Docker for Beginners: From Zero to Running a Full Stack Locally in 10 Minutes

Source: Dev.to

Run any service instantly

docker run -d -p 8080:80 nginx:latest

Open after the command — you’ll see Nginx running. No install, no config, no conflicts.

Build your own app into an image

docker build -t my-app:1.0 .

Start your entire stack (app + db + cache)

docker compose up -d

Dockerfile for a Node.js app

FROM node:20-alpine
WORKDIR /app
COPY package*.json ./
RUN npm ci --only=production
COPY . .
EXPOSE 3000
CMD ["node", "server.js"]

Tip: Copying package*.json before the rest of the source lets Docker cache the npm ci step. After code changes, rebuilding takes a few seconds instead of tens.

Build and run

docker build -t my-app:1.0 .
docker run -d -p 3000:3000 my-app:1.0

Dockerfile for a Python/Flask app

FROM python:3.12-slim
WORKDIR /app
COPY requirements.txt .
RUN pip install --no-cache-dir -r requirements.txt
COPY . .
EXPOSE 5000
CMD ["python", "app.py"]

docker‑compose example (app + PostgreSQL + Redis)

version: "3.9"
services:
  app:
    build: .
    ports:
      - "3000:3000"
    environment:
      DATABASE_URL: postgres://user:pass@db:5432/mydb
      REDIS_URL: redis://cache:6379
    depends_on:
      - db
      - cache

  db:
    image: postgres:16-alpine
    environment:
      POSTGRES_USER: user
      POSTGRES_PASSWORD: pass
      POSTGRES_DB: mydb
    volumes:
      - pgdata:/var/lib/postgresql/data

  cache:
    image: redis:7-alpine

volumes:
  pgdata:

Typical workflow

docker compose up -d          # start everything
docker compose down           # stop everything
docker compose up -d --build  # rebuild after code changes
docker compose down -v        # stop + delete database data

The pgdata volume ensures the database persists across container restarts. Use -v only when you want a fresh start.

Common Docker commands

Best‑practice checklist

• ✅ Use Alpine or Slim base images (instead of the default ~1 GB images)
• ✅ Add a .dockerignore to exclude node_modules, .git, .env, etc.
• ✅ Run the container as a non‑root user (e.g., USER node)
• ✅ Pass secrets via environment variables, never hard‑code them
• ✅ Configure volumes for persistent data (e.g., database files)
• ✅ Add a health check, e.g.: HEALTHCHECK CMD curl -f http://localhost:3000/health || exit 1
• ✅ Verify the setup on a clean machine with docker compose up

Troubleshooting tips

• Container exits immediately – The app likely crashes on startup. Check logs with docker logs <container>. A common cause is a missing environment variable.
• Database is empty after restart – Ensure you have a volume defined for the database data; otherwise the data lives inside the container and is lost when it stops.
• Port already in use – Something else is bound to the host port. Stop that process or map a different host port, e.g., -p 3001:3000.
• Image is too large – Switch to a smaller base image (node:20-alpine), add a .dockerignore, and consider multi‑stage builds for compiled languages. Typical reduction: 1 GB → ~100 MB.

Further reading

The full guide covers installation walkthroughs for Windows/macOS/Linux, additional Python Dockerfile examples, Docker Desktop licensing (free vs. paid), multi‑stage builds, and a production‑readiness checklist.

Read the full article on trackstack.tech