Running Docker in Aleph Cloud Instances

Aleph Cloud instances support running Docker containers, allowing you to deploy containerized applications on decentralized infrastructure.

Prerequisites

• An Aleph Cloud instance (Ubuntu 22.04 recommended)
• SSH access to your instance
• Sufficient resources (recommended: 2+ vCPUs, 4GB+ RAM for typical Docker workloads)

Installing Docker

Connect to your instance via SSH and run the official Docker installation script:

curl -fsSL https://get.docker.com | sh

This installs:

• Docker Engine
• Docker CLI
• Docker Compose plugin
• containerd

Verify the installation:

docker version
docker compose version

Running Your First Container

Test that Docker works correctly:

docker run --rm hello-world

Example: Running a Web Application

Here's an example deploying a simple web service with Docker Compose:

# Create a project directory
mkdir ~/myapp && cd ~/myapp

# Create docker-compose.yml
cat > docker-compose.yml << 'EOF'
services:
  web:
    image: nginx:alpine
    ports:
      - "8080:80"
    volumes:
      - ./html:/usr/share/nginx/html:ro
    restart: unless-stopped
EOF

# Create a simple HTML page
mkdir html
echo '<h1>Hello from Aleph Cloud!</h1>' > html/index.html

# Start the service
docker compose up -d

# Check it's running
curl localhost:8080

Example: Running Multiple Services

Deploy a more complex stack with multiple containers:

# docker-compose.yml
services:
  app:
    image: python:3.11-slim
    command: python -m http.server 8000
    ports:
      - "8000:8000"
    restart: unless-stopped

  redis:
    image: redis:alpine
    restart: unless-stopped

  postgres:
    image: postgres:16-alpine
    environment:
      POSTGRES_PASSWORD: mysecretpassword
    volumes:
      - pgdata:/var/lib/postgresql/data
    restart: unless-stopped

volumes:
  pgdata:

Exposing Services Publicly

To make your containerized services accessible from the internet, you have several options:

1. Cloudflare Tunnel (Recommended for quick testing)

# Install cloudflared
curl -L https://github.com/cloudflare/cloudflared/releases/latest/download/cloudflared-linux-amd64 -o /usr/local/bin/cloudflared
chmod +x /usr/local/bin/cloudflared

# Create a quick tunnel
cloudflared tunnel --url http://localhost:8080

2. Port Forwarding via Aleph

Use the Aleph Cloud console or CLI to configure port forwarding for your instance.

3. Custom Domain with Reverse Proxy

Set up nginx or Caddy as a reverse proxy with SSL:

# docker-compose.yml with Caddy reverse proxy
services:
  caddy:
    image: caddy:alpine
    ports:
      - "80:80"
      - "443:443"
    volumes:
      - ./Caddyfile:/etc/caddy/Caddyfile
      - caddy_data:/data
    restart: unless-stopped

  app:
    image: your-app:latest
    expose:
      - "8000"

volumes:
  caddy_data:

Best Practices

Resource Management

Monitor container resource usage:

docker stats

Set resource limits in your compose file:

services:
  app:
    image: your-app
    deploy:
      resources:
        limits:
          cpus: '0.5'
          memory: 512M

Persistent Data

Always use Docker volumes for persistent data:

volumes:
  app_data:

services:
  db:
    image: postgres
    volumes:
      - app_data:/var/lib/postgresql/data

Auto-restart

Ensure containers restart after instance reboot:

services:
  app:
    restart: unless-stopped

Logging

Configure logging to prevent disk space issues:

services:
  app:
    logging:
      driver: "json-file"
      options:
        max-size: "10m"
        max-file: "3"

Troubleshooting

Docker daemon not starting

Check the Docker service status:

systemctl status docker
journalctl -u docker

Permission denied errors

If running as non-root, add your user to the docker group:

sudo usermod -aG docker $USER
# Log out and back in for changes to take effect

Out of disk space

Clean up unused resources:

docker system prune -a

Limitations

• Nested virtualization: Running VMs inside Docker containers may not work depending on the instance type
• Network performance: Container networking adds minimal overhead
• Disk space: Plan for container images and volumes in your instance storage allocation

Next Steps

• Custom Images - Create your own instance images
• Payment Models - Understand pay-as-you-go pricing