Advanced Configuration

Complete guide for advanced configuration and customization of NazDocker Lab.

⚙️ Startup Script Management

The lab environment uses a modularized startup script (start.sh) that handles:

  • User account creation and password management
  • SSH service initialization
  • Playit.gg tunnel setup
  • Home directory permissions

Modifying the Startup Script 

# Edit the startup script
nano start.sh

# Rebuild container after changes
docker-compose -f docker-compose.ubuntu.yml up -d --build

# View startup script logs
docker-compose -f docker-compose.ubuntu.yml logs lab-environment-ubuntu | grep -i "start\|ssh\|playit"

Startup Script Functions

  • User Management: Creates and configures all user accounts
  • Password Configuration: Sets passwords from environment variables
  • SSH Setup: Starts and configures SSH service
  • Tunnel Management: Initializes playit.gg tunneling
  • Service Monitoring: Keeps container running with health checks

Startup Script Analysis 

# View startup script
cat start.sh

# Check startup script permissions
ls -la start.sh

# Test startup script syntax
bash -n start.sh

# Run startup script manually (for testing)
docker-compose -f docker-compose.ubuntu.yml exec lab-environment-ubuntu bash /start.sh

🔧 Customizing the Container

Adding Additional Packages

Method 1: Running Container 

# Access container
docker-compose -f docker-compose.ubuntu.yml exec lab-environment-ubuntu bash

# Update package list
apt-get update

# Install packages
apt-get install -y package_name

# Clean up
apt-get autoremove -y
apt-get clean

Method 2: Dockerfile Modification 

# Add to Dockerfile.ubuntu
RUN apt-get update && apt-get install -y \
    package1 \
    package2 \
    && rm -rf /var/lib/apt/lists/*

Method 3: Custom Installation Script 

# Create custom installation script
cat > install-tools.sh << 'EOF'
#!/bin/bash
apt-get update
apt-get install -y htop vim nano curl wget git
apt-get autoremove -y
apt-get clean
EOF

# Copy to container and execute
docker cp install-tools.sh student-lab-ubuntu:/tmp/
docker-compose -f docker-compose.ubuntu.yml exec lab-environment-ubuntu bash /tmp/install-tools.sh

# Make script executable
chmod +x install-tools.sh

Custom Scripts

Development Tools Installation 

# Create development tools script
cat > install-dev-tools.sh << 'EOF'
#!/bin/bash
echo "Installing development tools..."

# Python development
apt-get update
apt-get install -y python3-dev python3-pip python3-venv

# Node.js development
apt-get install -y nodejs npm

# Build tools
apt-get install -y build-essential cmake

# Development utilities
apt-get install -y git vim nano htop curl wget

# Clean up
apt-get autoremove -y
apt-get clean

echo "Development tools installation completed"
EOF

# Execute script
docker cp install-dev-tools.sh student-lab-ubuntu:/tmp/
docker-compose -f docker-compose.ubuntu.yml exec lab-environment-ubuntu bash /tmp/install-dev-tools.sh

Security Tools Installation 

# Create security tools script
cat > install-security-tools.sh << 'EOF'
#!/bin/bash
echo "Installing security tools..."

# Security utilities
apt-get update
apt-get install -y fail2ban ufw auditd

# Monitoring tools
apt-get install -y htop iotop nethogs

# Network tools
apt-get install -y net-tools nmap tcpdump

# Clean up
apt-get autoremove -y
apt-get clean

echo "Security tools installation completed"
EOF

# Execute script
docker cp install-security-tools.sh student-lab-ubuntu:/tmp/
docker-compose -f docker-compose.ubuntu.yml exec lab-environment-ubuntu bash /tmp/install-security-tools.sh

📈 Performance Optimization

Resource Limits

Docker Compose Resource Configuration 

# In docker-compose.ubuntu.yml
services:
  lab-environment-ubuntu:
    deploy:
      resources:
        limits:
          cpus: '2.0'
          memory: 2G
        reservations:
          cpus: '1.0'
          memory: 1G

Current Configuration:

  • CPU Limits: Maximum 2 cores, minimum 1 core reserved
  • Memory Limits: Maximum 2GB, minimum 1GB reserved
  • Network: Standard bridge networking
  • Storage: Persistent volumes for user data

Custom Resource Limits 

# Custom resource configuration
services:
  lab-environment-ubuntu:
    deploy:
      resources:
        limits:
          cpus: '4.0'      # 4 CPU cores
          memory: 4G        # 4GB RAM
        reservations:
          cpus: '2.0'       # 2 CPU cores reserved
          memory: 2G        # 2GB RAM reserved

Volume Optimization

Optimized Volume Configuration 

# In docker-compose.ubuntu.yml
volumes:
  - ./data:/home:delegated
  - ./logs:/var/log:delegated
  - ./config:/etc/ssh:ro

Volume Performance Options 

# Performance-optimized volumes
volumes:
  - ./data:/home:cached      # For read-heavy workloads
  - ./logs:/var/log:delegated # For write-heavy workloads
  - ./config:/etc/ssh:ro     # Read-only configuration

Container Optimization

Multi-stage Build Optimization 

# Optimized Dockerfile
FROM ubuntu:24.04 as base

# Install essential packages
RUN apt-get update && apt-get install -y \
    openssh-server \
    sudo \
    curl \
    wget \
    && rm -rf /var/lib/apt/lists/*

# Create users
RUN useradd -m -s /bin/bash admin && \
    echo "admin:admin123" | chpasswd && \
    usermod -aG sudo admin

# Copy startup script
COPY start.sh /start.sh
RUN chmod +x /start.sh

# Health check
HEALTHCHECK --interval=30s --timeout=10s --start-period=40s --retries=3 \
    CMD service ssh status || exit 1

# Expose SSH port
EXPOSE 22

# Start services
CMD ["/start.sh"]

🌐 Network Configuration

Custom Network Setup

Bridge Network Configuration 

# In docker-compose.ubuntu.yml
networks:
  lab-network:
    driver: bridge
    ipam:
      config:
        - subnet: 172.20.0.0/16

services:
  lab-environment-ubuntu:
    networks:
      - lab-network

Advanced Network Configuration 

# Advanced network setup
networks:
  lab-network:
    driver: bridge
    ipam:
      config:
        - subnet: 172.20.0.0/16
          gateway: 172.20.0.1
    driver_opts:
      com.docker.network.bridge.name: lab-bridge
    labels:
      - "com.example.some-label=some-value"

services:
  lab-environment-ubuntu:
    networks:
      lab-network:
        ipv4_address: 172.20.0.10

Network Security

Firewall Configuration 

# Configure UFW firewall
docker-compose -f docker-compose.ubuntu.yml exec lab-environment-ubuntu bash -c "
ufw default deny incoming
ufw default allow outgoing
ufw allow ssh
ufw allow 22
ufw --force enable
"

# Check firewall status
docker-compose -f docker-compose.ubuntu.yml exec lab-environment-ubuntu ufw status verbose

Network Isolation 

# Isolated network configuration
networks:
  lab-network:
    driver: bridge
    internal: true  # No external connectivity
    ipam:
      config:
        - subnet: 172.20.0.0/16

services:
  lab-environment-ubuntu:
    networks:
      - lab-network
    # Add external network for internet access
    networks:
      - lab-network
      - default

🔧 Advanced Customization

Environment-Specific Configuration

Development Environment 

# Development-specific configuration
services:
  lab-environment-ubuntu:
    environment:
      - NODE_ENV=development
      - DEBUG=true
      - LOG_LEVEL=debug
    volumes:
      - ./data:/home
      - ./logs:/var/log
      - ./dev-config:/etc/dev:ro

Production Environment 

# Production-specific configuration
services:
  lab-environment-ubuntu:
    environment:
      - NODE_ENV=production
      - DEBUG=false
      - LOG_LEVEL=warn
    deploy:
      resources:
        limits:
          cpus: '4.0'
          memory: 4G
    volumes:
      - ./data:/home
      - ./logs:/var/log
      - ./prod-config:/etc/prod:ro

Custom Health Checks

Advanced Health Check 

# Custom health check script
COPY health-check.sh /health-check.sh
RUN chmod +x /health-check.sh

HEALTHCHECK --interval=30s --timeout=10s --start-period=40s --retries=3 \
    CMD /health-check.sh

Health Check Script 

#!/bin/bash
# health-check.sh

# Check SSH service
if ! service ssh status > /dev/null 2>&1; then
    exit 1
fi

# Check SSH process
if ! pgrep sshd > /dev/null; then
    exit 1
fi

# Check network connectivity
if ! ping -c 1 google.com > /dev/null 2>&1; then
    exit 1
fi

# Check disk space
if [ $(df / | tail -1 | awk '{print $5}' | sed 's/%//') -gt 90 ]; then
    exit 1
fi

exit 0

📊 Performance Monitoring

Resource Monitoring Script 

#!/bin/bash
# performance-monitor.sh

echo "=== Performance Monitor ==="
echo ""

echo "1. Container Stats:"
docker stats --no-stream student-lab-ubuntu
echo ""

echo "2. System Resources:"
docker-compose -f docker-compose.ubuntu.yml exec lab-environment-ubuntu bash -c "
echo 'CPU Usage:'
top -bn1 | grep 'Cpu(s)'
echo 'Memory Usage:'
free -h
echo 'Disk Usage:'
df -h
"
echo ""

echo "3. Network Stats:"
docker-compose -f docker-compose.ubuntu.yml exec lab-environment-ubuntu bash -c "
netstat -i
"
echo ""

echo "4. Process List:"
docker-compose -f docker-compose.ubuntu.yml exec lab-environment-ubuntu bash -c "
ps aux --sort=-%cpu | head -10
"
echo ""

Optimization Scripts

Performance Tuning Script 

#!/bin/bash
# performance-tuning.sh

echo "=== Performance Tuning ==="
echo ""

echo "1. Updating package lists..."
docker-compose -f docker-compose.ubuntu.yml exec lab-environment-ubuntu apt-get update

echo "2. Installing performance tools..."
docker-compose -f docker-compose.ubuntu.yml exec lab-environment-ubuntu apt-get install -y htop iotop nethogs

echo "3. Optimizing system settings..."
docker-compose -f docker-compose.ubuntu.yml exec lab-environment-ubuntu bash -c "
# Optimize memory settings
echo 'vm.swappiness=10' >> /etc/sysctl.conf

# Optimize disk I/O
echo 'vm.dirty_ratio=15' >> /etc/sysctl.conf
echo 'vm.dirty_background_ratio=5' >> /etc/sysctl.conf
"

echo "4. Cleaning up..."
docker-compose -f docker-compose.ubuntu.yml exec lab-environment-ubuntu apt-get autoremove -y
docker-compose -f docker-compose.ubuntu.yml exec lab-environment-ubuntu apt-get clean

echo "Performance tuning completed"

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