Do you install runtimes (Node.js, Python, Ruby, etc.) and databases (PostgreSQL, MySQL) directly on the host OS every time you try a new programming language or framework? “OS environment contamination” that worries you about version conflicts and garbage files during uninstallation will become a thing of the past if you use Docker containers. We organize the steps to build a practical local development environment in a hands-on format.

Why can’t you install it directly into the host OS?

Version conflicts such as Project A requires Python 3.10 and Project B requires Python 3.12 are commonplace. Docker allows you to isolate your application execution environment and middleware as independent, disposable containers. Even when you get a new PC, you can instantly recreate a perfect development environment by cloning the repository and hitting a single command.

Practice: Minimum configuration of web application + DB compose.yaml

The following is an example of a standard compose.yaml that links a Node.js environment and a PostgreSQL database.

services:
  app:
    build: .
    ports:
      - "3000:3000"
    volumes:
      - .:/app
      - /app/node_modules
    environment:
      - DATABASE_URL=postgres://devuser:devpass@db:5432/devdb
    depends_on:
      - db

  db:
    image: postgres:16-alpine
    restart: always
    environment:
      POSTGRES_USER: devuser
      POSTGRES_PASSWORD: devpass
      POSTGRES_DB: devdb
    volumes:
      - db-data:/var/lib/postgresql/data
    ports:
      - "5432:5432"

volumes:
  db-data:

Two major tips for smooth development

1. Hot reload and volume mount: Bind mount the current directory (.:/app) into the container in order to immediately reflect changes in the source code on the host side. However, the key is to protect the node_modules and virtual environment inside the container with an anonymous volume so that they are not overwritten with empty folders on the host side.
2. Using VS Code Dev Containers: By combining the editor extension “Dev Containers”, you can start VS Code itself in a container and seamlessly use the container-side completion engine and linter with the same operational feel as the host.

Get a clean, reproducible development platform and focus on writing code.