Chapter 11: Operational Administration Recovery and Security

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Overview

The themes of this chapter are security and recovery. These are two critical concepts for the Red Hat exams. This continues the discussion of system security started in the last chapter, with a look at secure ways to run certain network services and a Red Hat Enterprise Linux-specific way of configuring file security.

This chapter includes a description of setting up security with groups. You can set up special groups on an RHEL 3 computer. You can set up a common directory for the users in these groups.

Inside The Exam

Installation and Configuration

Part of this chapter can help you with the skills you need on the Red Hat Installation and Configuration exams. One of the basic foundations of Linux is that most services have their own special accounts. While the User Private Group scheme isn't explicitly mentioned in the Red Hat Exam Prep guide, it is part of the prep courses (RH133, RH300) for both RHCT and RHCE exams. The RHCT prep course does also cover anacron and tmpwatch, so it's possible that you'll see those services on both exams.

Troubleshooting and System Maintenance

When you read this chapter, focus on the requirements associated with the Red Hat Troubleshooting and System Maintenance exams. Perhaps the most important Linux administrative skill is knowing how to rescue a damaged system. RHCTs need to know how to boot from the GRUB menu into different runlevels. RHCEs also need to know how to rescue a system using the first RHEL 3 installation CD. If you're planning to take the Red Hat exams, learn how to diagnose boot problems. Create a few more of your own, and learn the symptoms. It may help you avoid frustration and solve problems quickly during the RHCE Troubleshooting and System Maintenance exam. Finally, as Logical Volume Management is becoming more important on Red Hat systems, you need to know how to add, remove, and resize logical volumes on the RHCE exam.

Next, you'll learn about two different administrative processes. The anacron service can help you make sure that cron jobs that are missed when your RHEL 3 computer is powered down are run. The tmpwatch script is a standard cron job that can help you maintain your temporary directories.

You'll also examine one of the most fundamental fears of any systems administrator: what to do when a system will not boot. When the inevitable happens, knowing the right things to look for and having some tricks up your sleeve may possibly help you avoid a potential nightmare and a major loss of service for your users. Understanding these tools is fundamental to getting through troubleshooting scenarios on the Red Hat exams.

Finally, you'll look at how to manage and extend the Logical Volumes that you created in Chapters 2 and 3. With this skill in hand, you can expand full volumes such as the /home directory, as needed.

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