RHEL VM Creation Script

Automated RHEL VM creation tool using KVM/QEMU with cloud-init configuration. This script streamlines the process of creating virtual machines from RHEL template images with automatic user configuration, SSH key setup, and customizable resources.

Features

• Automatic image discovery - Finds the latest RHEL image from _RAW/<Date>/ directories
• Cloud-init integration - Automated user creation, SSH key setup, and system configuration
• User convenience - Uses your current username and SSH public key automatically
• Secure password handling - Interactive password prompt (no hardcoded defaults); supports SSH key-only mode
• Resource customization - Configure memory, vCPUs, and network settings
• Multiple RHEL versions - Supports RHEL 8, 9, and 10
• Dry-run mode - Preview what will be created without making changes
• Optional package installation - Control whether packages are installed during boot

Requirements

Hardware

• A CPU with hardware virtualisation support (Intel VT-x or AMD-V)

Verify it is enabled:

grep -Ec '(vmx|svm)' /proc/cpuinfo
# Output > 0 means virtualisation is available

Host OS

The script is designed for Fedora / RHEL / CentOS Stream hosts. The commands below use dnf.

Software dependencies

Installation (Fedora / RHEL)

# Core requirements
sudo dnf install -y python3 openssl qemu-kvm libvirt libvirt-client virt-install
# Optional: disk resize support
sudo dnf install -y qemu-img
# Optional: graphical VM manager
sudo dnf install -y virt-manager
# Enable and start the virtualisation daemon
sudo systemctl enable --now libvirtd

Verify the setup:

# Check libvirtd is running
sudo systemctl status libvirtd
# Check virt-install is available
virt-install --version
# Check openssl supports SHA-512 crypt (should print a 6ドル$ hash)
echo test | openssl passwd -6 -stdin

RHEL template images

Place downloaded RHEL KVM guest images in _RAW/<YYYY-MM-DD>/:

_RAW/
└── 2026年01月02日/
 ├── rhel-8.10-x86_64-kvm.qcow2
 ├── rhel-9.7-x86_64-kvm.qcow2
 └── rhel-10.1-x86_64-kvm.qcow2

Images can be downloaded from Red Hat Customer Portal (requires a Red Hat account or active subscription).

SSH key

An SSH public key in ~/.ssh/ is strongly recommended (ed25519, RSA, or ECDSA). Without one, a console password is required to access the VM. Generate a key if needed:

ssh-keygen -t ed25519 -C "your_email@example.com"

Quick Start

Create a basic RHEL 10 VM:

./create_vm.py --rhel 10 --hostname rhel10-lab01

This will:

1. Find the latest RHEL 10 image
2. Create a rhel10-lab01/ directory
3. Prompt you to choose SSH key-only login or set a console password
4. Generate cloud-init configuration files
5. Copy the disk image
6. Create and start the VM

Command-Line Options

Required Arguments

Image Selection (Optional)

Optional Arguments

Usage Examples

Basic VM Creation

./create_vm.py --rhel 10 --hostname rhel10-lab01

VM with FQDN

./create_vm.py --rhel 9 --hostname rhel9-web01.example.com

Custom Resources

./create_vm.py --rhel 10 --hostname rhel10-db01 --memory 8192 --vcpus 4

Specific Minor Version

# Use RHEL 10.0 instead of the latest 10.x
./create_vm.py --rhel 10 --minor 0 --hostname rhel10-lab01
# Use RHEL 9.4 specifically
./create_vm.py --rhel 9 --minor 4 --hostname rhel9-web01

Specific Image File

# Use a specific qcow2 image directly
./create_vm.py --rhel 10 --image /path/to/custom-rhel10.qcow2 --hostname rhel10-custom

Custom Disk Size

# 50 GB disk
./create_vm.py --rhel 10 --hostname rhel10-lab01 --disk-size 50
# 100 GB disk with more resources
./create_vm.py --rhel 10 --hostname rhel10-db01 --memory 8192 --vcpus 4 --disk-size 100

Note: If --disk-size is not specified, the VM uses the original template image size.

Custom Network

./create_vm.py --rhel 8 --hostname rhel8-test --network bridge=br0

Custom Timezone

./create_vm.py --rhel 10 --hostname rhel10-lab01 --timezone America/New_York
./create_vm.py --rhel 9 --hostname rhel9-web01 --timezone Asia/Tokyo
./create_vm.py --rhel 10 --hostname rhel10-db01 --timezone UTC

Custom CA Certificate

# Install a custom root CA certificate on first boot
./create_vm.py --rhel 10 --hostname rhel10-lab01 --ca-url https://pki.example.com/root-ca.crt

The certificate will be downloaded to /etc/pki/ca-trust/source/anchors/ and update-ca-trust will be run automatically during cloud-init.

Custom SSH Key

# Use a specific SSH key instead of the auto-detected one
./create_vm.py --rhel 10 --hostname rhel10-lab01 --ssh-key ~/.ssh/id_ed25519.pub
# Useful when your default key differs from what you want on the VM
./create_vm.py --rhel 9 --hostname rhel9-web01 --ssh-key /path/to/team-key.pub

Note: When --ssh-key is specified, auto-detection of keys from ~/.ssh/ is skipped entirely.

With Package Installation

./create_vm.py --rhel 10 --hostname rhel10-lab01 --install-packages

Note: Package installation requires repository access. Without --install-packages, packages can be installed manually after boot to avoid cloud-init failures.

Dry Run Example

Test without creating the VM:

./create_vm.py --rhel 10 --hostname rhel10-lab01 --memory 8192 --vcpus 4 --dry-run

Output:

============================================================
RHEL VM Creation Script
============================================================
RHEL Version: 10
VM Name: rhel10-lab01
Hostname: rhel10-lab01
Memory: 8192 MB
vCPUs: 4
Network: default
============================================================
Step 1: Locating source disk image...
Found: _RAW/2026-01-02/rhel-10.1-x86_64-kvm.qcow2
Step 2: Creating VM directory...
Created: /home/user/VirtualMachines/rhel10-lab01
Step 3: Creating cloud-init configuration files...
Created: rhel10-lab01/user-data.yaml
Created: rhel10-lab01/meta-data.yaml
Step 4: Copying disk image...
Copying disk image...
 From: _RAW/2026-01-02/rhel-10.1-x86_64-kvm.qcow2
 To: rhel10-lab01/rhel-10.1-x86_64-kvm.qcow2
Disk image copied successfully
DRY RUN MODE - VM creation skipped
To create the VM manually, run:
sudo virt-install --name rhel10-lab01 --memory 8192 --vcpus 4 \
 --disk path=rhel10-lab01/rhel-10.1-x86_64-kvm.qcow2 --import --os-variant rhel10.0 \
 --network network=default --graphics spice \
 --cloud-init user-data=rhel10-lab01/user-data.yaml,meta-data=rhel10-lab01/meta-data.yaml

What Gets Created

For a VM named rhel10-lab01, the script creates:

rhel10-lab01/
├── rhel-10.1-x86_64-kvm.qcow2 # Disk image (copy from _RAW)
├── user-data.yaml # Cloud-init user configuration
└── meta-data.yaml # Cloud-init metadata

Authentication modes

When the script runs, it prompts you to choose how the VM user can log in:

Option 1 — SSH key only (recommended)

An SSH key is configured. Choose login method:
 1) SSH key only (recommended — no console password set)
 2) SSH key + console password
Choice [1/2, default 1]:

• Password login is disabled; the account is locked
• ssh_pwauth is set to False in cloud-init
• Console (virsh console) requires an alternative method to recover access (e.g. re-running the script or editing the image offline)

Option 2 — SSH key + console password

• You are prompted to enter and confirm a password (minimum 8 characters, no newlines)
• The password is hashed with SHA-512 crypt (openssl passwd -6) before being written to user-data.yaml — the plaintext password is never stored anywhere
• Both SSH key and password authentication are enabled

If no SSH key is found, a password is always required.

user-data.yaml Configuration

The generated cloud-init configuration includes:

• User account: Your current username (from $USER)
• Password: Entered interactively and stored as a SHA-512 hash; or account locked (SSH key-only mode)
• SSH key: Key specified via --ssh-key, or auto-detected from ~/.ssh/
• Sudo access: Passwordless sudo enabled
• Timezone: System timezone (customizable with --timezone)
• SSH access: Key-based always; password authentication only if a password was set
• Root account: Disabled for security
• Packages: Optional (disabled by default to avoid cloud-init failures)

Accessing Your VM

SSH Access (Primary Method)

# Get VM IP address
sudo virsh domifaddr rhel10-lab01
# Connect via SSH (uses your SSH key automatically)
ssh user@<vm-ip>

Console Access (Fallback)

# Connect to VM console
sudo virsh console rhel10-lab01

Login with the username printed at the end of the script and the password you entered during setup. If you chose SSH key-only mode, console password login is disabled — use SSH instead.

To exit the console, press Ctrl+]

VM Management

List VMs

# List all VMs
sudo virsh list --all
# List running VMs only
sudo virsh list

Control VMs

# Start a VM
sudo virsh start rhel10-lab01
# Stop a VM gracefully
sudo virsh shutdown rhel10-lab01
# Force stop a VM
sudo virsh destroy rhel10-lab01
# Delete a VM (keeps disk files)
sudo virsh undefine rhel10-lab01
# Delete a VM and its disk
sudo virsh undefine rhel10-lab01 --remove-all-storage

VM Information

# Get VM info
sudo virsh dominfo rhel10-lab01
# Get VM IP address
sudo virsh domifaddr rhel10-lab01
# View VM console output
sudo virsh console rhel10-lab01

Directory Structure

VirtualMachines/
├── _RAW/ # Template images (gitignored)
│ └── 2026年01月02日/
│ ├── rhel-8.10-x86_64-kvm.qcow2
│ ├── rhel-9.7-x86_64-kvm.qcow2
│ └── rhel-10.1-x86_64-kvm.qcow2
├── rhel10-lab01/ # VM directory (gitignored)
│ ├── rhel-10.1-x86_64-kvm.qcow2
│ ├── user-data.yaml
│ └── meta-data.yaml
├── create_vm.py # Main script
├── .gitignore # Excludes sensitive files
└── README.md # This file

Troubleshooting

Cloud-init Failures

Problem: cloud-final.service fails during boot

Cause: Package installation fails due to missing repository access

Solution: Don't use --install-packages flag. Install packages manually after boot:

ssh user@<vm-ip>
sudo dnf install vim wget curl git

SSH Key Not Found

Problem: Warning about missing SSH public key

Solution: Either generate an SSH key pair, or specify a key path explicitly with --ssh-key:

# Generate ed25519 key (recommended)
ssh-keygen -t ed25519 -C "your_email@example.com"
# Or generate RSA key
ssh-keygen -t rsa -b 4096 -C "your_email@example.com"
# Or point to an existing key directly
./create_vm.py --rhel 10 --hostname rhel10-lab01 --ssh-key /path/to/key.pub

VM Already Exists

Problem: Directory already exists

Solution: The script will prompt you to overwrite. You can also manually remove the directory:

rm -rf rhel10-lab01/

Can't Find VM After Creation

Problem: VM not showing in virsh list

Solution: Check if it's stopped:

sudo virsh list --all
sudo virsh start rhel10-lab01

Network Issues

Problem: Can't get VM IP address

Solution: Check network and restart VM:

# Check network
sudo virsh net-list --all
sudo virsh net-start default
# Restart VM
sudo virsh destroy rhel10-lab01
sudo virsh start rhel10-lab01

Security Considerations

• Passwords: No hardcoded defaults — you set the password interactively, or choose SSH key-only mode. Passwords are hashed with SHA-512 crypt before being written to cloud-init files; the plaintext is never stored
• SSH Keys: Only your SSH key is added to the VM
• Root Access: Root login is disabled by default
• Firewall: Configure firewall rules as needed for your use case
• Updates: Remember to apply security updates regularly

Version Control

The .gitignore file is configured to exclude:

• Cloud-init files (contain passwords and SSH keys)
• Disk images (large binary files)
• VM directories
• RAW image directories

Only the script and documentation are version controlled.

Manual Package Installation

If you didn't use --install-packages, install common packages after boot:

# Connect to VM
ssh user@<vm-ip>
# Install common utilities
sudo dnf install -y vim wget curl git
# Install development tools
sudo dnf groupinstall -y "Development Tools"
# Install specific packages as needed
sudo dnf install -y htop tmux tree

Advanced Usage

Using Different Networks

# Bridge network
./create_vm.py --rhel 10 --hostname rhel10-lab01 --network bridge=br0
# Custom network
./create_vm.py --rhel 10 --hostname rhel10-lab01 --network network=custom-net

Large VMs for Database Workloads

./create_vm.py --rhel 10 --hostname rhel10-db01 \
 --memory 16384 \
 --vcpus 8 \
 --disk-size 200

Development VMs

./create_vm.py --rhel 9 --hostname rhel9-dev01 \
 --memory 8192 \
 --vcpus 4

Help

View all available options:

./create_vm.py --help

License

This project is licensed under the MIT License.

Lab icons created by Nhor Phai - Flaticon

Contributing

To add features or fix issues:

1. Test changes with --dry-run first
2. Update this README if adding new options
3. Ensure .gitignore excludes sensitive files