DevOps Troubleshooting: Linux Server Best Practices

by Kyle Rankin

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DevOps can help developers, QAs, and admins work together to solve Linux server problems far more rapidly, significantly improving IT performance, availability, and efficiency. To gain these benefits, however, team members need common troubleshooting skills and practices.

In DevOps Troubleshooting: Linux Server Best Practices, award-winning Linux expert Kyle Rankin brings together all the standardised, repeatable techniques your team needs to stop finger-pointing, collaborate effectively, and quickly solve virtually any Linux server problem. Rankin walks you through using DevOps techniques to troubleshoot everything from boot failures and corrupt disks to lost email and downed websites. You’ll master indispensable skills for diagnosing high-load systems and network problems in production environments.

Rankin shows how to

• Master DevOps’ approach to troubleshooting and proven Linux server problem-solving principles
• Diagnose slow servers and applications by identifying CPU, RAM, and Disk I/O bottlenecks
• Understand healthy boots, so you can identify failure points and fix them
• Solve full or corrupt disk issues that prevent disk writes
• Track down the sources of network problems
• Troubleshoot DNS, email, and other network services
• Isolate and diagnose Apache and Nginx Web server failures and slowdowns
• Solve problems with MySQL and Postgres database servers and queries
• Identify hardware failures–even notoriously elusive intermittent failures

Product Details

ISBN-13:	9780133035506
Publisher:	Pearson Education
Publication date:	11/09/2012
Sold by:	Barnes & Noble
Format:	eBook
Pages:	240
File size:	11 MB
Note:	This product may take a few minutes to download.
Age Range:	18 Years

About the Author

Kyle Rankin, a senior systems administrator and DevOps engineer, is president of the North Bay Linux Users’ Group and is an award-winning columnist for Linux Journal. Rankin speaks frequently on open source software at SCALE, OSCON, Linux World Expo, Penguicon, and many Linux user groups. His other books include The Official Ubuntu Server Book; Knoppix Hacks, Second Edition; Knoppix Pocket Reference; and Linux Multimedia Hacks. He is also coauthor of Ubuntu Hacks.

 

Table of Contents

Preface         xiii

Acknowledgments         xix

About the Author         xxi

 

Chapter 1: Troubleshooting Best Practices         1

Divide the Problem Space 3

Practice Good Communication When Collaborating 4

Favor Quick, Simple Tests over Slow, Complex Tests 8

Favor Past Solutions 9

Document Your Problems and Solutions 10

Know What Changed 12

Understand How Systems Work 13

Use the Internet, but Carefully 14

Resist Rebooting 15

 

Chapter 2: Why Is the Server So Slow? Running Out of CPU, RAM, and Disk I/O         17

System Load 18

Diagnose Load Problems with top 20

Troubleshoot High Load after the Fact 29

 

Chapter 3: Why Won’t the System Boot? Solving Boot Problems         35

The Linux Boot Process 36

BIOS Boot Order 45

Fix GRUB 47

Disable Splash Screens 51

Can’t Mount the Root File System 51

Can’t Mount Secondary File Systems 55

 

Chapter 4: Why Can’t I Write to the Disk? Solving Full or Corrupt Disk Issues         57

When the Disk Is Full 58

Out of Inodes 61

The File System Is Read-Only 62

Repair Corrupted File Systems 63

Repair Software RAID 64

 

Chapter 5: Is the Server Down? Tracking Down the Source of Network Problems         67

Server A Can’t Talk to Server B 68

Troubleshoot Slow Networks 78

Packet Captures 83

 

Chapter 6: Why Won’t the Hostnames Resolve? Solving DNS Server Issues         93

DNS Client Troubleshooting 95

DNS Server Troubleshooting 98

 

Chapter 7: Why Didn’t My Email Go Through? Tracing Email Problems         119

Trace an Email Request 120

Understand Email Headers 123

Problems Sending Email 125

Problems Receiving Email 135

 

Chapter 8: Is the Website Down? Tracking Down Web Server Problems         141

Is the Server Running? 143

Test a Web Server from the Command Line 146

HTTP Status Codes 149

Parse Web Server Logs 154

Get Web Server Statistics 158

Solve Common Web Server Problems 163

 

Chapter 9: Why Is the Database Slow? Tracking Down Database Problems          171

Search Database Logs 172

Is the Database Running? 174

Get Database Metrics 177

Identify Slow Queries 182

 

Chapter 10: It’s the Hardware’s Fault! Diagnosing Common Hardware Problems         185

The Hard Drive Is Dying 186

Test RAM for Errors 190

Network Card Failures 191

The Server Is Too Hot 192

Power Supply Failures 194

 

Index         197