RHCSA Red Hat Enterprise Linux 8: Training and Exam Preparation Guide (EX200)

Title Page......Page 2
Copyright Page......Page 3
Preface......Page 5
Acknowledgments......Page 8
About the Author......Page 9
About this Book......Page 17
Table of Contents......Page 19
List of Figures......Page 42
List of Tables......Page 44
01. Local Installation......Page 46
A Quick Look at Linux Development......Page 47
Linux History in a Nutshell......Page 48
Lab Infrastructure for Practice......Page 49
What is Needed for the Lab?......Page 50
Where Do Installation Logs Go?......Page 52
Virtual Console Screens......Page 53
Downloading and Installing VirtualBox......Page 54
Creating a Virtual Machine......Page 62
Exercise 1-2: Download and Install RHEL 8......Page 68
Downloading RHEL 8 ISO Image......Page 69
Attaching RHEL 8 ISO Image to the Virtual Machine......Page 72
Launching the Installer......Page 73
Adding Support for Keyboards and Languages......Page 75
Choosing an Installation Source......Page 76
Selecting Software to be Installed......Page 77
Configuring Installation Destination......Page 79
Configuring Network and Hostname......Page 80
Beginning Installation......Page 83
Setting root Password and Creating a User Account......Page 84
Concluding Installation......Page 86
Changing Default Boot Order......Page 87
Performing Post-Installation Tasks......Page 88
Logging In for the First Time......Page 90
Logging Out......Page 93
Chapter Summary......Page 94
Answers to Check Your Understanding......Page 95
Lab 1-1: Build RHEL8-VM2 (server2)......Page 96
02. Initial Interaction with the System......Page 97
Linux Graphical Environment......Page 98
Display/Login Manager......Page 99
Desktop Environment......Page 100
Linux Directory Structure and File Systems......Page 102
Top-Level Directories......Page 103
File System Categories......Page 104
The Home Directory (/home)......Page 105
The UNIX System Resources Directory (/usr)......Page 106
The Variable Directory (/var)......Page 107
The Procfs File System (/proc), Virtual......Page 108
Viewing Directory Hierarchy......Page 109
Starting a GNOME Terminal Session......Page 111
Understanding the Command Mechanics......Page 112
Listing Files and Directories......Page 114
Navigating Directories......Page 117
Identifying Terminal Device File......Page 119
Determining Command Path......Page 120
Viewing System Information......Page 121
Viewing CPU Specs......Page 122
Accessing Manual Pages......Page 123
Headings in the Manual......Page 124
Manual Sections......Page 125
Searching by Keyword......Page 126
The info and pinfo Commands......Page 128
Documentation in the /usr/share/doc Directory......Page 129
Chapter Summary......Page 130
Check Your Understanding......Page 131
Answers to Check Your Understanding......Page 132
Lab 2-2: Miscellaneous Tasks......Page 133
Lab 2-4: Use Help......Page 134
03. Basic File Management......Page 135
Common File Types......Page 137
Regular Files......Page 138
Block and Character Special Device Files......Page 139
Compression and Archiving......Page 141
Using gzip and gunzip......Page 142
Differences between gzip and bzip2......Page 143
Using tar......Page 144
Exercise 3-1: Create Compressed Archives......Page 146
Modes of Operation......Page 148
Inserting text......Page 149
Navigating within vim......Page 150
Undoing and Repeating......Page 151
Searching for Text......Page 152
Copying, Moving, and Pasting Text......Page 153
Changing Text......Page 154
Saving and Quitting vim......Page 155
Creating Files and Directories......Page 156
Displaying File Contents......Page 159
Counting Words, Lines, and Characters in Text Files......Page 162
Copying Files and Directories......Page 163
Moving and Renaming Files and Directories......Page 165
Removing Files and Directories......Page 166
File Linking......Page 168
Hard Link......Page 169
Soft Link......Page 170
Differences between Copying and Linking......Page 172
Exercise 3-2: Create and Manage Hard Links......Page 173
Exercise 3-3: Create and Manage Soft Links......Page 175
Chapter Summary......Page 176
Check Your Understanding......Page 177
Answers to Check Your Understanding......Page 178
Do-It-Yourself Challenge Labs......Page 179
Lab 3-3: File and Directory Operations......Page 180
04. Advanced File Management......Page 181
File and Directory Access Permissions......Page 183
Permission Types......Page 184
Modifying Access Permission Bits......Page 185
Exercise 4-1: Modify Permission Bits Using Symbolic Form......Page 186
Default Permissions......Page 188
Calculating Default Permissions......Page 189
The setuid Bit on Binary Executable Files......Page 191
Exercise 4-3: Test the Effect of setuid Bit on Executable Files......Page 192
The setgid Bit on Binary Executable Files......Page 193
Exercise 4-4: Test the Effect of setgid Bit on Executable Files......Page 194
The setgid Bit on Shared Directories......Page 195
Exercise 4-5: Set up Shared Directory for Group Collaboration......Page 196
The Sticky Bit on Public and Shared Writable Directories......Page 197
Exercise 4-6: Test the Effect of Sticky Bit......Page 198
Using the find Command......Page 200
Using the locate Command......Page 203
Access Control Lists (ACLs)......Page 204
The getfacl Command......Page 205
The setfacl Command......Page 206
The Role of the mask Value......Page 207
Exercise 4-7: Identify, Apply, and Erase Access ACLs......Page 208
Default ACLs......Page 210
Exercise 4-8: Apply, Identify, and Erase Default ACLs......Page 211
Check Your Understanding......Page 214
Answers to Check Your Understanding......Page 215
Lab 4-1: Manipulate File Permissions......Page 216
Lab 4-5: Apply ACL Settings......Page 217
05. Basic User Management......Page 218
User Login Activity and Information......Page 220
Listing Logged-In Users......Page 221
Inspecting History of Successful Login Attempts and System Reboots......Page 222
Viewing History of Failed User Login Attempts......Page 224
Reporting Recent User Login Attempts......Page 225
Examining User and Group Information......Page 226
Local User Authentication Files......Page 227
The passwd File......Page 228
The shadow File......Page 230
The group File......Page 233
The gshadow File......Page 235
The useradd and login.defs Configuration Files......Page 237
The useradd, usermod, and userdel Commands......Page 239
Exercise 5-1: Create a User Account with Default Attributes......Page 241
Exercise 5-2: Create a User Account with Custom Values......Page 242
Exercise 5-3: Modify and Delete a User Account......Page 243
No-Login (Non-Interactive) User Account......Page 244
Chapter Summary......Page 245
Check Your Understanding......Page 246
Answers to Check Your Understanding......Page 247
Lab 5-2: Verify User and Group Identity......Page 248
Lab 5-4: Create User with Non-Interactive Shell......Page 249
06. Advanced User Management......Page 250
The chage Command......Page 253
Exercise 6-1: Set and Confirm Password Aging with chage......Page 254
Exercise 6-2: Set and Confirm Password Aging with passwd......Page 256
Exercise 6-3: Lock and Unlock a User Account with usermod and passwd......Page 258
Linux Groups and their Management......Page 259
The groupadd, groupmod, and groupdel Commands......Page 260
Exercise 6-4: Create a Group and Add Members......Page 261
Exercise 6-5: Modify and Delete a Group Account......Page 262
Substituting (or Switching) Users......Page 263
Doing as Superuser (or Doing as Substitute User)......Page 265
Owning User and Owning Group......Page 268
Exercise 6-6: Modify File Owner and Owning Group......Page 269
Chapter Summary......Page 270
Check Your Understanding......Page 271
Answers to Check Your Understanding......Page 272
Lab 6-2: Lock and Unlock User......Page 273
Lab 6-5: Modify Owning User and Group......Page 274
07. The Bash Shell......Page 275
The Bourne-Again Shell......Page 277
Internal and External Shell Commands......Page 278
Shell and Environment Variables......Page 279
Setting and Unsetting Variables......Page 280
Command and Variable Substitutions......Page 282
Exercise 7-1: Modify Primary Command Prompt......Page 283
Input, Output, and Error Redirections......Page 284
History Substitution......Page 286
Editing at the Command Line......Page 288
Tab Completion......Page 289
Tilde Substitution......Page 290
Alias Substitution......Page 292
Metacharacters and Wildcard Characters......Page 294
Piping Output of One Command as Input to Another......Page 297
Quoting Mechanisms......Page 298
Regular Expressions......Page 300
Running and Controlling Jobs in Foreground and Background......Page 303
System-wide Shell Startup Files......Page 306
Per-user Shell Startup Files......Page 308
Check Your Understanding......Page 310
Answers to Check Your Understanding......Page 311
Do-It-Yourself Challenge Labs......Page 312
Lab 7-2: Redirect the Standard Input, Output, and Error......Page 313
08. Linux Processes and Task Scheduling......Page 314
Processes and Priorities......Page 316
Process States......Page 317
Viewing and Monitoring Processes with ps......Page 318
Viewing and Monitoring Processes with top......Page 321
Listing a Specific Process......Page 323
Understanding Process Niceness......Page 324
Viewing and Changing Process Niceness......Page 325
Controlling Processes with Signals......Page 327
Job Scheduling......Page 330
Controlling User Access......Page 331
Scheduler Log File......Page 332
Using at......Page 333
Exercise 8-1: Submit, View, List, and Remove an at Job......Page 334
Using crontab......Page 335
Syntax of User Crontables......Page 336
Exercise 8-2: Add, List, and Remove a Cron Job......Page 338
Anacron......Page 339
Chapter Summary......Page 341
Check Your Understanding......Page 342
Answers to Check Your Understanding......Page 343
Lab 8-2: Configure a User Crontab File......Page 344
09. Basic Package Management......Page 345
Package Overview......Page 347
Packages and Packaging......Page 348
Package Dependency......Page 349
Package Management Tools......Page 350
The rpm Command......Page 351
Getting Ready to Use rpm......Page 353
Querying Packages......Page 355
Installing a Package......Page 357
Freshening a Package......Page 358
Removing a Package......Page 359
Validating Package Integrity and Credibility......Page 360
Viewing GPG Keys......Page 362
Verifying Package Attributes......Page 363
Exercise 9-1: Perform Package Management Tasks Using rpm......Page 366
Check Your Understanding......Page 368
Answers to Check Your Understanding......Page 369
Lab 9-2: Query and Remove Packages......Page 370
10. Advanced Package Management......Page 371
Package Groups......Page 373
BaseOS Repository......Page 374
Module Streams......Page 375
dnf/yum Repository......Page 376
dnf Configuration File......Page 378
The dnf Command......Page 381
Exercise 10-1: Configure Access to Pre-Built ISO Repositories......Page 383
Listing Available and Installed Packages......Page 385
Installing and Updating Packages......Page 388
Exhibiting Package Information......Page 389
Removing Packages......Page 390
Exercise 10-2: Manipulate Individual Packages......Page 391
Determining Provider and Searching Package Metadata......Page 394
Listing Available and Installed Package Groups......Page 396
Installing and Updating Package Groups......Page 398
Removing Package Groups......Page 400
Exercise 10-3: Manipulate Package Groups......Page 401
Listing Available and Installed Modules......Page 405
Installing and Updating Modules......Page 407
Displaying Module Information......Page 408
Removing Modules......Page 409
Exercise 10-4: Manipulate Modules......Page 410
Switching Module Streams......Page 413
Exercise 10-5: Install a Module from an Alternative Stream......Page 414
Check Your Understanding......Page 418
Answers to Check Your Understanding......Page 419
Lab 10-1: Configure Access to RHEL 8 Repositories......Page 420
Lab 10-4: Install and Manage Modules......Page 421
Lab 10-5: Switch Module Streams and Install Software......Page 422
11. Boot Process, GRUB2, and the Linux Kernel......Page 423
The Firmware Phase (BIOS and UEFI)......Page 424
The Initialization Phase......Page 426
The GRUB2 Bootloader......Page 427
Interacting with GRUB2......Page 428
Understanding GRUB2 Configuration Files......Page 430
Booting into Specific Targets......Page 433
Exercise 11-1: Reset the root User Password......Page 434
The Linux Kernel......Page 435
Kernel Packages......Page 436
Analyzing Kernel Version......Page 437
Understanding Kernel Directory Structure......Page 438
Installing the Kernel......Page 443
Exercise 11-2: Download and Install a New Kernel......Page 444
Chapter Summary......Page 448
Check Your Understanding......Page 449
Lab 11-1: Modify GRUB2 Timeout......Page 450
Lab 11-3: Install New Kernel......Page 451
12. System Initialization, Message Logging, and System Tuning......Page 452
System Initialization and Service Management......Page 455
Units......Page 457
Targets......Page 460
The systemctl Command......Page 462
Listing and Viewing Units......Page 464
Managing Service Units......Page 466
Managing Target Units......Page 469
System Logging......Page 473
The Syslog Configuration File......Page 474
Rotating Log Files......Page 476
The Boot Log File......Page 479
The System Log File......Page 480
Logging Custom Messages......Page 481
Retrieving and Viewing Messages......Page 482
Preserving Journal Information......Page 485
System Tuning......Page 487
Tuning Profiles......Page 488
Exercise 12-1: Manage Tuning Profiles......Page 490
Chapter Summary......Page 492
Check Your Understanding......Page 493
Answers to Check Your Understanding......Page 494
Lab 12-1: Modify Default Boot Target......Page 495
Lab 12-3: Apply Tuning Profile......Page 496
13. Basic Storage Partitioning......Page 497
Storage Management Overview......Page 498
Master Boot Record (MBR)......Page 499
Disk Partitions......Page 500
Thin Provisioning......Page 502
Exercise 13-1: Add Required Storage to server2......Page 503
MBR Storage Management with parted......Page 507
Exercise 13-2: Create an MBR Partition......Page 508
Exercise 13-3: Delete an MBR Partition......Page 509
GPT Storage Management with gdisk......Page 510
Exercise 13-4: Create a GPT Partition......Page 511
Storage Optimization with Virtual Data Optimizer (VDO)......Page 514
Creating and Managing VDO Volumes......Page 515
Exercise 13-6: Install Software and Activate VDO......Page 516
Exercise 13-7: Create a VDO Volume......Page 517
Exercise 13-8: Delete a VDO Volume......Page 519
Chapter Summary......Page 520
Check Your Understanding......Page 521
Answers to Check Your Understanding......Page 522
Lab 13-1: Create and Remove Partitions with parted......Page 523
Lab 13-4: Disable and Enable VDO Volume Features......Page 524
14. Advanced Storage Partitioning......Page 525
Logical Volume Manager (LVM)......Page 527
Physical Volume......Page 528
Volume Group......Page 529
Logical Volume......Page 530
Logical Extent......Page 531
LVM Operations and Commands......Page 532
Exercise 14-1: Create a Physical Volume and Volume Group......Page 534
Exercise 14-2: Create Logical Volumes......Page 537
Exercise 14-3: Extend a Volume Group and a Logical Volume......Page 539
Exercise 14-4: Rename, Reduce, Extend, and Remove Logical Volumes......Page 541
Exercise 14-5: Reduce and Remove a Volume Group......Page 543
Exercise 14-6: Uninitialize Physical Volumes......Page 544
Stratis Volume-Managing File System......Page 545
Stratis Management Operations and Command......Page 547
Exercise 14-7: Install Software and Activate Stratis......Page 548
Exercise 14-8: Create and Confirm a Pool and File System......Page 549
Exercise 14-9: Expand and Rename a Pool and File System......Page 551
Exercise 14-10: Destroy a File System and Pool......Page 552
Chapter Summary......Page 553
Check Your Understanding......Page 554
Answers to Check Your Understanding......Page 556
Lab 14-2: Expand Volume Group and Logical Volume......Page 557
Lab 14-6: Expand and Destroy Stratis Pool......Page 558
15. Local File Systems and Swap......Page 559
File Systems and File System Types......Page 561
Extended File Systems......Page 565
XFS File System......Page 566
VFAT File System......Page 567
File System Management......Page 568
File System Administration Commands......Page 569
Mounting and Unmounting File Systems......Page 570
Determining the UUID of a File System......Page 572
Labeling a File System......Page 574
Automatically Mounting a File System at Reboots......Page 575
Monitoring File System Usage......Page 577
Calculating Disk Usage......Page 578
Exercise 15-1: Create and Mount Ext4, VFAT, and XFS File Systems in Partitions......Page 579
Exercise 15-2: Create and Mount XFS File System in VDO Volume......Page 581
Exercise 15-3: Create and Mount Ext4 and XFS File Systems in LVM Logical Volumes......Page 584
Exercise 15-4: Resize Ext4 and XFS File Systems in LVM Logical Volumes......Page 587
Exercise 15-5: Create, Mount, and Expand XFS File System in Stratis Volume......Page 590
Swap and its Management......Page 592
Determining Current Swap Usage......Page 594
Prioritizing Swap Spaces......Page 595
Exercise 15-6: Create and Activate Swap in Partition and Logical Volume......Page 596
Check Your Understanding......Page 599
Answers to Check Your Understanding......Page 601
Lab 15-1: Create VFAT, Ext4, and XFS File Systems in Partitions and Mount Persistently......Page 603
Lab 15-4: Extend Ext4 and XFS File Systems in LVM Logical Volumes......Page 604
Lab 15-6: Create Swap in Partition and LVM Logical Volume and Activate Persistently......Page 605
16. Remote File System......Page 606
Network File System......Page 608
Benefits of Using NFS......Page 609
NFS Server and Client Configuration......Page 610
Exercise 16-1: Export Share on NFS Server......Page 611
Exercise 16-2: Mount Share on NFS Client......Page 613
Benefits of Using AutoFS......Page 615
AutoFS Configuration File......Page 616
AutoFS Maps......Page 617
Exercise 16-3: Access NFS Share Using Direct Map......Page 619
Exercise 16-4: Access NFS Share Using Indirect Map......Page 622
Exercise 16-5: Automount User Home Directories Using Indirect Map......Page 624
Chapter Summary......Page 627
Check Your Understanding......Page 628
Answers to Check Your Understanding......Page 629
Lab 16-2: Automount NFS Share with Indirect Map......Page 630
17. Networking, Network Devices, and Network Connections......Page 631
Networking Fundamentals......Page 633
Hostname......Page 634
Exercise 17-1: Change System Hostname......Page 635
IPv4 Address......Page 636
Network Classes......Page 637
Subnetting......Page 639
Subnet Mask......Page 640
Protocol......Page 641
TCP and UDP Protocols......Page 642
ICMP Protocol......Page 643
Ethernet Address......Page 644
IPv6 Address......Page 645
Major Differences between IPv4 and IPv6......Page 646
Consistent Network Device Naming......Page 647
Understanding Interface Connection Profile......Page 648
Exercise 17-2: Add Network Devices to server10 and server20......Page 651
Exercise 17-3: Configure New Network Connection Manually......Page 653
The nmcli Command......Page 655
Exercise 17-4: Configure New Network Connection Using nmcli......Page 657
Understanding Hosts Table......Page 660
Testing Network Connectivity......Page 661
Exercise 17-5: Update Hosts Table and Test Connectivity......Page 662
Chapter Summary......Page 664
Check Your Understanding......Page 665
Answers to Check Your Understanding......Page 666
Lab 17-1: Add New Interface and Configure Connection Profile with nmcli......Page 667
Lab 17-2: Add New Interface and Configure Connection Profile Manually......Page 668
18. Time Synchronization and Hostname Resolution......Page 669
Time Synchronization......Page 671
Time Sources......Page 672
NTP Roles......Page 673
Stratum Levels......Page 674
Chrony Configuration File......Page 675
Chrony Daemon and Command......Page 677
Exercise 18-1: Configure NTP Client......Page 678
Displaying and Setting System Date and Time......Page 681
DNS and Name Resolution......Page 682
DNS Name Space and Domains......Page 683
Understanding Resolver Configuration File......Page 684
Performing Name Resolution with dig......Page 687
Performing Name Resolution with host......Page 688
Performing Name Resolution with getent......Page 689
Chapter Summary......Page 690
Check Your Understanding......Page 691
Answers to Check Your Understanding......Page 692
Lab 18-2: Configure Chrony......Page 693
19. The Secure Shell Service......Page 694
The OpenSSH Service......Page 696
Authentication Methods......Page 697
OpenSSH Protocol Version and Algorithms......Page 699
OpenSSH Server Daemon and Client Commands......Page 700
Server Configuration File......Page 701
Client Configuration File......Page 704
Exercise 19-1: Access RHEL System from Another RHEL System......Page 706
Exercise 19-2: Access RHEL System from Windows......Page 708
Exercise 19-3: Generate, Distribute, and Use SSH Keys......Page 710
Executing Commands Remotely Using ssh......Page 712
Copying Files Remotely Using scp......Page 713
Transferring Files Remotely Using sftp......Page 715
Synchronizing Files Remotely Using rsync......Page 717
Chapter Summary......Page 718
Check Your Understanding......Page 719
Answers to Check Your Understanding......Page 720
Lab 19-1: Establish Key-Based Authentication......Page 721
Lab 19-2: Test the Effect of PermitRootLogin Directive......Page 722
20.The Linux Firewall......Page 723
Firewall Overview......Page 725
firewalld Zones......Page 726
Zone Configuration Files......Page 728
firewalld Services......Page 729
Service Configuration Files......Page 730
The firewall-cmd Command......Page 731
Querying the Operational Status of firewalld......Page 733
Exercise 20-1: Add Services and Ports, and Manage Zones......Page 734
Exercise 20-2: Remove Services and Ports, and Manage Zones......Page 736
Exercise 20-3: Test the Effect of Firewall Rule......Page 738
Check Your Understanding......Page 739
Answers to Check Your Understanding......Page 740
Lab 20-2: Add Port Range to Firewall......Page 741
21.Security Enhanced Linux......Page 742
Security Enhanced Linux......Page 744
Terminology......Page 745
SELinux Contexts for Users......Page 749
SELinux Contexts for Processes......Page 750
Copying, Moving, and Archiving Files with SELinux Contexts......Page 751
Domain Transitioning......Page 752
SELinux Booleans......Page 754
Management Commands......Page 755
Viewing and Controlling SELinux Operational State......Page 756
Querying Status......Page 758
Exercise 21-1: Modify SELinux File Context......Page 760
Exercise 21-2: Add and Apply File Context......Page 761
Exercise 21-3: Add and Delete Network Ports......Page 762
Exercise 21-4: Copy Files with and without Context......Page 763
Exercise 21-5: View and Toggle SELinux Boolean Values......Page 764
Monitoring and Analyzing SELinux Violations......Page 766
Chapter Summary......Page 768
Check Your Understanding......Page 769
Answers to Check Your Understanding......Page 770
Lab 21-2: Modify Context on Files......Page 771
Lab 21-5: Flip SELinux Booleans......Page 772
Appendix A: Sample RHCSA Exam 1......Page 773
Appendix B: Sample RHCSA Exam 2......Page 778
Appendix C: Sample RHCSA Exam 3......Page 783
Appendix D: Sample RHCSA Exam 4......Page 788
Bibliography......Page 793
Glossary......Page 795
Index......Page 819