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