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RHCE Vagrant Lab Environment

Minimal lab environment for Red Hat Certified Engineer (RHCE) exam preparation using Vagrant and Ansible. This setup creates a clean multi-node environment for practicing Ansible automation from scratch.

Overview

This Vagrant configuration creates 5 RHEL 9 VMs:

VM Name IP Address RAM Role Purpose
control 192.168.4.200 2GB Control Node Clean RHEL system for Ansible practice
ansible1 192.168.4.201 1GB Managed Node Target system for automation practice
ansible2 192.168.4.202 1GB Managed Node Target system for automation practice
ansible3 192.168.4.203 1GB Managed Node Target system for automation practice
ansible4 192.168.4.204 1GB Managed Node Target system for automation practice

Prerequisites

Required Software

  • Vagrant (≥2.3.0) - VM management
  • VirtualBox - Hypervisor
  • Red Hat Developer Account - Free at developers.redhat.com

Vagrant Plugins

The lab setup will automatically install required plugins:

  • vagrant-registration - Red Hat subscription management

System Requirements

  • RAM: 6GB minimum (8GB recommended)
  • Disk: 25GB free space for all VMs
  • CPU: 4+ cores recommended
  • Network: Internet access for initial setup

Quick Start

1. Setup Credentials

# Copy credentials template
cp .rhel-credentials.template .rhel-credentials

# Edit with your Red Hat Developer account
vim .rhel-credentials

2. Start Lab Environment

# Start all VMs and configure automatically
./lab.sh up

This will:

  • Create and start all 5 VMs
  • Register with Red Hat subscription
  • Create ansible user with sudo privileges
  • Set up SSH key authentication between nodes
  • Configure basic networking (/etc/hosts)
  • Install essential packages only

3. Access Control Node

# SSH to the control node
vagrant ssh control

# Switch to ansible user (configured with passwordless sudo)
sudo su - ansible

# Test connectivity to all managed nodes
ansible all -m ping

Lab Management

Start/Stop Operations

./lab.sh up       # Start all VMs (initial setup ~15 minutes)
./lab.sh halt     # Stop all VMs gracefully
./lab.sh destroy  # Destroy all VMs (does not recreate)
./lab.sh status   # Show current VM status

Individual VM Management

vagrant status                    # Show all VM status
vagrant ssh control              # SSH to control node
vagrant ssh ansible1            # SSH to managed node
vagrant halt ansible2           # Stop specific VM
vagrant up ansible3 --provision # Start and re-provision

Ansible Configuration

Pre-configured Setup

The lab automatically configures:

  • Ansible User: ansible user on all VMs with sudo privileges
  • SSH Keys: Passwordless authentication from control to managed nodes
  • Inventory: Default inventory with logical host groups
  • Configuration: Optimized ansible.cfg for lab environment
  • Collections: Essential Ansible collections pre-installed

Default Inventory Groups

[control]
control.example.com

[webservers]
ansible1.example.com
ansible2.example.com

[databases]
ansible3.example.com

[development]
ansible4.example.com

[production:children]
webservers
databases

Project Structure

The control node includes organized directories:

/home/ansible/
├── inventory           # Default inventory file
├── .ansible.cfg        # User-specific configuration
├── projects/           # Practice project directories
│   ├── webservers/     # Web server automation
│   ├── databases/      # Database management
│   └── practice/       # General practice exercises
└── .ssh/
    └── id_rsa         # SSH private key for managed nodes

RHCE Practice Scenarios

Web Server Automation (ansible1, ansible2)

  • Apache HTTP Server installation and configuration
  • Template deployment for configuration files
  • Service management and handler implementation
  • Firewall configuration for web services

Database Management (ansible3)

  • MariaDB installation and configuration
  • Database and user creation
  • Backup and restore procedures
  • Security configuration

Development Environment (ansible4)

  • Development tools installation
  • Git repository management
  • Application deployment
  • Testing and validation

Multi-Node Scenarios

  • Load balancer configuration
  • Cross-node service dependencies
  • Rolling updates and deployments
  • Monitoring and logging aggregation

Common Commands

Connectivity Testing

# From control node as ansible user
ansible all -m ping                    # Test all nodes
ansible webservers -m setup           # Gather facts from web servers
ansible databases -m service -a "name=mariadb state=started"

Inventory Management

ansible-inventory --list               # Show full inventory
ansible-inventory --graph             # Show inventory tree
ansible-inventory --host control      # Show host variables

Playbook Development

ansible-playbook site.yml --check     # Dry run
ansible-playbook site.yml --syntax-check  # Validate syntax
ansible-playbook site.yml -v          # Verbose output
ansible-playbook site.yml --limit webservers  # Target specific group

Troubleshooting

Common Issues

VMs won't start

# Check Vagrant status
vagrant status

# Check VirtualBox VMs
VBoxManage list runningvms

# Restart VirtualBox service (Linux)
sudo systemctl restart virtualbox

SSH connectivity issues

# From control node, test SSH manually
ssh ansible@ansible1.example.com

# Check SSH keys
ls -la ~/.ssh/
cat ~/.ssh/id_rsa.pub

# Regenerate keys if needed
ssh-keygen -t rsa -b 2048 -f ~/.ssh/id_rsa

Ansible connectivity problems

# Check ansible configuration
ansible-config dump

# Test with verbose output
ansible all -m ping -vvv

# Verify inventory
ansible-inventory --list

Provisioning failures

# Re-run provisioning only
vagrant provision

# Re-run specific parts
vagrant provision --provision-with ansible

# Check provisioning logs
tail -f /tmp/ansible.log

Reset Procedures

Soft Reset (keep VMs, re-run provisioning):

vagrant provision

Hard Reset (destroy and recreate):

./lab.sh destroy
./lab.sh up

Individual VM Reset:

vagrant destroy ansible1
vagrant up ansible1

Integration with Study Materials

This lab environment is designed to work with:

  • Online Documentation: kraker.github.io/rhce
  • Study Modules: Practice exercises from docs/rhce_synthesis/
  • Anki Flashcards: Hands-on validation of memorized commands
  • Practice Playbooks: Real automation scenarios

Security Notes

  • Lab uses private network (192.168.4.0/24) isolated from external access
  • SSH host key checking disabled for lab convenience (NOT for production)
  • Ansible user has passwordless sudo (lab-only configuration)
  • Red Hat credentials stored locally and not tracked in git

Performance Optimization

Resource Allocation

  • Control node: 2GB RAM (runs Ansible controller)
  • Managed nodes: 1GB RAM each (sufficient for practice)
  • Adjust in Vagrantfile if more resources needed

Network Performance

  • Private network for fast inter-VM communication
  • Host-only networking prevents external access
  • SSH connection multiplexing enabled

Storage

  • Base VM disk: 20GB (auto-expanding)
  • Additional 1GB disk per VM for storage exercises
  • Snapshot support for quick reset scenarios

Need Help?