01 - System Installation & Initial Configuration¶

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1. Executive Summary¶

Topic Scope: RHEL 9 installation process, initial system configuration, and post-installation setup

RHCSA Relevance: Foundation knowledge - while not directly tested, understanding installation helps with system administration tasks

Exam Weight: Medium - Installation concepts appear in troubleshooting and system configuration scenarios

Prerequisites: Basic understanding of Linux concepts and virtualization

Related Topics: Boot Process & GRUB, Storage & LVM, Network Configuration

2. Conceptual Foundation¶

Core Theory¶

RHEL installation involves deploying the Red Hat Enterprise Linux operating system using the Anaconda installer. The process includes:

System preparation: Hardware verification and boot media creation
Installation configuration: Language, storage, network, and user setup
Package selection: Choosing software packages based on intended use
Post-installation: Initial login and system verification

Real-World Applications¶

Data center deployments: Automated installation using Kickstart files
Development environments: Virtual machine installations for testing
Production servers: Careful configuration for specific workloads
Lab environments: Practice installations for certification preparation

Common Misconceptions¶

Installation = configuration: Installation only provides the base system
Default settings are optimal: Production systems require careful customization
GUI required: RHEL can be fully managed from command line
Single partition layout: Multiple partitions provide better organization and security

Key Terminology¶

Anaconda: The RHEL installer program
ISO image: Bootable installation media file
Kickstart: Automated installation configuration file
Base environment: Predefined software package collections
Root filesystem: Primary filesystem containing the operating system
Boot partition: Separate partition containing boot loader and kernel files

3. Command Mastery¶

Pre-Installation Commands¶

# Verify system requirements
lscpu                    # Check CPU information
free -h                  # Check memory availability
lsblk                    # List available storage devices
ip addr show             # Check network interfaces

# ISO verification (if needed)
sha256sum rhel-9.1-x86_64-dvd.iso

Post-Installation Verification¶

# System information
hostnamectl              # Display system hostname and info
uname -a                 # Kernel and system information
cat /etc/os-release      # Operating system version details

# Storage verification
lsblk                    # List all block devices
df -h                    # Check filesystem usage
mount | column -t        # Display mounted filesystems

# Network verification
ip addr show             # Display IP configuration
ping -c 3 8.8.8.8       # Test network connectivity

Initial System Configuration¶

# Set system hostname
hostnamectl set-hostname server1.example.com

# Configure timezone
timedatectl set-timezone America/New_York
timedatectl status

# Update system (post-installation)
dnf update -y

# Check enabled services
systemctl list-unit-files --type=service --state=enabled

4. Installation Workflows¶

Standard Installation Procedure¶

Boot from Installation Media
Select "Install Red Hat Enterprise Linux 9.x"
Wait for Anaconda to load (may take several minutes)
Language and Localization
Select installation language
Configure keyboard layout
Set date and time/timezone
Installation Source
Verify installation media is detected
Configure additional repositories if needed
Software Selection Available Base Environments: ├── Server (recommended for RHCSA) ├── Minimal Install (command line only) ├── Workstation (desktop environment) ├── Custom Operating System (advanced users) └── Virtualization Host (for hypervisors)
Storage Configuration
Automatic partitioning: Simple, good for learning
Custom partitioning: More control, better for production
Network Configuration
Configure hostname
Set up network interfaces
Configure static IP if needed
User Configuration
Set root password (required)
Create regular user account (recommended)
Configure sudo access
Begin Installation
Review settings summary
Start installation process
Configure users while installation proceeds

Recommended Partitioning Scheme¶

# For RHCSA practice (20GB disk):
/boot     1GB   (ext4)    # Boot files and kernels
/         18GB  (xfs)     # Root filesystem
swap      1GB   (swap)    # Virtual memory

# For production environments:
/boot     1GB   (ext4)    # Boot files
/         10GB  (xfs)     # Root filesystem  
/home     5GB   (xfs)     # User data
/var      3GB   (xfs)     # Variable data (logs, etc.)
swap      1GB   (swap)    # Virtual memory

Base Environment Comparison¶

Environment	Size	GUI	Services	Use Case
Server	~3GB	No	Standard server services	RHCSA practice, production servers
Minimal	~1GB	No	Essential only	Containers, embedded systems
Workstation	~5GB	Yes	Desktop services	Development, desktop use

5. Configuration Deep Dive¶

Anaconda Installation Configuration¶

During installation, Anaconda creates several key configuration files:

Network Configuration¶

# /etc/hostname
server1.example.com

User Configuration¶

# /etc/passwd (user entries created)
root:x:0:0:root:/root:/bin/bash
user1:x:1000:1000:User One:/home/user1:/bin/bash

Filesystem Configuration¶

# /etc/fstab (automatically generated)
/dev/mapper/rhel-root   /       xfs     defaults        0 0
UUID=abc123-def456      /boot   ext4    defaults        1 2
/dev/mapper/rhel-swap   swap    swap    defaults        0 0

Post-Installation Configuration Files¶

System Information¶

# /etc/os-release
NAME="Red Hat Enterprise Linux"
VERSION="9.1 (Plow)"
ID="rhel"
VERSION_ID="9.1"
PLATFORM_ID="platform:el9"

Installed Package Information¶

# View installation log
cat /var/log/anaconda/anaconda.log

# List packages installed during installation
dnf history info 1

6. Hands-On Labs¶

Lab 6.1: Basic RHEL Installation (Asghar Ghori Method)¶

Objective: Install RHEL 9 with standard configuration for RHCSA practice

Prerequisites: - RHEL 9 ISO image - Virtual machine with 20GB disk, 2GB RAM - Network connectivity

Steps: 1. Create Virtual Machine bash # In VirtualBox/VMware: # - Name: rhel9-server1 # - RAM: 2048MB # - Disk: 20GB dynamically allocated # - Network: NAT or Bridged

Boot Installation Media
Attach RHEL 9 ISO to VM
Boot from ISO
Select "Install Red Hat Enterprise Linux 9.x"
Configure Installation
Language: English (US)
Software Selection: Server
Installation Destination: Use entire disk, automatic partitioning
Network Configuration
Set hostname: server1.example.com
Configure network interface with DHCP or static IP
User Configuration
Root password: Set secure password
Create user: Regular user with sudo privileges
Complete Installation
Review summary and begin installation
Wait for completion (20-30 minutes)
Reboot system

Verification:

# After reboot, verify installation
hostnamectl                    # Check hostname
cat /etc/os-release           # Verify RHEL version
lsblk                         # Check disk partitioning
ip addr show                  # Verify network configuration
systemctl status              # Check system status

Lab 6.2: Custom Partitioning Installation (Sander van Vugt Method)¶

Objective: Install RHEL 9 with custom partitioning scheme

Steps: 1. Follow initial steps from Lab 6.1 through software selection

Custom Storage Configuration
Installation Destination → Custom → Done
Create new mount points: /boot 1GB ext4 / 10GB xfs /home 5GB xfs /var 3GB xfs swap 1GB swap
Configure each partition: bash # For each mount point: # - Click "+" to add mount point # - Specify mount point and size # - Select filesystem type # - Click "Add mount point"
Complete installation following remaining steps from Lab 6.1

Verification:

# Verify custom partitioning
lsblk                         # Check partition layout
df -h                         # Check filesystem usage
cat /etc/fstab               # Verify fstab entries
mount | grep "^/" | sort     # List mounted filesystems

Lab 6.3: Post-Installation Configuration¶

Objective: Configure newly installed system for RHCSA practice

Steps: 1. System Updates ```bash # Register system (if using RHEL subscription) subscription-manager register --username your_username

# Update all packages dnf update -y ```

Additional Software Installation bash # Install useful tools for RHCSA practice dnf groupinstall "Development Tools" -y dnf install vim wget curl man-pages -y
Security Configuration ```bash # Configure firewall firewall-cmd --state firewall-cmd --list-all

# Enable SELinux (verify) getenforce ```

User Environment bash # Configure bash aliases for root echo 'alias ll="ls -la"' >> /root/.bashrc echo 'alias grep="grep --color=auto"' >> /root/.bashrc

Verification:

# Verify post-installation configuration
dnf list installed | wc -l   # Count installed packages
systemctl list-unit-files --state=enabled | wc -l  # Count enabled services
firewall-cmd --list-all       # Check firewall status
getenforce                    # Verify SELinux status

7. Troubleshooting Playbook¶

Common Installation Issues¶

Issue 1: Installation Media Not Detected¶

Symptoms: - Boot process hangs or shows errors - "No installation source found" message

Diagnosis:

# Check ISO integrity before installation
sha256sum /path/to/rhel-9.x-x86_64-dvd.iso
# Compare with official checksum from Red Hat

Resolution: - Re-download ISO image if corrupted - Verify virtual machine CD/DVD settings - Try different boot order in BIOS/UEFI

Prevention: Always verify ISO checksums before installation

Issue 2: Insufficient Disk Space¶

Symptoms: - "Not enough space" error during partitioning - Installation fails during package installation

Diagnosis:

# In installer, check available disk space
# Minimum requirements:
# - Server: 3GB
# - Workstation: 5GB
# - Recommended: 20GB+ for practice

Resolution: - Increase virtual machine disk size - Choose Minimal Install if space limited - Use custom partitioning to optimize space usage

Issue 3: Network Configuration Problems¶

Symptoms: - Cannot set hostname - Network interface not detected - No network connectivity post-installation

Diagnosis:

# During installation, check network tab
# Post-installation:
ip link show                  # Check if interfaces exist
ip addr show                  # Check IP configuration

Resolution:

# Post-installation network fix:
nmcli connection show
nmcli connection up "interface-name"
systemctl restart NetworkManager

Boot Issues After Installation¶

Issue 4: System Won't Boot¶

Symptoms: - GRUB rescue prompt - Kernel panic messages - Black screen after boot

Diagnosis:

# From rescue media:
mkdir /mnt/sysimage
mount /dev/mapper/rhel-root /mnt/sysimage
chroot /mnt/sysimage

Resolution:

# Reinstall GRUB bootloader
grub2-install /dev/sda
grub2-mkconfig -o /boot/grub2/grub.cfg

8. Quick Reference Card¶

Essential Installation Commands¶

# Pre-installation verification
lscpu                    # Check CPU
free -h                  # Check memory
lsblk                    # Check storage

# Post-installation verification  
hostnamectl              # System info
uname -a                 # Kernel info
df -h                    # Storage usage
ip addr show             # Network config

Key File Locations¶

Installation logs: /var/log/anaconda/
System configuration: /etc/os-release
Filesystem mounts: /etc/fstab
Network configuration: /etc/NetworkManager/

Installation Options¶

Graphical: Default installation interface
Text mode: Add inst.text to boot parameters
VNC: Add inst.vnc for remote installation
Kickstart: Add inst.ks=URL for automated installation

Verification Commands¶

# Quick system health check
systemctl status         # System status
journalctl -b           # Boot messages
dmesg | tail           # Kernel messages

9. Knowledge Check¶

Conceptual Questions¶

Question: What is the name of the RHEL installer program? Answer: Anaconda - this is the graphical and text-based installer used for all RHEL installations.
Question: What are the minimum partition requirements for RHEL installation? Answer: Root filesystem (/) and swap partition. While /boot is recommended as separate partition, it can reside within the root filesystem in simple installations.
Question: What is the difference between Server and Minimal Install base environments? Answer: Server includes standard server services and networking tools (~3GB), while Minimal Install contains only essential packages for basic system operation (~1GB).

Practical Scenarios¶

Scenario: You need to install RHEL on a system with only 10GB available disk space. Solution: Use Minimal Install base environment, create 8GB root partition and 2GB swap, or use custom partitioning to optimize space allocation.
Scenario: Installation completed but system won't boot, showing GRUB rescue prompt. Solution: Boot from installation media in rescue mode, chroot to installed system, reinstall GRUB bootloader using grub2-install and grub2-mkconfig commands.

Command Challenges¶

Challenge: Write commands to verify a successful RHEL installation. Answer: bash hostnamectl # Check system info cat /etc/os-release # Verify RHEL version lsblk && df -h # Check storage ip addr show # Verify network systemctl status # Check system health

10. Exam Strategy¶

Topic-Specific Tips¶

Installation knowledge helps with boot troubleshooting tasks
Understand default partitioning schemes for storage questions
Know post-installation configuration locations
Practice both graphical and text-mode installations

Common Exam Scenarios¶

Scenario: Fix boot issues on system that won't start Approach: Use rescue mode, check /boot contents, verify GRUB configuration
Scenario: Configure hostname during system setup Approach: Use hostnamectl set-hostname command, verify with hostnamectl status

Time Management¶

Installation tasks: Usually 5-10 minutes for configuration
Boot troubleshooting: Allocate 15-20 minutes maximum
Quick verification: Use fast commands like hostnamectl, lsblk

Pitfalls to Avoid¶

Don't spend excessive time on installation details during exam
Remember to make configuration changes persistent
Always verify system boots correctly after changes
Check both current state and persistent configuration

Summary¶

Key Takeaways¶

Anaconda is the RHEL installer program with graphical and text interfaces
Server base environment is ideal for RHCSA practice and exam preparation
Standard partitioning includes root (/) and swap at minimum, /boot recommended
Post-installation verification ensures system is properly configured

Critical Commands to Remember¶

hostnamectl                 # System information and hostname management
lsblk                      # Display block devices and partitions
systemctl status           # Check system and service status

Next Steps¶

Continue to Module 02: File Management
Practice installation in virtual environment using Vagrant
Review related topics: Boot Process, Storage

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