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