Building Microservices with Docker

Overview

This lesson covers the fundamentals of building microservices using Docker as a containerization platform. We will explore key concepts, setup instructions, and best practices.

What are Microservices?

Microservices are an architectural style that structures an application as a collection of loosely coupled services. Each service is designed to perform a specific business function.

Introduction to Docker

Docker is a platform that enables developers to automate the deployment of applications inside lightweight, portable containers. It allows you to package your application and its dependencies into a container that can run consistently across different environments.

Setting Up Docker

1. Install Docker on your machine. Follow the instructions on the official Docker installation guide.
2. Verify the installation by running:

docker --version

3. Run the Docker Hello World image to ensure it's working:

docker run hello-world

Building a Microservice

Step 1: Create a Simple Node.js Microservice

const express = require('express');
const app = express();
const PORT = process.env.PORT || 3000;

app.get('/', (req, res) => {
    res.send('Hello, Microservices!');
});

app.listen(PORT, () => {
    console.log(`Server is running on port ${PORT}`);
});

Step 2: Create a Dockerfile

FROM node:14

WORKDIR /app
COPY package*.json ./
RUN npm install
COPY . .

EXPOSE 3000
CMD ["node", "index.js"]

Step 3: Build and Run the Docker Container

1. Build the Docker image:

docker build -t my-microservice .

2. Run the Docker container:

docker run -p 3000:3000 my-microservice

Best Practices

• Keep services small and focused.
• Use API gateways for service communication.
• Implement logging and monitoring.
• Use container orchestration tools like Kubernetes for managing multiple containers.

FAQ