Docker – Configuration

Docker configuration allows you to customize container behavior, environment variables, and services. Proper configuration ensures that containers run consistently across different environments and meet application requirements.

Environment Variables

Environment variables provide configuration options to containers without modifying the image.


# Pass environment variables during container run
docker run -d -e MYSQL_ROOT_PASSWORD=rootpassword mysql:5.7

# Or using a file
docker run --env-file ./env.list mysql:5.7

Using Docker Configuration Files

You can use configuration files like docker-compose.yml or Dockerfile to define services, networks, volumes, and other container options.


# Example Dockerfile configuration
FROM node:18
WORKDIR /app
COPY package*.json ./
RUN npm install
COPY . .
EXPOSE 3000
CMD ["node", "index.js"]

Configuring Services with Docker Compose


version: '3'
services:
  web:
    image: my-node-app
    ports:
      - "3000:3000"
    environment:
      NODE_ENV: production
    volumes:
      - ./app:/app

Best Practices for Docker Configuration

Use environment variables for sensitive data and configuration.
Keep Dockerfiles and Compose files version-controlled.
Separate configuration from code for flexibility.
Document all configuration options for team clarity.
Use default values and fallback mechanisms to prevent failures.

Conclusion

Proper Docker configuration ensures consistent, secure, and scalable container deployments. By managing environment variables, files, and services, you can streamline container orchestration and maintain reliable applications.