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Docker Tutorial — Part 8: Security & Best Practices

Docker makes deployment easy, but a careless Docker setup can become a security disaster. Security is not optional.

1. Never Run Containers as Root

By default, containers run as root. This is dangerous.

FROM node:18
RUN useradd -m appuser
USER appuser

2. Use Official & Minimal Images

• Prefer official images
• Use slim or alpine variants

FROM python:3.12-slim

3. Do Not Store Secrets in Images

Never hardcode passwords or API keys.

docker run -e DB_PASSWORD=secret myapp

4. Scan Images for Vulnerabilities

docker scan myimage

5. Limit Container Resources

docker run --memory=512m --cpus=1 myapp

Security Mindset

Containers reduce risk, but only if configured correctly. Security is a habit, not a feature.

Next, we connect Docker with real cloud and CI/CD workflows.