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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:

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

This installs:

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

Verify the installation:

bash
docker version
docker compose version

Running Your First Container ​

Test that Docker works correctly:

bash
docker run --rm hello-world

Example: Running a Web Application ​

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

bash
# 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:

yaml
# 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: ${POSTGRES_PASSWORD}
    volumes:
      - pgdata:/var/lib/postgresql/data
    restart: unless-stopped

volumes:
  pgdata:

Note: Never hardcode database passwords in your compose files. Use a .env file in the same directory as your docker-compose.yml to define POSTGRES_PASSWORD and other secrets. Docker Compose automatically reads variables from .env.

Exposing Services Publicly ​

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

1. Cloudflare Tunnel (Recommended for quick testing) ​

bash
# 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:

yaml
# 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:

bash
docker stats

Set resource limits in your compose file:

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

Persistent Data ​

Always use Docker volumes for persistent data:

yaml
volumes:
  app_data:

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

Auto-restart ​

Ensure containers restart after instance reboot:

yaml
services:
  app:
    restart: unless-stopped

Logging ​

Configure logging to prevent disk space issues:

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

Troubleshooting ​

Docker daemon not starting ​

Check the Docker service status:

bash
systemctl status docker
journalctl -u docker

Permission denied errors ​

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

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

Out of disk space ​

Clean up unused resources:

bash
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
  • Credits - Understand how instances are paid for with credits
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