Red Hat Enterprise Linux 6 Administration E-Book

Sander van Vugt

• Herausgeber: John Wiley & Sons
• Kategorie: Wissenschaft und neue Technologien
• Sprache: Englisch
• Veröffentlichungsjahr: 2013

Seitenzahl: 996

Beschreibung

The definitive guide to administering a Red Hat Enterprise Linux 6 network Linux professionals who need a go-to guide on version 6 of Red Hat Enterprise Linux (RHEL) will find what they need in this comprehensive Sybex book. It covers RHEL administration in detail, including how to set up and manage web and mail services, use RHEL in enterprise environments, secure it, optimize storage, configure for virtualization and high availability, and much more. It also provides a great study aid for those preparing for either the RHCSA or RHCE certification exam. * Red Hat is the Linux market leader, and Red Hat administrators are in demand * This Sybex guide is a comprehensive resource on Red Hat Enterprise Linux administration and useful for those preparing for one of the Red Hat certification exams * Covers setting up and managing web and mail services, using RHEL in enterprise environments, securing RHEL, and optimizing storage to fit your environment * Explores advanced RHEL configurations, including virtualization and high availability Red Hat Enterprise Linux 6 Administration is the guide Linux professionals and Red Hat administrators need to stay current on the newest version.

Leseprobe

Table of Contents

Title Page

Copyright

Publisher's Note

Dedication

About the Author

Acknowledgments

Table of Exercises

Introduction

Who Should Read This Book?

What Is Covered in This Book?

How to Contact the Author

Part I: Getting Familiar with Red Hat Enterprise Linux

Chapter 1: Getting Started with Red Hat Enterprise Linux

Linux, Open Source, and Red Hat

Red Hat Enterprise Linux and Related Products

Installing Red Hat Enterprise Linux Server

Exploring the GNOME User Interface

Summary

Chapter 2: Finding Your Way on the Command Line

Working with the Bash Shell

Performing Basic File System Management Tasks

Piping and Redirection

Finding Files

Working with an Editor

Getting Help

Summary

Part II: Administering Red Hat Enterprise Linux

Chapter 3: Performing Daily System Administration Tasks

Performing Job Management Tasks

System and Process Monitoring and Management

Scheduling Jobs

Mounting Devices

Working with Links

Creating Backups

Managing Printers

Setting Up System Logging

Summary

Chapter 4: Managing Software

Understanding RPM

Understanding Meta Package Handlers

Installing Software with Yum

Querying Software

Extracting Files from RPM Packages

Summary

Chapter 5: Configuring and Managing Storage

Understanding Partitions and Logical Volumes

Creating Partitions

Creating File Systems

Mounting File Systems Automatically through fstab

Working with Logical Volumes

Creating Swap Space

Working with Encrypted Volumes

Summary

Chapter 6: Connecting to the Network

Understanding NetworkManager

Configuring Networking from the Command Line

Troubleshooting Networking

Setting Up IPv6

Configuring SSH

Configuring VNC Server Access

Summary

Part III: Securing Red Hat Enterprise Linux

Chapter 7: Working with Users, Groups, and Permissions

Managing Users and Groups

Using Graphical Tools for User and Group Management

Using External Authentication Sources

Understanding the Authentication Process

Understanding nsswitch

Managing Permissions

Summary

Chapter 8: Understanding and Configuring SELinux

Understanding SELinux

Selecting the SELinux Mode

Working with SELinux Context Types

Configuring SELinux Policies

Working with SELinux Modules

Setting Up SELinux with system-config-selinux

Troubleshooting SELinux

Summary

Chapter 9: Working with KVM Virtualization

Understanding the KVM Virtualization Architecture

Preparing Your Host for KVM Virtualization

Installing a KVM Virtual Machine

Managing KVM Virtual Machines

Understanding KVM Networking

Summary

Chapter 10: Securing Your Server with iptables

Understanding Firewalls

Setting Up a Firewall with system-config-firewall

Setting Up a Firewall with iptables

Advanced iptables Configuration

Configuring NAT

Summary

Chapter 11: Setting Up Cryptographic Services

Introducing SSL

Managing Certificates with openssl

Working with GNU Privacy Guard

Summary

Part IV: Networking Red Hat Enterprise Linux

Chapter 12: Configuring OpenLDAP

Understanding OpenLDAP

Configuring a Base OpenLDAP Server

Populating the OpenLDAP Database

Using OpenLDAP for Authentication

Summary

Chapter 13: Configuring Your Server for File Sharing

Configuring NFS4

Configuring Automount

Configuring Samba

Offering FTP Services

File Sharing and SELinux

Summary

Chapter 14: Configuring DNS and DHCP

Understanding DNS

Setting Up a DNS Server

Understanding DHCP

Setting Up a DHCP Server

Summary

Chapter 15: Setting Up a Mail Server

Using the Message Transfer Agent

Setting Up Postfix as an SMTP Server

Configuring Dovecot for POP and IMAP

Further Steps

Summary

Chapter 16: Configuring Apache on Red Hat Enterprise Linux

Configuring the Apache Web Server

Working with Virtual Hosts

Securing the Web Server with TLS Certificates

Configuring Authentication

Setting Up MySQL

Summary

Part V: Advanced Red Hat Enterprise Linux Configuration

Chapter 17: Monitoring and Optimizing Performance

Interpreting What's Going On: The top Utility

Analyzing CPU Performance

Analyzing Memory Usage

Monitoring Storage Performance

Understanding Network Performance

Optimizing Performance

Summary

Chapter 18: Introducing Bash Shell Scripting

Getting Started

Working with Variables and Input

Performing Calculations

Using Control Structures

Summary

Chapter 19: Understanding and Troubleshooting the Boot Procedure

Introduction to Troubleshooting the Boot Procedure

Configuring Booting with GRUB

Common Kernel Management Tasks

Configuring Service Startup with Upstart

Basic Red Hat Enterprise Linux Troubleshooting

Summary

Chapter 20: Introducing High-Availability Clustering

Understanding High-Availability Clustering

Configuring Cluster-Based Services

Installing the Red Hat High Availability Add-on

Creating Resources and Services

Configuring GFS2 File Systems

Summary

Chapter 21: Setting Up an Installation Server

Configuring a Network Server As an Installation Server

Setting Up a TFTP and DHCP Server for PXE Boot

Creating a Kickstart File

Summary

Appendix A: Hands-On Labs

Chapter 1: Getting Started with Red Hat Enterprise Linux

Chapter 2: Finding Your Way on the Command Line

Chapter 3: Performing Daily System Administration Tasks

Chapter 4: Managing Software

Chapter 5: Configuring and Managing Storage

Chapter 6: Connecting to the Network

Chapter 7: Working with Users, Groups, and Permissions

Chapter 8: Understanding and Configuring SELinux

Chapter 9: Working with KVM Virtualization

Chapter 10: Securing Your Server with iptables

Chapter 11: Setting Up Cryptographic Services

Chapter 12: Configuring Open LDAP

Chapter 13: Configuring Your Server for File Sharing

Chapter 14: Configuring DNS and DHCP

Chapter 15: Setting Up a Mail Server

Chapter 16: Configuring Apache on Red Hat Enterprise Linux

Chapter 17: Monitoring and Optimizing Performance

Chapter 18: Introducing Bash Shell Scripting

Chapter 19: Understanding and Troubleshooting the Boot Procedure

Chapter 20: Introducing High-Availability Clustering

Chapter 21: Setting Up an Installation Server

Appendix B: Answers to Hands-On Labs

Chapter 1: Getting Started with Red Hat Enterprise Linux

Chapter 2: Finding Your Way on the Command Line

Chapter 3: Performing Daily System Administration Tasks

Chapter 4: Managing Software

Chapter 5: Configuring and Managing Storage

Chapter 6: Connecting to the Network

Chapter 7: Working with Users, Groups, and Permissions

Chapter 8: Understanding and Configuring SELinux

Chapter 9: Working with KVM Virtualization

Chapter 10: Securing Your Server with iptables

Chapter 11: Setting Up Cryptographic Services

Chapter 12: Configuring OpenLDAP

Chapter 13: Configuring Your Server for File Sharing

Chapter 14: Configuring DNS and DCHP

Chapter 15: Setting Up a Mail Server

Chapter 16: Configuring Apache on Red Hat Enterprise Linux

Chapter 17: Monitoring and Optimizing Performance

Chapter 18: Introducing Bash Shell Scripting

Chapter 19: Understanding and Troubleshooting the Boot Procedure

Chapter 20: Introducing High-Availability Clustering

Chapter 21: Setting Up an Installation Server

Glossary

Index

Senior Acquisitions Editor: Jeff Kellum

Development Editor: Gary Schwartz

Technical Editors: Floris Meester, Erno de Korte

Production Editor: Rebecca Anderson

Copy Editor: Kim Wimpsett

Editorial Manager: Pete Gaughan

Production Manager: Tim Tate

Vice President and Executive Group Publisher: Richard Swadley

Vice President and Publisher: Neil Edde

Book Designer: Judy Fung and Bill Gibson

Proofreaders: Louise Watson and Jennifer Bennett, Word One New York

Indexer: J & J Indexing

Project Coordinator, Cover: Katherine Crocker

Cover Designer: Ryan Sneed

Cover Image: © Jacob Wackerhausen / iStockPhoto

Copyright © 2013 by John Wiley & Sons, Inc., Indianapolis, Indiana

Published simultaneously in Canada

ISBN: 978-1-118-30129-6

ISBN: 978-1-118-62045-8 (ebk.)

ISBN: 978-1-118-42143-7 (ebk.)

ISBN: 978-1-118-57091-3 (ebk.)

No part of this publication may be reproduced, stored in a retrieval system or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, scanning or otherwise, except as permitted under Sections 107 or 108 of the 1976 United States Copyright Act, without either the prior written permission of the Publisher, or authorization through payment of the appropriate per-copy fee to the Copyright Clearance Center, 222 Rosewood Drive, Danvers, MA 01923, [phone], fax [phone]. Requests to the Publisher for permission should be addressed to the Permissions Department, John Wiley & Sons, Inc., 111 River Street, Hoboken, NJ 07030, [phone], fax [phone], or online at http://www.wiley.com/go/permissions.

Limit of Liability/Disclaimer of Warranty: The publisher and the author make no representations or warranties with respect to the accuracy or completeness of the contents of this work and specifically disclaim all warranties, including without limitation warranties of fitness for a particular purpose. No warranty may be created or extended by sales or promotional materials. The advice and strategies contained herein may not be suitable for every situation. This work is sold with the understanding that the publisher is not engaged in rendering legal, accounting, or other professional services. If professional assistance is required, the services of a competent professional person should be sought. Neither the publisher nor the author shall be liable for damages arising herefrom. The fact that an organization or Web site is referred to in this work as a citation and/or a potential source of further information does not mean that the author or the publisher endorses the information the organization or Web site may provide or recommendations it may make. Further, readers should be aware that Internet Web sites listed in this work may have changed or disappeared between when this work was written and when it is read.

For general information on our other products and services or to obtain technical support, please contact our Customer Care Department within the U.S. at [phone], outside the U.S. at [phone] or fax [phone].

Wiley publishes in a variety of print and electronic formats and by print-on-demand. Some material included with standard print versions of this book may not be included in e-books or in print-on-demand. If this book refers to media such as a CD or DVD that is not included in the version you purchased, you may download this material at http://booksupport.wiley.com. For more information about Wiley products, visit www.wiley.com.

Library of Congress Control Number: 9781118301296

TRADEMARKS: Wiley, the Wiley logo, and the Sybex logo are trademarks or registered trademarks of John Wiley & Sons, Inc. and/or its affiliates, in the United States and other countries, and may not be used without written permission. Red Hat is a registered trademark of Red Hat, Inc. Linux is a registered trademark of Linus Torvalds. All other trademarks are the property of their respective owners. John Wiley & Sons, Inc. is not associated with any product or vendor mentioned in this book.

Dear Reader,

Thank you for choosing Red Hat Enterprise Linux 6 Administration: Real World Skills for Red Hat Administrators. This book is part of a family of premium-quality Sybex books, all of which are written by outstanding authors who combine practical experience with a gift for teaching.

Sybex was founded in 1976. More than 30 years later, we're still committed to producing consistently exceptional books. With each of our titles, we're working hard to set a new standard for the industry. From the paper we print on to the authors we work with, our goal is to bring you the best books available.

I hope you see all that reflected in these pages. I'd be very interested to hear your comments and get your feedback on how we're doing. Feel free to let me know what you think about this or any other Sybex book by sending me an email at [email protected]. If you think you've found a technical error in this book, please visit http://sybex.custhelp.com. Customer feedback is critical to our efforts at Sybex.

About the Author

Sander van Vugt is an author of more than 50 technical books. Most of these books are in his native language of Dutch. Sander is also a technical instructor who works directly for major Linux vendors, such as Red Hat and SUSE. He specializes in high availability and performance issues in Linux. He has also built up a lot of experience in securing servers with SELinux, especially on platforms that don't support it natively. Sander has applied his skills in helping many companies all over the world who are using Linux. His work has taken him to amazing places like Greenland, Utah, Malaysia, and more.

When not working, Sander likes to spend time with his two sons, Franck and Alex, and his beautiful wife, Florence. He also likes outdoor sports, in particular running, hiking, kayaking, and ice-skating. During these long hours of participating in sports, he thinks through the ideas for his next book and the projects on which he is currently working, which makes the actual writing process a lot easier and the project go more smoothly.

Acknowledgments

Books of this size and depth succeed because of all the hard work put in by a team of professionals. I'm grateful for all the hard work put in by several people at Sybex on this project. Gary Schwartz was a great developmental editor. He helped keep things on track and provided excellent editorial guidance. The technical editors, Floris Meester and Erno de Korte, provided insightful input throughout the book. I appreciated the meticulous attention to detail provided by Rebecca Anderson, the production editor for this book. Last, but certainly not least, I want to thank Jeff Kellum, the acquisitions editor, for having the faith in me to write this book for Sybex.

Table of Exercises

Exercise 1.1

  Installing Linux on Your Machine

Exercise 2.1

  Discovering the Use of Pipes

Exercise 2.2

  Using grep in Pipes

Exercise 2.3

  Redirecting Output to a File

Exercise 2.4

  Using Redirection of STDIN

Exercise 2.5

  Separating STDERR from STDOUT

Exercise 2.6

  Replacing Text with vi

Exercise 2.7

  Working with man -k

Exercise 3.1

  Managing Jobs

Exercise 3.2

  Managing Processes with ps and kill

Exercise 3.3

  Using nice to Change Process Priority

Exercise 3.4

  Running a Task from cron

Exercise 3.5

  Mounting a USB Flash Drive

Exercise 3.6

  Creating Links

Exercise 3.7

  Archiving and Extracting with tar

Exercise 3.8

  Configuring Logging

Exercise 4.1

  Setting Up Your Own Repository

Exercise 4.2

  Working with yum

Exercise 4.3

  Installing Software with yum

Exercise 4.4

  Finding More Information About Installed Software

Exercise 4.5

  Extracting Files from RPM Packages

Exercise 5.1

  Creating Partitions

Exercise 5.2

  Creating a File System

Exercise 5.3

  Setting a File System Label

Exercise 5.4

  Mounting Devices Through /etc/fstab

Exercise 5.5

  Fixing /etc/fstab Problems

Exercise 5.6

  Creating LVM Logical Volumes

Exercise 5.7

  Extending a Logical Volume

Exercise 5.8

  Extending a Volume Group

Exercise 5.9

  Reducing a Logical Volume

Exercise 5.10

  Managing Snapshots

Exercise 5.11

  Creating a Swap File

Exercise 5.12

  Creating an Encrypted Device

Exercise 5.13

  Mounting an Encrypted Device Automatically

Exercise 6.1

  Working with Services

Exercise 6.2

  Configuring a Network Interface with ip

Exercise 6.3

  Setting a Fixed IPv6 Address.

Exercise 6.4

  Enabling and Testing the SSH Server.

Exercise 6.5

  Securing the SSH Server

Exercise 6.6

  Setting Up Key-Based Authentication

Exercise 6.7

  Setting Up Key-Based SSH Authentication Protected with a Passphrase

Exercise 6.8

  Setting Up a VNC Server

Exercise 7.1

  Creating Users

Exercise 7.2

  Creating and Managing Groups

Exercise 7.3

  Logging in Using an LDAP Directory Server

Exercise 7.4

  Configuring PAM.

Exercise 7.5

  Setting Permissions for Users and Groups

Exercise 7.6

  Working with Special Permissions

Exercise 7.7

  Refining Permissions Using ACLs

Exercise 8.1

  Displaying SELinux Type Context

Exercise 8.2

  Switching Between SELinux Modes

Exercise 8.3

  Applying File Contexts

Exercise 8.4

  Working with SELinux Booleans

Exercise 8.5

  Enabling sealert Message Analysis

Exercise 9.1

  Determining Whether Your Server Meets KVM Virtualization Requirements

Exercise 9.2

  Preparing Your Server to Function as a KVM Hypervisor

Exercise 9.3

  Installing a KVM Virtual Machine

Exercise 9.4

  Working with Virtual Machine Manager

Exercise 9.5

  Changing a VM Hardware Configuration

Exercise 9.6

  Exploring virsh

Exercise 9.7

  Changing Virtual Machine Networking

Exercise 9.8

  Reconfiguring Networking in a Virtual Machine

Exercise 10.1

   Allowing Basic Services Through the Firewall

Exercise 10.2

   Configuring Port Forwarding

Exercise 10.3

   Building a Netfilter Firewall

Exercise 10.4

   Setting Up iptables Logging

Exercise 10.5

   Configuring NAT

Exercise 11.1

   Creating a Self-signed Certificate

Exercise 11.2

   Creating and Exchanging GPG Keys

Exercise 11.3

   Encrypting and Decrypting Files

Exercise 11.4

   Signing RPM Packages with GPG Keys

Exercise 12.1

   Changing the Base LDAP Configuration

Exercise 12.2

   Creating the Base LDAP Directory Structure

Exercise 12.3

   Installing the Schema File for DHCP

Exercise 12.4

   Creating an LDAP User

Exercise 12.5

   Adding an LDAP Group

Exercise 13.1

   Creating NFS Shares

Exercise 13.2

   Mounting an NFS Share

Exercise 13.3

   Using /net to Access an NFS Share

Exercise 13.4

   Creating an Automount Indirect Map

Exercise 13.5

   Creating an Automount Configuration for Home Directories

Exercise 13.6

   Setting Up a Samba Server

Exercise 13.7

   Setting SELinux Labels for Samba

Exercise 13.8

   Mounting a Samba Share Using /etc/fstab

Exercise 13.9

   Enabling an Anonymous FTP Server

Exercise 14.1

   Configuring a Cache-Only Name Server

Exercise 14.2

   Setting Up a Primary DNS Server

Exercise 14.3

   Setting Up a DHCP Server

Exercise 15.1

   Getting to Know Mutt

Exercise 15.2

   Sending a Message to an External User

Exercise 15.3

   Opening Your Mail Server for External Mail

Exercise 15.4

   Creating a Base Dovecot Configuration

Exercise 16.1

   Creating a Basic Website

Exercise 16.2

   Configuring SELinux for Apache

Exercise 16.3

   Installing and Using the Apache Documentation

Exercise 16.4

   Configuring Virtual Hosts

Exercise 16.5

   Setting Up an SSL-Based Virtual Host

Exercise 16.6

   Setting Up a Protected Web Server

Exercise 16.7

   Installing MySQL and Creating User Accounts

Exercise 17.1

   Monitoring Buffer and Cache Memory

Exercise 17.2

   Analyzing CPU Performance

Exercise 17.3

   Analyzing Kernel Memory

Exercise 17.4

   Exploring I/O Performance

Exercise 17.5

   Configuring Huge Pages

Exercise 17.6

   Changing Scheduler Parameters

Exercise 18.1

   Creating Your First Shell Script

Exercise 18.2

   Creating a Script That Works with Arguments

Exercise 18.3

   Referring to Command-Line Arguments in a Script

Exercise 18.4

   Counting Arguments

Exercise 18.5

   Asking for Input with read

Exercise 18.6

   Working with Pattern-Matching Operators

Exercise 18.7

   Applying Pattern Matching on a Date String

Exercise 18.8

   Example Script Using case

Exercise 18.9

   Checking Whether the IP Address Is Still There

Exercise 19.1

   Adding a GRUB Boot Password

Exercise 19.2

   Booting with Alternative Boot Options

Exercise 19.3

   Manually Starting GRUB

Exercise 19.4

   Applying Kernel Module Options

Exercise 19.5

   Starting Your Server in Minimal Mode

Exercise 19.6

   Resetting the Root Password

Exercise 19.7

   Starting a Rescue System

Exercise 20.1

   Creating a Bond Device

Exercise 20.2

   Creating an iSCSI Target Configuration

Exercise 20.3

   Connecting to an iSCSI Target

Exercise 20.4

   Creating an /etc/hosts File

Exercise 20.5

   Creating a Cluster with Conga

Exercise 20.6

   Creating a Quorum Disk

Exercise 20.7

   Creating an HA Service for Apache

Exercise 20.8

   Creating a GFS File System

Exercise 21.1

   Setting Up the Network Installation Server

Exercise 21.2

   Configuring the TFTP Server for PXE Boot

Exercise 21.3

   Performing a Virtual Machine Network Installation Using a Kickstart File

Introduction

Red Hat is the number-one Linux vendor on the planet. Even though official figures have never been released, as the first open source, one-billion dollar company, Red Hat is quite successful in enterprise Linux. More and more companies are installing Red Hat servers every day, and with that, there's an increasing need for Red Hat skills. That is why I wrote this book.

This book is a complete guide that contains real-world examples of how Red Hat Enterprise Linux should be administered. It targets a broad audience of both beginning and advanced Red Hat Enterprise Linux administrators who need a reference guide to learn how to perform complicated tasks.

This book was also written as a study guide, which is why there are many exercises included in the book. Within each chapter, you'll find step-by-step exercises that lead you through specific procedures. Also, in Appendix A at the end of the book, you'll find lab exercises that help you wrap up everything you've learned in the chapter.

Red Hat offers two certifications that are relevant for system administrators: Red Hat Certified System Administrator (RHCSA) and Red Hat Certified Engineer (RHCE). This book does not prepare for either the Red Hat RHCSA or RHCE exams, but it does cover most of the objectives of both exams. For those interested in taking RHCSA and RHCE exams, it is recommended that you also attend a Red Hat training course, where the learner risks meeting the author of this book who has been a Red Hat Certified Instructor for many years now.

Who Should Read This Book?

This book was written for Red Hat administrators. The book is for beginning administrators as well as those who already have a couple of years of experience working with Red Hat systems. For the advanced administrators, it is written as a reference guide that helps them set up services such as web servers, DNS and DHCP, clustering, and more. It also contains advanced information, such as a long chapter on performance optimization.

What You Need

To work with this book, you need a dedicated computer on which you can install Red Hat Enterprise Linux. If this is not feasible, a virtual machine can be used as an alternative, however this is absolutely not recommended, as you won't be able to do all the exercises on virtualization. To install Red Hat Enterprise Linux and use it as a host for KVM virtualization, make sure that your computer meets the following minimum criteria:

64-bit CPU with support for virtualization.

At least 2GB of RAM is recommended. (It will probably work with 1GB, but this is not recommended.)

A DVD drive.

A hard disk that is completely available and at least 40GB in size.

A network card and connection to a network switch.

What Is Covered in This Book?

Red Hat Linux Enterprise 6 Administration is organized to provide the knowledge that you'll need to administer Red Hat Enterprise Linux 6. It includes the following chapters:

Part I: Getting Familiar with Red Hat Enterprise Linux

Chapter 1, “Getting Started with Red Hat Enterprise Linux”  This chapter introduces Red Hat Enterprise Linux and explains its particulars. You'll also learn about the value added by this commercial Linux distribution as compared to free Linux distributions. In the second part of this chapter, you'll learn how to install Red Hat Enterprise Linux. You'll also get a quick introduction to the workings of the graphical user interface.

Chapter 2, “Finding Your Way on the Command Line”  This chapter introduces you to working on the command line, the most important interface you'll use to manage your Red Hat Enterprise Linux server.

Part II: Administering Red Hat Enterprise Linux

Chapter 3, “Performing Daily System Administration Tasks”  In this chapter, you'll learn about some common system administration tasks. This includes mounting and unmounting file systems, setting up and managing a printing environment, and scheduling jobs with cron. You'll also learn how to do process administration and make backups.

Chapter 4, “Managing Software”  In this chapter, you'll learn how to install software. You'll also read how to manage software, which includes querying software packages to find out everything you need to know about installed software. You'll also read how to set up the repositories that you'll need for an easy way to install and manage software.

Chapter 5, “Configuring and Managing Storage”  This chapter teaches you how to set up storage. It includes information about managing partitions, logical volumes, and encrypted volumes. You'll also learn how to set up automatic mounting of volumes through fstab and how to create and manage swap space.

Chapter 6, “Connecting to the Network”  Here you'll learn how to connect your server to the network. The chapter addresses setting up the network interface, both from the command line and from the configuration files. You'll set up normal network connections, and you will also learn how to create a bonded network interface. Finally, you'll learn how to test your network using common utilities such as ping and dig.

Part III: Securing Red Hat Enterprise Linux

Chapter 7, “Working with Users, Groups, and Permissions”  To manage who can do what on your system, you'll need to create users and put them in groups. In this chapter, you'll learn how to do that and how to add users to primary and secondary groups. You'll also learn how to work with basic and advanced permissions and set up access control lists.

Chapter 8, “Understanding and Configuring SELinux”  This chapter teaches you how to make your Red Hat Enterprise Linux server really secure using SELinux. You'll learn about the different modes that are available and how to set file system context labels and Booleans to tune SELinux exactly to your needs.

Chapter 9, “Working with KVM Virtualization”  Red Hat Enterprise Linux offers virtualization capabilities by default. In this chapter, you'll learn how to set these up using KVM virtualization. You'll learn what your server needs to be a KVM host, and you'll read how to create and manage virtual machines.

Chapter 10, “Securing Your Server with iptables”  iptables is a kernel-provided firewall, which blocks or allows access to services configured to listen at specific ports. In this chapter, you'll learn how to set up the iptables firewall from the command line.

Chapter 11, “Setting Up Cryptographic Services”  In this chapter, you'll learn how to set up cryptographic services on Red Hat Enterprise Linux. You'll learn how to configure SSL certificates and have them signed by a certificate authority. You'll also learn how to use GPG for file and email encryption and security.

Part IV: Networking Red Hat Enterprise Linux

Chapter 12, “Configuring OpenLDAP”  If you really need to manage more than just a few users, using a directory service such as OpenLDAP can be handy. In this chapter, you'll learn how to set up OpenLDAP on your server. You'll also learn how to add user objects to the OpenLDAP server and how to configure your server to authenticate on OpenLDAP.

Chapter 13, “Configuring Your Server for File Sharing”  This chapter teaches you how to set up your server for file sharing. You'll learn about common file sharing solutions, such as FTP, NFS, and Samba. You'll also learn how to connect to servers offering these services from Red Hat Enterprise Linux.

Chapter 14, “Configuring DNS and DHCP”  In this chapter, you'll read how to set up a Dynamic Host Configuration Protocol (DHCP) server to automate providing computers in your network with IP addresses and related information. You'll also learn how to set up Domain Name System (DNS) on your servers, configuring them as primary and secondary servers, as well as cache-only servers.

Chapter 15, “Setting Up a Mail Server”  Postfix is the default mail server on Red Hat Enterprise Linux. In this chapter, you'll learn how to set up Postfix to send and receive email on your server. You'll also learn how to set up Dovecot to make email accessible for clients using POP or IMAP.

Chapter 16, “Configuring Apache on Red Hat Enterprise Linux”  In this chapter, you'll learn how to set up Apache on your server. You'll learn how to configure basic hosts, virtual hosts, and SSL secured hosts. The chapter also teaches you how to set up file-based or LDAP-based user authentication.

Part V: Advanced Red Hat Enterprise Linux Configuration

Chapter 17, “Monitoring and Optimizing Performance”  For your server to function properly, it is important that it performs well. In this chapter, you'll learn how to analyze server performance and how to fix it if there are problems. You'll also read some hints about setting up the server in a way that minimizes the chance of having performance-related problems.

Chapter 18, “Introducing Bash Shell Scripting”  Every Linux administrator should at least know the basics of shell scripting. This chapter teaches you how it works. You'll learn how to set up a shell script and how to use common shell scripting structures to handle jobs in the most ideal manner.

Chapter 19, “Understanding and Troubleshooting the Boot Procedure”  Many tasks are executed sequentially when your server boots. In this chapter, you'll learn about everything that happens during server startup, including GRUB configuration and the way Upstart is used. You'll also learn how to troubleshoot common issues that you may encounter while booting your server.

Chapter 20, “Introducing High-Availability Clustering”  In a mission-critical environment, the Red Hat High Availability add-on can be a valuable addition to your datacenter. In this chapter, you'll learn how to design and set up high availability on Red Hat Enterprise Linux.

Chapter 21, “Setting Up an Installation Server”  In a datacenter environment, you don't want to set up every server manually. This is why it makes sense to set up an installation server. This chapter teaches you how to automate the installation of Red Hat Enterprise Linux completely. It includes setting up a network installation server and configuring a TFTP server that hands out boot images to clients that perform a PXE boot. You'll also learn how to create a kickstart configuration file, which passes all parameters that are to be used for the installation.

Glossary  This contains definitions of the relevant vocabulary terms in this book.

How to Contact the Author

If you want to provide feedback about the contents of this book or if you're seeking a helping hand in setting up an environment or fixing problems, you can contact me directly. The easiest way to get in touch with me is by sending an email to [email protected]. You can also visit my website at www.sandervanvugt.com. If you're interested in the person behind the book, you're also more than welcome to visit my hobby site at www.sandervanvugt.org.

Sybex strives to keep you supplied with the latest tools and information you need for your work. Please check their website at www.sybex.com, where we'll post additional content and updates that supplement this book if the need arises. Enter search terms in the Search box (or type the book's ISBN: 978-1-118-30129-6), and click Go to get to the book's update page.

Part I

Getting Familiar with Red Hat Enterprise Linux

Chapter 1

Getting Started with Red Hat Enterprise Linux

Topics covered in this chapter:

Linux, Open Source, and Red Hat

Red Hat Enterprise Linux and Related Products

Installing Red Hat Enterprise Linux Server

Exploring the GNOME User Interface

Red Hat Enterprise Linux is in use at most Fortune 500 companies, and it takes care of mission-critical tasks in many of them. This chapter introduces Red Hat Enterprise Linux. It begins with a brief history, where you'll learn about Linux in general and the role of Red Hat in the Linux story. Following that, it provides an overview of Red Hat Enterprise Linux (RHEL) and its related products. Finally, you'll learn how to install RHEL so that you can start building your RHEL skills.

Linux, Open Source, and Red Hat

If you want to work with Red Hat, it helps to understand a little bit about its background. In this introduction, you'll learn about the rise of UNIX, the Linux kernel and open source, and the founding of Red Hat.

Origins of Linux

The late 1960s and early 1970s were the dawn of the modern computing era. It was the period of proprietary stacks, where a vendor would build a “closed” computer system and create the operating software to run on it. Computers were extremely expensive and rare among businesses. In that period, scientists were still looking for the best way to operate a computer, and that included developing the best programming language. It was normal for computer programmers to address the hardware directly, using very complex assembly programming languages.

An important step forward was the development of the general-purpose programming language C by Dennis Richie at Bell Telephone Laboratories in 1969. This language was developed for use with the UNIX operating system.

The UNIX operating system was the first operating system where people from different companies tried to work together to build instead of competing with each other, keeping their efforts secret. This spirit brought UNIX to scientific, government, and higher-education institutions. There it also became the basis for the rise of another phenomenon, the Internet Protocol (IP) and the Internet. One of the huge contributors to the success of UNIX was the spirit of openness of the operating system. Everyone could contribute to it, and the specifications were freely available to anyone.