01 - System Installation & Initial Configuration

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1. Executive Summary

Topic Scope: RHEL 10 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

  1. Boot from Installation Media

    • Select "Install Red Hat Enterprise Linux 9.x"
    • Wait for Anaconda to load (may take several minutes)

  2. Language and Localization

    • Select installation language
    • Configure keyboard layout
    • Set date and time/timezone

  3. Installation Source

    • Verify installation media is detected
    • Configure additional repositories if needed

  4. 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)

  5. Storage Configuration

    • Automatic partitioning: Simple, good for learning
    • Custom partitioning: More control, better for production

  6. Network Configuration

    • Configure hostname
    • Set up network interfaces
    • Configure static IP if needed

  7. User Configuration

    • Set root password (required)
    • Create regular user account (recommended)
    • Configure sudo access

  8. Begin Installation

    • Review settings summary
    • Start installation process
    • Configure users while installation proceeds
# 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 10 with standard configuration for RHCSA practice

Prerequisites:

  • RHEL 10 ISO image
  • Virtual machine with 20GB disk, 2GB RAM
  • Network connectivity

Steps:

  1. Create Virtual Machine

    # In VirtualBox/VMware:
# - Name: rhel10-server1
# - RAM: 2048MB
# - Disk: 20GB dynamically allocated
# - Network: NAT or Bridged

  2. Boot Installation Media

    • Attach RHEL 10 ISO to VM
    • Boot from ISO
    • Select "Install Red Hat Enterprise Linux 9.x"

  3. Configure Installation

    • Language: English (US)
    • Software Selection: Server
    • Installation Destination: Use entire disk, automatic partitioning

  4. Network Configuration

    • Set hostname: server1.example.com
    • Configure network interface with DHCP or static IP

  5. User Configuration

    • Root password: Set secure password
    • Create user: Regular user with sudo privileges

  6. 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 10 with custom partitioning scheme

Steps:

  1. Follow initial steps from Lab 6.1 through software selection

  2. 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

  3. Configure each partition:

    # For each mount point:
# - Click "+" to add mount point
# - Specify mount point and size
# - Select filesystem type
# - Click "Add mount point"

  4. 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

    # Register system (if using RHEL subscription)
subscription-manager register --username your_username

# Update all packages
dnf update -y

  2. Additional Software Installation

    # Install useful tools for RHCSA practice
dnf groupinstall "Development Tools" -y
dnf install vim wget curl man-pages -y

  3. Security Configuration

    # Configure firewall
firewall-cmd --state
firewall-cmd --list-all

# Enable SELinux (verify)
getenforce

  4. User Environment

    # 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

  1. 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.

  2. 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.

  3. 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

  1. 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.

  2. 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

  1. Challenge: Write commands to verify a successful RHEL installation. Answer:

    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

  1. Scenario: Fix boot issues on system that won't start Approach: Use rescue mode, check /boot contents, verify GRUB configuration

  2. 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

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