RHCSA Red Hat Enterprise Linux 8: training and exam preparation guide (ex200)

✍ Scribed by Asghar Ghori

• Tongue: English
• Leaves: 842
• Edition: 1
• Category: Library

✦ Table of Contents

Title Page
Copyright Page
Preface
Acknowledgments
About the Author
About this Book
Table of Contents
List of Figures
List of Tables
01. Local Installation
A Quick Look at Linux Development
Linux History in a Nutshell
Linux from Red Hat
Lab Infrastructure for Practice
What is Needed for the Lab?
The RHEL Installer Program
Where Do Installation Logs Go?
Virtual Console Screens
Exercise 1-1: Download and Install VirtualBox Software, and Create a Virtual Machine
Downloading and Installing VirtualBox
Creating a Virtual Machine
Exercise 1-2: Download and Install RHEL 8
Downloading RHEL 8 ISO Image
Attaching RHEL 8 ISO Image to the Virtual Machine
Launching the Installer
Adding Support for Keyboards and Languages
Configuring Time & Date
Choosing an Installation Source
Selecting Software to be Installed
Configuring Installation Destination
Configuring Network and Hostname
Beginning Installation
Setting root Password and Creating a User Account
Concluding Installation
Changing Default Boot Order
Performing Post-Installation Tasks
Logging In and Out
Logging In for the First Time
Logging Out
Chapter Summary
Check Your Understanding
Answers to Check Your Understanding
Do-It-Yourself Challenge Labs
Lab 1-1: Build RHEL8-VM2 (server2)
02. Initial Interaction with the System
Linux Graphical Environment
Display/Login Manager
Desktop Environment
Linux Directory Structure and File Systems
Top-Level Directories
File System Categories
The Root File System (/), Disk-Based
The Boot File System (/boot) – Disk-Based
The Home Directory (/home)
The Optional Directory (/opt)
The UNIX System Resources Directory (/usr)
The Variable Directory (/var)
The Temporary Directory (/tmp)
The Devices File System (/dev), Virtual
The Procfs File System (/proc), Virtual
The Runtime File System (/run), Virtual
The System File System (/sys), Virtual
Viewing Directory Hierarchy
Basic System Commands
Starting a GNOME Terminal Session
Understanding the Command Mechanics
Listing Files and Directories
Printing Working Directory
Navigating Directories
Identifying Terminal Device File
Inspecting System’s Uptime and Processor Load
Clearing the Screen
Determining Command Path
Viewing System Information
Viewing CPU Specs
Getting Help
Accessing Manual Pages
Headings in the Manual
Manual Sections
Searching by Keyword
Exposing Short Description
The info and pinfo Commands
Documentation in the /usr/share/doc Directory
Red Hat Enterprise Linux 8 Documentation
Chapter Summary
Check Your Understanding
Answers to Check Your Understanding
Do-It-Yourself Challenge Labs
Lab 2-1: Navigate Linux Directory Tree
Lab 2-2: Miscellaneous Tasks
Lab 2-3: Identify System and Kernel Information
Lab 2-4: Use Help
03. Basic File Management
Common File Types
Regular Files
Directory Files
Block and Character Special Device Files
Symbolic Links
Compression and Archiving
Using gzip and gunzip
Using bzip2 and bunzip2
Differences between gzip and bzip2
Using tar
Exercise 3-1: Create Compressed Archives
File Editing
Modes of Operation
Starting vim
Inserting text
Navigating within vim
Deleting Text
Undoing and Repeating
Searching for Text
Replacing Text
Copying, Moving, and Pasting Text
Changing Text
Saving and Quitting vim
File and Directory Operations
Creating Files and Directories
Displaying File Contents
Counting Words, Lines, and Characters in Text Files
Copying Files and Directories
Moving and Renaming Files and Directories
Removing Files and Directories
File Linking
Hard Link
Soft Link
Differences between Copying and Linking
Exercise 3-2: Create and Manage Hard Links
Exercise 3-3: Create and Manage Soft Links
Chapter Summary
Check Your Understanding
Answers to Check Your Understanding
Do-It-Yourself Challenge Labs
Lab 3-1: Archive, List, and Restore Files
Lab 3-2: Practice the vim Editor
Lab 3-3: File and Directory Operations
04. Advanced File Management
File and Directory Access Permissions
Determining Access Permissions
Permission Classes
Permission Types
Permission Modes
Modifying Access Permission Bits
Exercise 4-1: Modify Permission Bits Using Symbolic Form
Exercise 4-2: Modify Permission Bits Using Octal Form
Default Permissions
Calculating Default Permissions
Special File Permissions
The setuid Bit on Binary Executable Files
Exercise 4-3: Test the Effect of setuid Bit on Executable Files
The setgid Bit on Binary Executable Files
Exercise 4-4: Test the Effect of setgid Bit on Executable Files
The setgid Bit on Shared Directories
Exercise 4-5: Set up Shared Directory for Group Collaboration
The Sticky Bit on Public and Shared Writable Directories
Exercise 4-6: Test the Effect of Sticky Bit
File Searching
Using the find Command
Using find with -exec and -ok Flags
Using the locate Command
Access Control Lists (ACLs)
ACL Management Commands
The getfacl Command
The setfacl Command
The Role of the mask Value
Exercise 4-7: Identify, Apply, and Erase Access ACLs
Default ACLs
Exercise 4-8: Apply, Identify, and Erase Default ACLs
Chapter Summary
Check Your Understanding
Answers to Check Your Understanding
Do-It-Yourself Challenge Labs
Lab 4-1: Manipulate File Permissions
Lab 4-2: Configure Group Collaboration and Prevent File Deletion
Lab 4-3: Find Files
Lab 4-4: Find Files Using Different Criteria
Lab 4-5: Apply ACL Settings
05. Basic User Management
User Login Activity and Information
Listing Logged-In Users
Inspecting History of Successful Login Attempts and System Reboots
Viewing History of Failed User Login Attempts
Reporting Recent User Login Attempts
Examining User and Group Information
Local User Authentication Files
The passwd File
The shadow File
The group File
The gshadow File
The useradd and login.defs Configuration Files
User Account Management
The useradd, usermod, and userdel Commands
Exercise 5-1: Create a User Account with Default Attributes
Exercise 5-2: Create a User Account with Custom Values
Exercise 5-3: Modify and Delete a User Account
No-Login (Non-Interactive) User Account
Exercise 5-4: Create a User Account with No-Login Access
Chapter Summary
Check Your Understanding
Answers to Check Your Understanding
Do-It-Yourself Challenge Labs
Lab 5-1: Check User Login Attempts
Lab 5-2: Verify User and Group Identity
Lab 5-3: Create Users
Lab 5-4: Create User with Non-Interactive Shell
06. Advanced User Management
Password Aging and its Management
The chage Command
Exercise 6-1: Set and Confirm Password Aging with chage
The passwd Command
Exercise 6-2: Set and Confirm Password Aging with passwd
The usermod Command
Exercise 6-3: Lock and Unlock a User Account with usermod and passwd
Linux Groups and their Management
The groupadd, groupmod, and groupdel Commands
Exercise 6-4: Create a Group and Add Members
Exercise 6-5: Modify and Delete a Group Account
Substituting Users and Doing as Superuser
Substituting (or Switching) Users
Doing as Superuser (or Doing as Substitute User)
Owning User and Owning Group
Exercise 6-6: Modify File Owner and Owning Group
Chapter Summary
Check Your Understanding
Answers to Check Your Understanding
Do-It-Yourself Challenge Labs
Lab 6-1: Create User and Configure Password Aging
Lab 6-2: Lock and Unlock User
Lab 6-3: Modify Group
Lab 6-4: Configure sudo Access
Lab 6-5: Modify Owning User and Group
07. The Bash Shell
The Bourne-Again Shell
Internal and External Shell Commands
Shell and Environment Variables
Setting and Unsetting Variables
Command and Variable Substitutions
Exercise 7-1: Modify Primary Command Prompt
Input, Output, and Error Redirections
History Substitution
Editing at the Command Line
Tab Completion
Tilde Substitution
Alias Substitution
Metacharacters and Wildcard Characters
Piping Output of One Command as Input to Another
Quoting Mechanisms
Regular Expressions
Running and Controlling Jobs in Foreground and Background
Shell Startup Files
System-wide Shell Startup Files
Per-user Shell Startup Files
Chapter Summary
Check Your Understanding
Answers to Check Your Understanding
Do-It-Yourself Challenge Labs
Lab 7-1: Customize the Command Prompt
Lab 7-2: Redirect the Standard Input, Output, and Error
08. Linux Processes and Task Scheduling
Processes and Priorities
Process States
Viewing and Monitoring Processes with ps
Viewing and Monitoring Processes with top
Listing a Specific Process
Listing Processes by User and Group Ownership
Understanding Process Niceness
Viewing and Changing Process Niceness
Renicing a Running Process
Controlling Processes with Signals
Job Scheduling
Controlling User Access
Scheduler Log File
Using at
Exercise 8-1: Submit, View, List, and Remove an at Job
Using crontab
Syntax of User Crontables
Exercise 8-2: Add, List, and Remove a Cron Job
Anacron
Chapter Summary
Check Your Understanding
Answers to Check Your Understanding
Do-It-Yourself Challenge Labs
Lab 8-1: Nice and Renice a Process
Lab 8-2: Configure a User Crontab File
09. Basic Package Management
Package Overview
Packages and Packaging
Package Naming
Package Dependency
Package Database
Package Management Tools
Package Management with rpm
The rpm Command
Getting Ready to Use rpm
Querying Packages
Installing a Package
Upgrading a Package
Freshening a Package
Overwriting a Package
Removing a Package
Extracting Files from an Installable Package
Validating Package Integrity and Credibility
Viewing GPG Keys
Verifying Package Attributes
Exercise 9-1: Perform Package Management Tasks Using rpm
Chapter Summary
Check Your Understanding
Answers to Check Your Understanding
Do-It-Yourself Challenge Labs
Lab 9-1: Install and Verify Packages
Lab 9-2: Query and Remove Packages
10. Advanced Package Management
Advanced Package Management Concepts
Package Groups
Application Streams and Modules
BaseOS Repository
AppStream Repository
Benefits of Segregation
Module Streams
Module Profiles
dnf/yum Repository
Software Management with dnf
dnf Configuration File
The dnf Command
Exercise 10-1: Configure Access to Pre-Built ISO Repositories
Individual Package Management
Listing Available and Installed Packages
Installing and Updating Packages
Exhibiting Package Information
Removing Packages
Exercise 10-2: Manipulate Individual Packages
Determining Provider and Searching Package Metadata
Package Group Management
Listing Available and Installed Package Groups
Installing and Updating Package Groups
Removing Package Groups
Exercise 10-3: Manipulate Package Groups
Module Management
Listing Available and Installed Modules
Installing and Updating Modules
Displaying Module Information
Removing Modules
Exercise 10-4: Manipulate Modules
Switching Module Streams
Exercise 10-5: Install a Module from an Alternative Stream
Chapter Summary
Check Your Understanding
Answers to Check Your Understanding
Do-It-Yourself Challenge Labs
Lab 10-1: Configure Access to RHEL 8 Repositories
Lab 10-2: Install and Manage Individual Packages
Lab 10-3: Install and Manage Package Groups
Lab 10-4: Install and Manage Modules
Lab 10-5: Switch Module Streams and Install Software
11. Boot Process, GRUB2, and the Linux Kernel
Linux Boot Process
The Firmware Phase (BIOS and UEFI)
The Bootloader Phase
The Kernel Phase
The Initialization Phase
The GRUB2 Bootloader
Interacting with GRUB2
Understanding GRUB2 Configuration Files
Booting into Specific Targets
Exercise 11-1: Reset the root User Password
The Linux Kernel
Kernel Packages
Analyzing Kernel Version
Understanding Kernel Directory Structure
Installing the Kernel
Exercise 11-2: Download and Install a New Kernel
Chapter Summary
Check Your Understanding
Answers to Check Your Understanding
Do-It-Yourself Challenge Labs
Lab 11-1: Modify GRUB2 Timeout
Lab 11-2: Reset root User Password
Lab 11-3: Install New Kernel
12. System Initialization, Message Logging, and System Tuning
System Initialization and Service Management
Units
Targets
The systemctl Command
Listing and Viewing Units
Managing Service Units
Managing Target Units
System Logging
The Syslog Configuration File
Rotating Log Files
The Boot Log File
The System Log File
Logging Custom Messages
The systemd Journal
Retrieving and Viewing Messages
Preserving Journal Information
System Tuning
Tuning Profiles
The tuned-adm Command
Exercise 12-1: Manage Tuning Profiles
Chapter Summary
Check Your Understanding
Answers to Check Your Understanding
Do-It-Yourself Challenge Labs
Lab 12-1: Modify Default Boot Target
Lab 12-2: Record Custom Alerts
Lab 12-3: Apply Tuning Profile
13. Basic Storage Partitioning
Storage Management Overview
Master Boot Record (MBR)
GUID Partition Table (GPT)
Disk Partitions
Storage Management Tools
Thin Provisioning
Adding Storage for Practice
Exercise 13-1: Add Required Storage to server2
MBR Storage Management with parted
Exercise 13-2: Create an MBR Partition
Exercise 13-3: Delete an MBR Partition
GPT Storage Management with gdisk
Exercise 13-4: Create a GPT Partition
Exercise 13-5: Delete a GPT Partition
Storage Optimization with Virtual Data Optimizer (VDO)
How VDO Conserves Storage Space
Creating and Managing VDO Volumes
Exercise 13-6: Install Software and Activate VDO
Exercise 13-7: Create a VDO Volume
Exercise 13-8: Delete a VDO Volume
Chapter Summary
Check Your Understanding
Answers to Check Your Understanding
Do-It-Yourself Challenge Labs
Lab 13-1: Create and Remove Partitions with parted
Lab 13-2: Create and Remove Partitions with gdisk
Lab 13-3: Create and Delete VDO Volumes
Lab 13-4: Disable and Enable VDO Volume Features
14. Advanced Storage Partitioning
Logical Volume Manager (LVM)
Physical Volume
Volume Group
Physical Extent
Logical Volume
Logical Extent
LVM Operations and Commands
Exercise 14-1: Create a Physical Volume and Volume Group
Exercise 14-2: Create Logical Volumes
Exercise 14-3: Extend a Volume Group and a Logical Volume
Exercise 14-4: Rename, Reduce, Extend, and Remove Logical Volumes
Exercise 14-5: Reduce and Remove a Volume Group
Exercise 14-6: Uninitialize Physical Volumes
Stratis Volume-Managing File System
Stratis Management Operations and Command
Exercise 14-7: Install Software and Activate Stratis
Exercise 14-8: Create and Confirm a Pool and File System
Exercise 14-9: Expand and Rename a Pool and File System
Exercise 14-10: Destroy a File System and Pool
Chapter Summary
Check Your Understanding
Answers to Check Your Understanding
Do-It-Yourself Challenge Labs
Lab 14-1: Create Volume Group and Logical Volumes
Lab 14-2: Expand Volume Group and Logical Volume
Lab 14-3: Reduce and Remove Logical Volumes
Lab 14-4: Remove Volume Group and Physical Volumes
Lab 14-5: Create Stratis Pool
Lab 14-6: Expand and Destroy Stratis Pool
15. Local File Systems and Swap
File Systems and File System Types
Extended File Systems
XFS File System
VFAT File System
ISO9660 File System
File System Management
File System Administration Commands
Mounting and Unmounting File Systems
Determining the UUID of a File System
Labeling a File System
Automatically Mounting a File System at Reboots
Monitoring File System Usage
Calculating Disk Usage
Exercise 15-1: Create and Mount Ext4, VFAT, and XFS File Systems in Partitions
Exercise 15-2: Create and Mount XFS File System in VDO Volume
Exercise 15-3: Create and Mount Ext4 and XFS File Systems in LVM Logical Volumes
Exercise 15-4: Resize Ext4 and XFS File Systems in LVM Logical Volumes
Exercise 15-5: Create, Mount, and Expand XFS File System in Stratis Volume
Swap and its Management
Determining Current Swap Usage
Prioritizing Swap Spaces
Swap Administration Commands
Exercise 15-6: Create and Activate Swap in Partition and Logical Volume
Chapter Summary
Check Your Understanding
Answers to Check Your Understanding
Do-It-Yourself Challenge Labs
Lab 15-1: Create VFAT, Ext4, and XFS File Systems in Partitions and Mount Persistently
Lab 15-2: Create XFS File System in VDO Volume and Mount Persistently
Lab 15-3: Create Ext4 and XFS File Systems in LVM Logical Volumes and Mount Persistently
Lab 15-4: Extend Ext4 and XFS File Systems in LVM Logical Volumes
Lab 15-5: Create XFS File System in Stratis Volume and Mount Persistently
Lab 15-6: Create Swap in Partition and LVM Logical Volume and Activate Persistently
16. Remote File System
Network File System
Benefits of Using NFS
NFS Versions
NFS Server and Client Configuration
Exercise 16-1: Export Share on NFS Server
Exercise 16-2: Mount Share on NFS Client
Auto File System (AutoFS)
Benefits of Using AutoFS
How AutoFS Works
AutoFS Configuration File
AutoFS Maps
Exercise 16-3: Access NFS Share Using Direct Map
Exercise 16-4: Access NFS Share Using Indirect Map
Automounting User Home Directories
Exercise 16-5: Automount User Home Directories Using Indirect Map
Chapter Summary
Check Your Understanding
Answers to Check Your Understanding
Do-It-Yourself Challenge Labs
Lab 16-1: Configure NFS Share and Automount with Direct Map
Lab 16-2: Automount NFS Share with Indirect Map
17. Networking, Network Devices, and Network Connections
Networking Fundamentals
Hostname
Exercise 17-1: Change System Hostname
IPv4 Address
Network Classes
Subnetting
Subnet Mask
Classless Inter-Domain Routing (CIDR) Notation
Protocol
TCP and UDP Protocols
Well-Known Ports
ICMP Protocol
Ethernet Address
IPv6 Address
Major Differences between IPv4 and IPv6
Network Devices and Connections
Consistent Network Device Naming
Understanding Interface Connection Profile
Exercise 17-2: Add Network Devices to server10 and server20
Network Device and Connection Administration Tools
Exercise 17-3: Configure New Network Connection Manually
The NetworkManager Service
The nmcli Command
Exercise 17-4: Configure New Network Connection Using nmcli
Understanding Hosts Table
Testing Network Connectivity
Exercise 17-5: Update Hosts Table and Test Connectivity
Chapter Summary
Check Your Understanding
Answers to Check Your Understanding
Do-It-Yourself Challenge Labs
Lab 17-1: Add New Interface and Configure Connection Profile with nmcli
Lab 17-2: Add New Interface and Configure Connection Profile Manually
18. Time Synchronization and Hostname Resolution
Time Synchronization
Time Sources
NTP Roles
Stratum Levels
Chrony Configuration File
Chrony Daemon and Command
Exercise 18-1: Configure NTP Client
Displaying and Setting System Date and Time
DNS and Name Resolution
DNS Name Space and Domains
DNS Roles
Understanding Resolver Configuration File
Performing Name Resolution with dig
Performing Name Resolution with host
Performing Name Resolution with nslookup
Performing Name Resolution with getent
Chapter Summary
Check Your Understanding
Answers to Check Your Understanding
Do-It-Yourself Challenge Labs
Lab 18-1: Modify System Date and Time
Lab 18-2: Configure Chrony
19. The Secure Shell Service
The OpenSSH Service
Common Encryption Techniques
Authentication Methods
OpenSSH Protocol Version and Algorithms
OpenSSH Packages
OpenSSH Server Daemon and Client Commands
Server Configuration File
Client Configuration File
System Access and File Transfer
Exercise 19-1: Access RHEL System from Another RHEL System
Exercise 19-2: Access RHEL System from Windows
Exercise 19-3: Generate, Distribute, and Use SSH Keys
Executing Commands Remotely Using ssh
Copying Files Remotely Using scp
Transferring Files Remotely Using sftp
Synchronizing Files Remotely Using rsync
Chapter Summary
Check Your Understanding
Answers to Check Your Understanding
Do-It-Yourself Challenge Labs
Lab 19-1: Establish Key-Based Authentication
Lab 19-2: Test the Effect of PermitRootLogin Directive
20.The Linux Firewall
Firewall Overview
Overview of firewalld
firewalld Zones
Zone Configuration Files
firewalld Services
Service Configuration Files
Firewall Management
The firewall-cmd Command
Querying the Operational Status of firewalld
Exercise 20-1: Add Services and Ports, and Manage Zones
Exercise 20-2: Remove Services and Ports, and Manage Zones
Exercise 20-3: Test the Effect of Firewall Rule
Chapter Summary
Check Your Understanding
Answers to Check Your Understanding
Do-It-Yourself Challenge Labs
Lab 20-1: Add Service to Firewall
Lab 20-2: Add Port Range to Firewall
21.Security Enhanced Linux
Security Enhanced Linux
Terminology
SELinux Contexts for Users
SELinux Contexts for Processes
SELinux Contexts for Files
Copying, Moving, and Archiving Files with SELinux Contexts
SELinux Contexts for Ports
Domain Transitioning
SELinux Booleans
SELinux Administration
Management Commands
Viewing and Controlling SELinux Operational State
Querying Status
Exercise 21-1: Modify SELinux File Context
Exercise 21-2: Add and Apply File Context
Exercise 21-3: Add and Delete Network Ports
Exercise 21-4: Copy Files with and without Context
Exercise 21-5: View and Toggle SELinux Boolean Values
Monitoring and Analyzing SELinux Violations
Chapter Summary
Check Your Understanding
Answers to Check Your Understanding
Do-It-Yourself Challenge Labs
Lab 21-1: Disable and Enable the SELinux Operating Mode
Lab 21-2: Modify Context on Files
Lab 21-3: Add Network Port to Policy Database
Lab 21-4: Copy Files with and without Context
Lab 21-5: Flip SELinux Booleans
Appendix A: Sample RHCSA Exam 1
Appendix B: Sample RHCSA Exam 2
Appendix C: Sample RHCSA Exam 3
Appendix D: Sample RHCSA Exam 4
Bibliography
Glossary
Index