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 xxiv



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



Understanding Access to Repositories 8



Setup Requirements 9



Cert Guide Environment Description 9



Performing a Manual Installation 10



Summary 24



Exam Preparation Tasks 25



Review Questions 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



Review Questions 51



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 65



Moving Files 66



Deleting Files 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



Using Compression 74



Summary 75



Exam Preparation Tasks 75



Review Questions 77



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



Review Questions 96



End-of-Chapter Lab 96



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



Configuring Key-Based Authentication for SSH 114



Using Passphrases or Not? 114



Using the screen Command 115



Summary 117



Exam Preparation Tasks 117



Review Questions 118



End-of-Chapter Labs 118



Chapter 6 User and Group Management 121



"Do I Know This Already?" Quiz 121



Foundation Topics 124



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



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



Managing Group Properties 137



Summary 138



Exam Preparation Tasks 138



Review Questions 140



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



Review Questions 164



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



Review Questions 195



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



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



Review Questions 230



End-of-Chapter Labs 231



Chapter 10 Managing Processes 233



"Do I Know This Already?" Quiz 233



Foundation Topics 236



Introduction to 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



Review Questions 250



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



Review Questions 268



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



Review Questions 283



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



Review Questions 305



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



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



Review Questions 336



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



Review Questions 363



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



Review Questions 382



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



Understanding Target Units 389



Understanding Wants 390



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



Review Questions 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



Review Questions 419



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



Review Questions 439



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



Review Questions 453



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



Review Questions 469



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



Review Questions 494



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



Review Questions 507



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



Mounting the NFS Share 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



Review Questions 525



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 535fa



Configuring Time Service Clients 537



Summary 538



Exam Preparation Tasks 539



Review Questions 540



End-of-Chapter Lab 540



Chapter 26 Final Preparation 541



General Tips 541



Verifying Your Readiness 541



Registering for the Exam 541



On Exam Day 542



Chapter 27 Theoretical Pre-Assessment Exam 545



Part V: RHCSA RHEL 8 Practice Exams



RHCSA Practice Exam A 549



RHCSA Practice Exam B 551



Appendix A Answers to the "Do I Know This Already?" Quizzes and Review Questions 553



Glossary 587







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











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