Automating Linux
and Unix System
Administration
Second Edition
Nate Campi and Kirk Bauer
Automating Linux and Unix System Administration, Second Edition
Copyright © 2009 by Nate Campi, Kirk Bauer
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I dedicate this book to my dear grandmother Mary Lou.
Her influence makes everyone around her a better person,
and her presence lights up a room.
She is beautiful inside and out,
and she meets adversity with faith,
quiet dignity, and grace.
—Nate Campi
v
About the Authors .................................................................xv
About the Technical Reviewer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xvii
Acknowledgments ................................................................xix
Introduction .....................................................................xxi
CHAPTER 1 Introducing the Basics of Automation ............................1
CHAPTER 2 Applying Practical Automation ..................................19
CHAPTER 3 Using SSH to Automate System Administration Securely .........27
CHAPTER 4 Configuring Systems with cfengine .............................49
CHAPTER 5 Bootstrapping a New Infrastructure .............................79
CHAPTER 6 Setting Up Automated Installation ..............................107
CHAPTER 7 Automating a New System Infrastructure .......................161
CHAPTER 8 Deploying Your First Application ...............................213
CHAPTER 9 Generating Reports and Analyzing Logs ........................253
CHAPTER 10 Monitoring ....................................................273
CHAPTER 11 Infrastructure Enhancement ...................................323
CHAPTER 12 Improving System Security ....................................353
APPENDIX A Introducing the Basic Tools ....................................375
APPENDIX B Writing cfengine Modules. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 395
INDEX .......................................................................401
Contents at a Glance
vii
Contents
About the Authors .................................................................xv
About the Technical Reviewer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xvii
Acknowledgments ................................................................xix
Introduction .....................................................................xxi
CHAPTER 1 Introducing the Basics of Automation ......................1
Do You Need Automation? .........................................2
Large Companies with Many Diverse Systems ...................4
Medium-Sized Companies Planning for Growth ..................4
Internet Service Providers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Application Service Providers ..................................5
Web Server Farms ...........................................5
Beowulf Clusters ............................................6
Network Appliances ..........................................7
What Will You Gain? ..............................................7
Saving Time ................................................7
Reducing Errors .............................................7
Documenting System Configuration Policies ....................8
Realizing Other Benefits ......................................8
What Do System Administrators Do? ...............................10
Methodology: Get It Right from the Start! ...........................11
Homogenizing Your Systems .................................13
Deciding on Push vs. Pull ....................................13
Dealing with Users and Administrators .............................14
Who Owns the Systems? .........................................17
Defining Policy ..................................................18
