RHCSA/RHCE Red Hat Linux certification study guide : (exams EX200 & EX300)

930 Pages·2016·48.18 MB·English

by  Jang

®
RHCSA/RHCE
Red Hat® Linux® Certification
Study Guide, Seventh Edition
(Exams EX200 & EX300)
Michael Jang
Alessandro Orsaria
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RHCSA/RHCE® Red Hat® Linux® Certification Study Guide, Seventh Edition (Exams EX200 & EX300)
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ABOUT THE AUTHORS
Michael Jang (RHCE, LPIC-2, UCP, LCP, Linux+, MCP) is currently a Senior Technical
Writer for ForgeRock. His experience with computers goes back to the days of jumbled
punch cards. He has written other books on Linux certification, including LPIC-1 in
Depth, Mike Meyers’ Linux+ Certification Passport, and Sair GNU/Linux Installation and
Configuration Exam Cram. His other Linux books include Linux Annoyances for Geeks,
Linux Patch Management, and Mastering Fedora Core Linux 5. He has also written or
contributed to books on Microsoft operating systems, including MCSE Guide to Microsoft
Windows 98 and Mastering Windows XP Professional, Second Edition.
Alessandro Orsaria (RHCE, RHCA, CCIE x 2) is an IT professional with more than 15
years’ experience in the industry. He has authored articles for technical Linux magazines
and is currently employed by a global equity hedge fund as an IT Infrastructure Architect.
Alessandro is Red Hat RHCE and RHCA certified and has achieved two Cisco CCIE
certifications in Routing & Switching and Datacenter. He holds an MBA from Imperial
College of London and a degree in physics.
About the Technical Editor
Alex Davies works for a proprietary trading firm, where he is responsible for Linux systems
and manages a team of Linux engineers across Chicago, New York, London, and Singapore.
Alex is the author of MySQL Clustering and MySQL High Availability Cookbook. Earlier
in his career he was both RHCE and RHCA certified and received the RHCE of the Year
award in 2009 from Red Hat. Alex also holds a degree in economics from the University of
Durham.
CONTENTS AT A GLANCE
1 Prepare for Red Hat Hands-on Certifications ................................. 1
2 Virtual Machines and Automated Installations ............................... 55
3 Fundamental Command-Line Skills ............................................. 115
4 RHCSA-Level Security Options .................................................. 175
5 The Boot Process .................................................................... 241
6 Linux Filesystem Administration ................................................. 285
7 Package Management .............................................................. 343
8 User Administration ................................................................ 395
9 RHCSA-Level System Administration Tasks .................................. 443
10 A Security Primer ................................................................... 479
11 System Services and SELinux ..................................................... 537
12 RHCE Administrative Tasks ...................................................... 579
13 Network Services: DNS, SMTP, iSCSI, and NTP ............................. 631
14 The Apache Web Server ........................................................... 679
15 The Samba File Server .............................................................. 733
16 NFS Secured with Kerberos ....................................................... 773
17 The MariaDB Server ................................................................ 807
A Prepare a System for the Sample Exams ........................................ 843
B Sample Exam 1: RHCSA ........................................................... 847
C Sample Exam 2: RHCSA ........................................................... 851
v
vi RHCSA/RHCE Red Hat Linux Certification Study Guide
D Sample Exam 3: RHCE Sample Exam 1 ......................................... 855
E Sample Exam 4: RHCE Sample Exam 2 ......................................... 861
F About the DVD ...................................................................... 865
Glossary ............................................................................... 867
Index ................................................................................... 883
CONTENTS
Acknowledgments ..................................................................... xxv
Preface ................................................................................... xxvii
Introduction ............................................................................ xxxviii
1 Prepare for Red Hat Hands-on Certifications ................. 1
The RHCSA and RHCE Exams ................................................... 4
The Exam Experience ................................................... 5
The RHCSA Exam ....................................................... 5
The RHCE Exam ......................................................... 6
If You’re Studying “Just” for the RHCSA Exam ..................... 6
Evolving Requirements .................................................. 6
Basic Hardware Requirements ................................................... 7
Hardware Compatibility ................................................ 7
Architectures .............................................................. 8
RAM Requirements ..................................................... 8
Hard Drive Options ...................................................... 9
Networking ................................................................ 9
Virtual Machine Options ............................................... 10
Get Red Hat Enterprise Linux .................................................... 11
Purchase a Subscription ................................................ 11
Get an Evaluation Copy ................................................. 12
Third-party Rebuilds .................................................... 12
Check the Download .................................................... 13
Installation Requirements ......................................................... 13
You Won’t Start from Scratch .......................................... 14
The Advantages of Network Installation ............................ 14
Red Hat and Virtual Machines ........................................ 15
Virtual and Physical Systems ........................................... 15
A Pre-installed Environment for Practice Labs .................... 15
System Roles .............................................................. 16
Installation Options ................................................................ 18
Boot Media ................................................................ 18
CD/DVD or Boot USB Starts Installation ........................... 19
Basic Installation Steps .................................................. 20
vii
viii RHCSA/RHCE Red Hat Linux Certification Study Guide
The Installation Perspective on Partitions .......................... 25
Partition Creation Exercise ............................................. 28
Exercise 1-1: Partitioning During Installation ................... 30
Wow, Look at All That Software! ...................................... 32
Baseline Packages ........................................................ 34
Package Groups .......................................................... 34
During the Installation .................................................. 35
System Setup Options .............................................................. 36
Initial Setup and Firstboot .............................................. 37
Default Security Settings ............................................... 37
Special Setup Options for Virtual Machines ........................ 38
Configure Default File Sharing Services ........................................ 39
Mount and Copy the Installation DVD .............................. 40
Set Up a Default Configuration Apache Server .................... 40
Exercise 1-2: Configure Apache as an Installation Server ..... 42
Share Copied Files via FTP Server .................................... 43
Certification Summary .................................................. 45
✓
Two-Minute Drill ........................................................ 46
Q&A Self Test .................................................................... 48
Lab Questions ............................................................ 49
Self Test Answers ......................................................... 52
Lab Answers .............................................................. 53
2 Virtual Machines and Automated Installations .............. 55
Configure KVM for Red Hat ...................................................... 56
Why Virtual Machines .................................................. 57
If You Have to Install KVM ............................................. 58
The Right KVM Modules ............................................... 59
Configure the Virtual Machine Manager ............................ 60
Configuration by Hypervisor .......................................... 61
Virtual Networks on a Hypervisor .................................... 62
Exercise 2-1: Create a Second Virtual Network ................. 63
Configure a Virtual Machine on KVM .......................................... 68
Configure a Virtual Machine on KVM ............................... 68
Exercise 2-2: Add Virtual Hard Drives ............................ 73
KVM Configuration Files ............................................... 75
Control Virtual Machines from the Command Line .............. 76
Automated Installation Options ................................................. 80
Kickstart Concepts ....................................................... 81
Set Up Local Access to Kickstart ...................................... 81
Set Up Network Access to Kickstart ................................. 83
Contents ix
Sample Kickstart File .................................................... 83
Exercise 2-3: Create and Use a Sample Kickstart File .......... 89
The Kickstart Configurator ............................................ 90
Administration with the Secure Shell and Secure Copy ..................... 95
Configure an SSH Client ................................................ 95
Command-Line Access ................................................. 96
More SSH Command-Line Tools ..................................... 97
Graphical Secure Shell Access ......................................... 97
Consider Adding These Command-Line Tools ............................... 98
Checking Ports with telnet ............................................. 99
Checking Ports with nmap ............................................. 100
Configure an E-mail Client ............................................. 100
The Use of Text and Graphical Browsers ............................ 102
Using lftp to Access URLs .............................................. 103
Certification Summary .................................................. 105
✓
Two-Minute Drill ........................................................ 105
Q&A Self Test .................................................................... 107
Lab Questions ............................................................ 108
Self Test Answers ......................................................... 110
Lab Answers .............................................................. 111
3 Fundamental Command-Line Skills ............................ 115
Shells ................................................................................... 118
Other Shells ............................................................... 119
Virtual Terminals ......................................................... 119
GUI Shell Interfaces ..................................................... 120
Differences Between Regular and Administrative Users ......... 121
Text Streams and Command Redirection ........................... 121
Standard Command-Line Tools .................................................. 122
File and Directory Concepts ........................................... 123
File Lists and ls ............................................................ 126
File-Creation Commands ............................................... 127
Wildcards .................................................................. 130
File Searches .............................................................. 130
The Management of Text Files ................................................... 131
Commands to Read Text Streams ..................................... 132
Commands to Process Text Streams ................................. 134
Edit Text Files at the Console .......................................... 137
Exercise 3-1: Using vi to Create a New User ..................... 139
If You Don’t Like vi ....................................................... 141
Edit Text Files in the GUI ............................................... 141
x RHCSA/RHCE Red Hat Linux Certification Study Guide
Local Online Documentation ..................................................... 142
When You Need Help ................................................... 142
A Variety of man Pages ................................................. 143
The info Manuals ........................................................ 145
Detailed Documentation in /usr/share/doc ......................... 146
A Networking Primer .............................................................. 146
IPv4 Networks ............................................................ 146
Networks and Routing .................................................. 147
Tools and Commands ................................................... 148
Network Configuration and Troubleshooting ................................. 154
Network Configuration Files ........................................... 155
Network Configuration Tools ......................................... 158
Exercise 3-2: Configure a Network Card ......................... 161
Configure Name Resolution ........................................... 164
Hostname Configuration Files ......................................... 165
Hostname Configuration Options .................................... 166
Certification Summary .................................................. 167
✓
Two-Minute Drill ........................................................ 168
Q&A Self Test .................................................................... 170
Lab Questions ............................................................ 171
Self Test Answers ......................................................... 172
Lab Answers .............................................................. 173
4 RHCSA-Level Security Options .................................. 175
Basic File Permissions .............................................................. 178
File Permissions and Ownership ...................................... 178
Commands to Change Permissions and Ownership .............. 181
Basic User and Group Concepts ...................................... 184
Access Control Lists and More ................................................... 186
The getfacl Command ................................................... 186
Make a Filesystem ACL Friendly ...................................... 187
Manage ACLs on a File ................................................. 188
Configure a Directory for ACLs ....................................... 190
Configure Default ACLs ................................................ 191
ACLs and Masks ......................................................... 192
Exercise 4-1: Use ACLs to Deny a User ........................... 192
NFS Shares and ACLs ................................................... 193
Basic Firewall Control .............................................................. 195
Standard Ports ............................................................ 196
A Focus on iptables ...................................................... 196
Keep That Firewall in Operation ...................................... 198