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

Why is the job failing?


Since the issue being reported is that a scheduled job is not working, we should first focus on the job itself. In this scenario, we have the application support team available to answer any questions. So, let's get a few more details about this job.

Background questions

The following is a quick list of questions that should help provide you with additional information:

  • How is the job run?

  • Can we run the job manually if we need to?

  • What does this job execute?

These three questions may seem pretty basic, but they are important. Let's first look at the answers the application team provides:

  • How is the job run?

    The job is executed as a cron job.

  • Can we run the job manually if we need to?

    Yes, it should be okay to execute the job manually as often as needed.

  • What does this job execute?

    The job executes the /opt/myapp/bin/processor command as the vagrant user.

The preceding three questions are important because they will save us quite a bit of troubleshooting time. The first question...