Co KG, Tiergartenstr 17, 69112 Heidelberg, Germany In the United States: phone 1-800-SPRINGER, email orders@springerny.com, or visit http://www.springer-ny.com Outside the United States: fax +49 6221 345229, email orders@springer.de, or visit http://www.springer.de For information on translations, please contact Apress directly at 2560 Ninth Street, Suite 219, Berkeley, CA 94710 Phone 510-549-5930, fax 510-549-5939, email info@apress.com, or visit http://www.apress.com The information in this book is distributed on an "as is" basis, without warranty Although every precaution has been taken in the preparation of this work, neither the author(s) nor Apress shall have any liability to any person or entity with respect to any loss or damage caused or alleged to be caused directly or indirectly by the information contained in this work The source code for this book is available to readers at http://www.apress.com in the Downloads section To my parents, especially my father, who started and supported my interest in computers, and my loving wife Amber, who has supported me throughout this process About the Author Kirk Bauer has been using computers and programming since 1985 He has been using and administering UNIX systems since 1994 Although his personal favorite UNIX variant is Linux, he has administered everything from FreeBSD to Solaris, AIX, and IRIX Kirk has been involved with software development and system/network administration since his first year at Georgia Tech He has done work for the Georgia Tech Residential Network, the Georgia Tech Research Institute, and the Fermi National Accelerator Laboratory Kirk was one of the founders and the CTO of TogetherWeb in 2000, which was purchased in 2003 by Proficient Systems Kirk is currently a software architect with Proficient Systems and continues to support and develop the collaborative browsing software and Linux-based network appliance created by TogetherWeb Kirk's latest development is a fully automated installation, configuration, management, and monitoring system that is used to deploy Proficient's software on RLX ServerBlades Saving time through automation has always been his passion, as evidenced by his collection of open-source software—the most popular being AutoRPM and Logwatch Shortly after graduating from Georgia Tech in 2002 with a bachelor's of science in Computer Engineering, Kirk married Amber, the love of his life They currently live in Peoria, AZ with their two dogs and four cats When not using a computer, Kirk can be found involved in one of his many hobbies Kirk enjoys reading, playing strategy games, taking pictures, and watching movies He likes to snow ski, water ski, and scuba dive when he gets the opportunity Skydiving is his favorite sport— Kirk has made over 1,400 jumps to date About the Technical Reviewers Nate Campi is a UNIX and network administrator in Silicon Valley He is currently employed at a (Linux-based) network appliance vendor, running all aspects of their internal IT, helping guide development of products, and designing DNS architectures for customers Past jobs include postmaster, hostmaster, and webmaster duties at Terra Lycos, UNIX and network administrator at several Silicon Valley web hosting companies, and a tour as a hospital corpsman in the US Navy While in the Navy, Nate developed a love of teaching as a instructor for basic and advanced life support, and also pediatric advanced life support for the American Heart Association He is married, has a son and a daughter, lives in the San Francisco East Bay, and dreams of one day owning a home in the area Erik Melander, Managing Architect of Central Systems at Wyndham International, has a decade of experience with UNIX systems, including time working with the University of Minnesota and IBM Global Services Currently, he is evolving Wyndham's IT infrastructure to realize a shared vision of autonomic computing Alf Wachsmann holds a doctorate of natural science in Computer Science from the University of Paderborn in Germany He wrote his thesis about parallel and distributed computing He then worked at DESY, Germany's national high-energy physics lab, where he learned system software programming and system administration in a very heterogeneous UNIX environment His specialty became automation Wachsmann then moved from Germany to the San Francisco Bay area, where he now works at the Stanford Linear Accelerator Center, a site with fewer UNIX versions but with a lot more computers His main focus is again automating system administration and system infrastructure tasks Other professional interests include the OpenAFS filesystem and Kerberos 5 authentication Acknowledgments I have used computers since I was very young and have always loved them, thanks in large part to the support of my parents throughout my childhood They have always helped me learn and have supported me in whatever I wanted to do I have to particularly thank my father who, much to my Mom's chagrin, came home one day with my very first computer— a Commodore Vic 20 My life was never the same after that I also thank my lovely wife, Amber, who has shared me with this book for many, many months She has been supportive and understanding, even though I started writing the book just after our honeymoon was over In addition, my friend and colleague Moshe Jacobson has been very helpful in this process He quickly answered my many questions and even did some of the technical review He helped make writing this book the learning experience that it was Finally, I must thank everybody at Apress for helping me through my first book—especially my editor, Jim Sumser, who has stuck by me through this long and arduous process Preface Admit it You are reading this book because you are lazy Lazy system administrators are wonderful people—who else is willing to spend so much time now in order to do nothing later? We all dream of waking up in the morning, grabbing the laptop from the bedside table, checking our email, and then heading off to the lake for the day Using the techniques in this book, you can get closer to the ideal world of fully automated system administration Although unexpected things always go wrong, we can at least delegate all of the mundane and repetitive tasks to the computer (whose purpose, of course, was to make our lives easier) I will leave it up to you to convince your boss that you only need to come in to work one day per week Index X x operator, 63 -x option, 470 X Window System group, 499 X11 forwarding, 25, 26 Ximian desktop, 265 -xOf options, 234 Index Y yellow background, 39 Yellow Pages (YP) See NIS (Network Information Service) yellow text, 39 -yes option, 259 Yesterday value, 338 yp_group_file, 292 yp_passwd_file, 292 ypbind, 169 ypcat command, 165, 169 ypchfn command, 169 ypchsh command, 169 yppasswd command, 169, 310 ypserv, 168 Index Z Z flag, 316 zgrep command, 518 zless command, 518 zmore command, 518 List of Figures Chapter 13: User Interfaces Figure 13-1: System status overview Figure 13-2: System configuration page Figure 13-3: Command execution options Figure 13-4: Command execution results Figure 13-5: Remote command execution options List of Tables Chapter 3: Creating Login Scripts and Shell Scripts Table 3-1: ANSI Color Codes Table 3-2: Example Host Groups Chapter 10: System Monitoring Table 10-1: NetSaint Plugin Return Codes List of Sidebars Preface Sidebars Chapter 2: Using SSH to Securely Automate System Administration Is Your Network Secure? Should I Use an Empty Passphrase? What Size Key Should I Use? Be Careful with ssh-agent Forwarding! Always Watch for Race Conditions! Chapter 3: Creating Login Scripts and Shell Scripts Sharing the root Account Chapter 7: Sharing Data Between Systems Using the home Pattern Without NFS Mounting File Permissions with CVS Appendix B: Customizing and Automating Red Hat Linux Installation RPMs and Security Kickstart and Timeouts ... Automating UNIX and Linux Administration, which was published by Apress in September 2003 Automating UNIX and Linux Administration Kirk Bauer Apress Copyright © 2003 Kirk Bauer All rights reserved No part of this work may be reproduced or transmitted... Wouldn’t you like to automate the tedious daily tasks of system administration? Automating UNIX and Linux Administration will show you how, by exploring existing tools and offering real-world examples Parts of the book are Linux- specific, but most of it applies to a... provides high scalability, high efficiency, and high reliability Kirk graduated from Georgia Tech in 2001 with a bachelor’s degree in computer engineering Shortly thereafter, he began work on his first book, Automating UNIX and Linux Administration, which was