Book Image

Red Hat Enterprise Linux Troubleshooting Guide

By : Benjamin Cane
Book Image

Red Hat Enterprise Linux Troubleshooting Guide

By: Benjamin Cane

Overview of this book

Red Hat Enterprise Linux is an operating system that allows you to modernize your infrastructure, boost efficiency through virtualization, and finally prepare your data center for an open, hybrid cloud IT architecture. It provides the stability to take on today's challenges and the flexibility to adapt to tomorrow's demands. In this book, you begin with simple troubleshooting best practices and get an overview of the Linux commands used for troubleshooting. The book will cover the troubleshooting methods for web applications and services such as Apache and MySQL. Then, you will learn to identify system performance bottlenecks and troubleshoot network issues; all while learning about vital troubleshooting steps such as understanding the problem statement, establishing a hypothesis, and understanding trial, error, and documentation. Next, the book will show you how to capture and analyze network traffic, use advanced system troubleshooting tools such as strace, tcpdump & dmesg, and discover common issues with system defaults. Finally, the book will take you through a detailed root cause analysis of an unexpected reboot where you will learn to recover a downed system.
Table of Contents (19 chapters)
Red Hat Enterprise Linux Troubleshooting Guide
Credits
About the Author
About the Reviewers
www.PacktPub.com
Preface
Index

The reported problem


Today's chapter, much like the other chapters, will start with someone reporting an issue. The issue being reported is that Apache is no longer running on the server, which serves the company's blog: blog.example.com.

A fellow systems administrator who is reporting the issue has explained that someone reported that the blog was down and when he logged into the server he could see Apache was no longer running. At that point, our peer was unsure what to do to continue and asked for our help.

Is Apache really down?

The first thing that we should do when a service is reported as down is to validate that it really is down. This is essentially our duplicate it for ourselves step from our troubleshooting process. With a service such as Apache, we should also validate that it is in fact down fairly quickly.

In my experience, I have often been told that a service is down when it really was not. The server may have been having an issue but it was not technically down. The difference...