Red Hat RHCSA 8 Cert Guide

Sander van Vugt is an independent Linux trainer, author, and consultant living in the Netherlands. Sander is the author of the best-selling Red Hat Certified System Administrator (RHCSA) Complete Video Course and the Red Hat Certified Engineer (RHCE) Complete Video Course. He has also written numerous books about different Linux-related topics and many articles for Linux publications around the world. Sander has been teaching Red Hat, Linux+, and LFCS classes since 1994. As a consultant, he specializes in Linux high-availability solutions and performance optimization. You can find more information about Sander on his website at http://www.sandervanvugt.com. For more information about RHCSA certification and additional resources, visit the author’s Red Hat Certification page at http://www.rhatcert.com/.

Introduction xxviii
Part I: Performing Basic System Management Tasks
Chapter 1 Installing Red Hat Enterprise Linux 3
“Do I Know This Already?” Quiz 3
Foundation Topics 6
Preparing to Install Red Hat Enterprise Linux 6
What Is Red Hat Enterprise Linux 8 Server? 6
Getting the Software 7
Using Red Hat Enterprise Linux 7
Using CentOS 7
Other Distributions 8
Understanding Access to Repositories 8
Setup Requirements 9
Cert Guide Environment Description 9
Performing a Manual Installation 10
Summary 24
Exam Preparation Tasks 25
End-of-Chapter Lab 26
Chapter 2 Using Essential Tools 29
“Do I Know This Already?” Quiz 29
Foundation Topics 32
Basic Shell Skills 32
Understanding Commands 32
Executing Commands 32
I/O Redirection 34
Using Pipes 36
History 37
Bash Completion 39
Editing Files with vim 39
Understanding the Shell Environment 42
Understanding Variables 42
Recognizing Environment Configuration Files 43
Using /etc/motd and /etc/issue 43
Finding Help 44
Using --help 44
Using man 45
Finding the Right man Page 46
Updating mandb 47
Using info 48
Using /usr/share/doc Documentation Files 49
Summary 50
Exam Preparation Tasks 50
End-of-Chapter Lab 51
Chapter 3 Essential File Management Tools 53
“Do I Know This Already?” Quiz 53
Foundation Topics 56
Working with the File System Hierarchy 56
Defining the File System Hierarchy 56
Understanding Mounts 57
Managing Files 61
Working with Wildcards 62
Managing and Working with Directories 62
Working with Absolute and Relative Pathnames 63
Listing Files and Directories 64
Copying Files and Directories 65
Moving Files and Directories 66
Deleting Files and Directories 66
Using Links 68
Understanding Hard Links 68
Understanding Symbolic Links 69
Creating Links 69
Removing Links 70
Working with Archives and Compressed Files 71
Managing Archives with tar 72
Creating Archives with tar 72
Monitoring and Extracting tar Files 73
Using Compression 74
Summary 75
Exam Preparation Tasks 75
End-of-Chapter Lab 77
Chapter 4 Working with Text Files 81
“Do I Know This Already?” Quiz 81
Foundation Topics 84
Using Common Text File–Related Tools 84
Doing More with less 84
Showing File Contents with cat 85
Displaying the First or Last Lines of a File with head and tail 86
Filtering Specific Columns with cut 87
Sorting File Contents and Output with sort 87
Counting Lines, Words, and Characters with wc 88
A Primer to Using Regular Expressions 89
Using Line Anchors 90
Using Escaping in Regular Expressions 90
Using Wildcards and Multipliers 91
Using grep to Analyze Text 92
Working with Other Useful Text Processing Utilities 93
Summary 94
Exam Preparation Tasks 95
End-of-Chapter Lab 9
Chapter 5 Connecting to Red Hat Enterprise Linux 8 99
“Do I Know This Already?” Quiz 99
Foundation Topics 102
Working on Local Consoles 102
Logging In to a Local Console 102
Switching Between Terminals in a Graphical Environment 103
Working with Multiple Terminals in a Nongraphical Environment 104
Understanding Pseudo Terminal Devices 106
Booting, Rebooting, and Shutting Down Systems 106
Using SSH and Related Utilities 108
Accessing Remote Systems Using SSH 108
Using Graphical Applications in an SSH Environment 111
Securely Transferring Files Between Systems 111
Using scp to Securely Copy Files 112
Using sftp to Securely Transfer Files 112
Using rsync to Synchronize Files 113
Configuring Key-Based Authentication for SSH 114
Using Passphrases or Not? 114
Using the screen Command 115
Summary 117
Exam Preparation Tasks 117
End-of-Chapter Labs 118
Chapter 6 User and Group Management 121
“Do I Know This Already?” Quiz 121
Foundation Topics 124
Understanding Different User Types 124
Users on Linux 124
Working as Root 124
Using su 125
sudo 126
PolicyKit 126
Managing User Accounts 127
System Accounts and Normal Accounts 127
Creating Users 131
Modifying the Configuration Files 131
Using useradd 131
Home Directories 132
Managing User Properties 132
Configuration Files for User Management Defaults 132
Managing Password Properties 133
Creating a User Environment 134
Creating and Managing Group Accounts 135
Understanding Linux Groups 135
Creating Groups 136
Creating Groups with vigr 136
Using groupadd to Create Groups 137
Managing Group Properties 137
Summary 138
Exam Preparation Tasks 138
End-of-Chapter Lab 140
Chapter 7 Permissions Management 143
“Do I Know This Already?” Quiz 143
Foundation Topics 146
Managing File Ownership 146
Displaying Ownership 146
Changing User Ownership 147
Changing Group Ownership 148
Understanding Default Ownership 148
Managing Basic Permissions 149
Understanding Read, Write, and Execute Permissions 149
Applying Read, Write, and Execute Permissions 150
Managing Advanced Permissions 152
Understanding Advanced Permissions 152
Applying Advanced Permissions 155
Managing ACLs 156
Understanding ACLs 156
Preparing Your File System for ACLs 157
Changing and Viewing ACL Settings with setfacl and getfacl 157
Working with Default ACLs 159
Setting Default Permissions with umask 160
Working with User-Extended Attributes 162
Summary 163
Exam Preparation Tasks 163
End-of-Chapter Lab 165
Chapter 8 Configuring Networking 167
“Do I Know This Already?” Quiz 167
Foundation Topics 170
Networking Fundamentals 170
IP Addresses 170
IPv6 Addresses 171
Network Masks 171
Binary Notation 172
MAC Addresses 173
Protocol and Ports 173
Managing Network Addresses and Interfaces 174
Validating Network Configuration 175
Validating Network Address Configuration 175
Validating Routing 178
Validating the Availability of Ports and Services 178
Configuring Network Configuration with nmtui and nmcli 180
Required Permissions to Change Network Configuration 180
Configuring the Network with nmcli 181
Configuring the Network with nmtui 187
Working on Network Configuration Files 189
Setting Up Hostname and Name Resolution 190
Hostnames 190
DNS Name Resolution 192
Summary 194
Exam Preparation Tasks 194
End-of-Chapter Lab 195
Part II: Operating Running Systems
Chapter 9 Managing Software 197
“Do I Know This Already?” Quiz 197
Foundation Topics 200
Managing Software Packages with yum 200
Understanding the Role of Repositories 200
Registering Red Hat Enterprise Linux for Support 201
Managing Subscriptions 202
Specifying Which Repository to Use 203
Understanding Repository Security 206
Creating Your Own Repository 208
Using yum 209
Using yum to Find Software Packages 210
Getting More Information About Packages 211
Installing and Removing Software Packages 212
Showing Lists of Packages 214
Updating Packages 215
Working with yum Package Groups 216
Using yum History 218
Managing Package Module Streams 220
Understanding Modules 220
Managing Modules 221
Managing Software Packages with rpm 225
Understanding RPM Filenames 226
Querying the RPM Database 226
Querying RPM Package Files 227
Using repoquery 228
Summary 229
Exam Preparation Tasks 229
End-of-Chapter Labs 231
Chapter 10 Managing Processes 233
“Do I Know This Already?” Quiz 233
Foundation Topics 236
Introducing Process Management 236
Managing Shell Jobs 236
Running Jobs in the Foreground and Background 236
Managing Shell Jobs 237
Managing Parent-Child Relations 239
Using Common Command-Line Tools for Process Management 239
Understanding Processes and Threads 239
Using ps to Get Process Information 240
Adjusting Process Priority with nice 242
Sending Signals to Processes with kill, killall, and pkill 244
Using top to Manage Processes 246
Using tuned to Optimize Performance 248
Summary 249
Exam Preparation Tasks 249
End-of-Chapter Lab 251
Chapter 11 Working with Systemd 253
“Do I Know This Already?” Quiz 253
Foundation Topics 256
Understanding Systemd 256
Understanding Systemd Unit Locations 256
Understanding Systemd Service Units 257
Understanding Systemd Mount Units 258
Understanding Systemd Socket Units 259
Understanding Systemd Target Units 259
Managing Units Through Systemd 261
Managing Dependencies 263
Managing Unit Options 265
Summary 266
Exam Preparation Tasks 267
End-of-Chapter Lab 268
Chapter 12 Scheduling Tasks 271
“Do I Know This Already?” Quiz 271
Foundation Topics 274
Configuring cron to Automate Recurring Tasks 274
Managing the crond Service 274
Understanding cron Timing 276
Managing cron Configuration Files 276
Understanding the Purpose of anacron 278
Managing cron Security 280
Configuring at to Schedule Future Tasks 281
Summary 282
Exam Preparation Tasks 282
End-of-Chapter Lab 283
Chapter 13 Configuring Logging 285
“Do I Know This Already?” Quiz 285
Foundation Topics 288
Understanding System Logging 288
Understanding the Role of rsyslogd and journald 288
Reading Log Files 290
Understanding Log File Contents 290
Live Log File Monitoring 292
Using logger 292
Configuring rsyslogd 293
Understanding rsyslogd Configuration Files 293
Understanding rsyslog.conf Sections 293
Understanding Facilities, Priorities, and Log Destinations 294
Rotating Log Files 297
Working with journald 299
Using journalctl to Find Events 299
Preserving the Systemd Journal 302
Summary 304
Exam Preparation Tasks 304
End-of-Chapter Lab 306
Chapter 14 Managing Storage 309
“Do I Know This Already?” Quiz 309
Foundation Topics 312
Understanding MBR and GPT Partitions 312
Understanding the MBR Partitioning Scheme 312
Understanding the Need for GPT Partitioning 313
Understanding Storage Measurement Units 314
Managing Partitions and File Systems 314
Creating MBR Partitions with fdisk 315
Using Extended and Logical Partitions on MBR 319
Creating GPT Partitions with gdisk 320
Creating GPT Partitions with parted 324
Creating File Systems 325
Changing File System Properties 327
Managing Ext4 File System Properties 327
Managing XFS File System Properties 329
Adding Swap Partitions 329
Adding Swap Files 330
Mounting File Systems 330
Manually Mounting File Systems 331
Using Device Names, UUIDs, or Disk Labels 331
Automating File System Mounts Through /etc/fstab 332
Summary 335
Exam Preparation Tasks 335
End-of-Chapter Lab 337
Chapter 15 Managing Advanced Storage 339
“Do I Know This Already?” Quiz 339
Foundation Topics 342
Understanding LVM 342
LVM Architecture 342
LVM Features 343
Creating LVM Logical Volumes 344
Creating the Physical Volumes 346
Creating the Volume Groups 349
Creating the Logical Volumes and File Systems 351
Understanding LVM Device Naming 351
Resizing LVM Logical Volumes 353
Resizing Volume Groups 353
Resizing Logical Volumes and File Systems 354
Configuring Stratis 356
Understanding Stratis Architecture 356
Creating Stratis Storage 357
Managing Stratis 358
Configuring VDO 359
Understanding VDO 359
Setting Up VDO 360
Summary 362
Exam Preparation Tasks 362
End-of-Chapter Labs 364
Part III: Performing Advanced System Administration Tasks
Chapter 16 Basic Kernel Management 367
“Do I Know This Already?” Quiz 367
Foundation Topics 370
Understanding the Role of the Linux Kernel 370
Understanding the Use of Kernel Threads and Drivers 370
Analyzing What the Kernel Is Doing 371
Working with Kernel Modules 373
Understanding Hardware Initialization 374
Managing Kernel Modules 376
Checking Driver Availability for Hardware Devices 379
Managing Kernel Module Parameters 380
Upgrading the Linux Kernel 381
Summary 381
Exam Preparation Tasks 381
End-of-Chapter Lab 383
Chapter 17 Managing and Understanding the Boot Procedure 385
“Do I Know This Already?” Quiz 385
Foundation Topics 388
Managing Systemd Targets 388
Understanding Systemd Targets 388
Working with Targets 388
Understanding Target Units 389
Understanding Wants 390
Managing Systemd Targets 390
Isolating Targets 391
Setting the Default Target 393
Working with GRUB 2 394
Understanding GRUB 2 394
Understanding GRUB 2 Configuration Files 395
Modifying Default GRUB 2 Boot Options 395
Summary 396
Exam Preparation Tasks 397
End-of-Chapter Labs 398
Chapter 18 Essential Troubleshooting Skills 401
“Do I Know This Already?” Quiz 401
Foundation Topics 404
Understanding the RHEL 8 Boot Procedure 404
Passing Kernel Boot Arguments 406
Accessing the Boot Prompt 406
Starting a Troubleshooting Target 407
Using a Rescue Disk 408
Restoring System Access Using a Rescue Disk 409
Reinstalling GRUB Using a Rescue Disk 411
Re-creating the Initramfs Using a Rescue Disk 411
Fixing Common Issues 413
Reinstalling GRUB 2 413
Fixing the Initramfs 414
Recovering from File System Issues 414
Resetting the Root Password 416
Recovering Access to a Virtual Machine 416
Summary 418
Exam Preparation Tasks 418
End-of-Chapter Lab 420
Chapter 19 An Introduction to Bash Shell Scripting 423
“Do I Know This Already?” Quiz 423
Foundation Topics 426
Understanding Shell Scripting Core Elements 426
Using Variables and Input 428
Using Positional Parameters 428
Working with Variables 430
Using Conditional Loops 432
Working with if ... then ... else 432
Using || and && 433
Applying for 434
Understanding while and until 435
Understanding case 436
Bash Shell Script Debugging 438
Summary 438
Exam Preparation Tasks 438
End-of-Chapter Lab 440
Part IV: Managing Network Services
Chapter 20 Configuring SSH 443
“Do I Know This Already?” Quiz 443
Foundation Topics 446
Hardening the SSH Server 446
Limiting Root Access 446
Configuring Alternative Ports 447
Modifying SELinux to Allow for Port Changes 447
Limiting User Access 448
Using Other Useful sshd Options 449
Session Options 450
Connection Keepalive Options 450
Configuring Key-Based Authentication with Passphrases 451
Summary 452
Exam Preparation Tasks 452
End-of-Chapter Lab 454
Chapter 21 Managing Apache HTTP Services 457
“Do I Know This Already?” Quiz 457
Foundation Topics 460
Configuring a Basic Apache Server 460
Installing the Required Software 460
Identifying the Main Configuration File 460
Creating Web Server Content 463
Understanding Apache Configuration Files 464
Creating Apache Virtual Hosts 465
Summary 468
Exam Preparation Tasks 468
End-of-Chapter Lab 469
Chapter 22 Managing SELinux 471
“Do I Know This Already?” Quiz 472
Foundation Topics 475
Understanding SELinux Working and Modes 475
Understanding Context Settings and the Policy 479
Monitoring Current Context Labels 479
Setting Context Types 481
Finding the Context Type You Need 484
Restoring Default File Contexts 485
Using Boolean Settings to Modify SELinux Settings 487
Diagnosing and Addressing SELinux Policy Violations 488
Making SELinux Analyzing Easier 490
Preparing for SELinux Coverage on the Exam 492
Summary 492
Exam Preparation Tasks 492
End-of-Chapter Lab 494
Chapter 23 Configuring a Firewall 497
“Do I Know This Already?” Quiz 497
Foundation Topics 500
Understanding Linux Firewalling 500
Understanding Previous Solutions 500
Understanding Firewalld 500
Understanding Firewalld Zones 501
Understanding Firewalld Services 502
Working with Firewalld 503
Summary 506
Exam Preparation Tasks 506
End-of-Chapter Lab 508
Chapter 24 Accessing Network Storage 511
“Do I Know This Already?” Quiz 511
Foundation Topics 514
Using NFS Services 514
Understanding NFS Security 514
RHEL 8 NFS Versions 514
Setting Up NFS 515
Mounting the NFS Share 516
Using CIFS Services 516
Discovering CIFS Shares 517
Mounting Samba Shares 518
Authenticating to Samba Shares 518
Configuring a Samba Server 518
Mounting Remote File Systems Through fstab 520
Mounting NFS Shares Through fstab 520
Mounting Samba Shares Through fstab 521
Using Automount to Mount Remote File Systems 521
Understanding Automount 521
Defining Mounts in Automount 522
Configuring Automount for NFS 522
Using Wildcards in Automount 523
Summary 524
Exam Preparation Tasks 524
End-of-Chapter Lab 525
Chapter 25 Configuring Time Services 527
“Do I Know This Already?” Quiz 527
Foundation Topics 530
Understanding Local Time 530
Using Network Time Protocol 531
Managing Time on Red Hat Enterprise Linux 531
Using date 532
Using hwclock 532
Using timedatectl 533
Managing Time Zone Settings 535
Configuring Time Service Clients 537
Summary 538
Exam Preparation Tasks 539
End-of-Chapter Lab 540
Chapter 26 Managing Containers 543
Do I Know This Already Quiz 543
Foundation Topics 546
Understanding Containers 546
Container Host Requirements 546
Containers on RHEL 8 548
Container Orchestration 548
Running a Container 549
Working with Container Images 552
Using Registries 553
Finding Images 555
Inspecting Images 557
Performing Image Housekeeping 559
Managing Containers 560
Managing Container Status 560
Running Commands in a Container 561
Managing Container Ports 563
Managing Container Environment Variables 564
Managing Container Storage 565
Running Containers as Systemd Services 566
Exam Preparation Tasks 569
End-of-Chapter Lab 570
Chapter 27 Final Preparation 573
General Tips 573
Verifying Your Readiness 573
Registering for the Exam 573
On Exam Day 574
During the Exam 574
The Nondisclosure Agreement 576
Chapter 28 Theoretical Pre-Assessment Exam 577
Part V: RHCSA RHEL 8 Practice Exams
RHCSA Practice Exam A 581
RHCSA Practice Exam B 583
Appendix A Answers to the “Do I Know This Already?” Quizzes and Review Questions 585
Glossary 619
Online Elements:
RHCSA Practice Exam C
RHCSA Practice Exam D
Appendix B Memory Tables
Appendix C Memory Tables Answer Key
Appendix D Study Planner
Glossary