Preface

Overview

Linux is thriving. Red Hat is at the forefront of the Linux revolution. And Red Hat Certified Engineers and Technicians are making it happen.

Even in the current economic recovery, business, education, and governments are cost conscious. They want control of their operating systems. Linux-even Red Hat Enterprise Linux-saves money. The open source nature of Linux allows users to control and customize their operating systems. While there is a price associated with Red Hat Enterprise Linux (RHEL), the cost includes updates and support. Now with Xen, it's possible to set up a cluster of virtual, independent installations of RHEL (and other operating systems) on a single physical computer. As I describe shortly, there are freely available "rebuilds" of RHEL that you can get without support from Red Hat, with features identical for most administrators.

On the Job 

A "rebuild" is software that is built by a third party from the same source code as the original "build." On the other hand, a "clone" is built from different source code.

As this book is going to print, the New York Stock Exchange has just announced that it's moving to Linux. Major corporations, from Home Depot to Toyota, and governments such as Brazil, the Republic of Korea, and Switzerland have made the switch to Linux. When faced with a Microsoft audit for licenses, the Portland, Oregon, school system switched to Linux. Major movie studios such as Disney and Dreamworks use Linux to create the latest motion pictures. IBM has invested billions in Linux -and constantly features Linux in its advertising. HP has reported 2.5 billion dollars in Linux-related revenue in 2003, and it's still growing today (2007). Even though Linux is freely downloadable, Wall Street Technology just reported that Linux server revenue in 2006 was about 7 billion dollars, 1/3^rd that of Microsoft (up from 1/4^th in 2004), and is still gaining market share. Is Microsoft Vista motivating business to look more closely at Linux?

With the One Laptop Per Child (OLPC) initiative, a streamlined version of Fedora Core 6 will be placed in front of tens (or possibly hundreds) of millions of students worldwide. These students will learn Linux first. And Red Hat Enterprise Linux 5 is based on Fedora Core 6.

Security is another reason to move toward Linux. The U.S. National Security Agency has developed its own version of the Linux kernel to provide context-based security; RHEL has incorporated many of these improvements.

While there are Linux distributions available from a number of companies, Red Hat is far and away the market leader. Novell's acquisition of SUSE hasn't made a dent. Based on 2006 sales, Red Hat has apparently shrugged off the challenge of Oracle Linux (which is another "rebuild" of Red Hat Enterprise Linux). Incidentally, the RHCE was named #1 in CertCities.com's list of hottest certifications for 2006. Therefore, the RHCE provides the most credibility to you as a Linux professional.

The RHCT and RHCE exams are difficult. Available historical data suggests that less than 50 percent of first-time candidates pass the RHCE exam. But do not be intimidated. While there are no guarantees, this book can help you prepare for and pass the Red Hat Certified Technician and Red Hat Certified Engineer exams. And these same skills can help you in your career as a Linux administrator. Just remember, this book is not intended to be a substitute for Red Hat prep courses that I describe shortly.

To study for this exam, you should have a network of at least two Linux or Unix computers. (It's acceptable if these computers are on virtual machines such as VMware or Xen.) You need to install RHEL on at least one of these computers. That will allow you to configure Linux and test the results. After configuring a service, especially a network service, it's important to be able to check your work from another computer.