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
About the Author
About the Reviewers

Trial and error

Now that we have identified our issue with data collection and established a possible cause with our hypothesis, we can start our next troubleshooting step: using trial and error to correct the issue.

Removing the invalid route

To correct our issue, we need to remove the invalid route for To do this, we will yet again use the ip command, this time with the route del options.

[db]# ip route del
[db]# ip route show
default via dev enp0s3  proto static  metric 1024 dev enp0s3  proto kernel  scope link  src dev enp0s8  scope link  metric 1003 dev enp0s8  proto kernel  scope link  src

In the preceding example, we used the ip command with the route del options to remove a route that targets a single IP. We can use the same command and options to remove routes that are defined for subnets. The following example will remove the route for the network:

[db]# ip route...