Docker Exercises Plan

This document outlines the plan for creating a set of Docker exercises for beginners. The goal is to provide hands-on experience with containerizing a multi-service application.

Proposed Technology Stack

• Backend: A simple Node.js/Express "To-Do" list API.
• Frontend: A basic HTML/CSS/JavaScript application that interacts with the backend API.
• Database: A PostgreSQL database to store the to-do items.

Exercise Structure

The exercises will guide the student through containerizing and connecting the different parts of the application.

flowchart TD
    subgraph "Exercise Plan"
        direction LR
        E1["1 . Containerize the Backend"] --> E2["2 . Add a Database"];
        E2 --> E3["3 . Containerize the Frontend"];
        E3 --> E4["4 . Connect Everything with Docker Compose"];
    end

    subgraph "Application Components"
        Backend["Node.js API"]
        Frontend["HTML/JS App"]
        Database["PostgreSQL"]
    end

    E1 --> Backend;
    E2 --> Database;
    E3 --> Frontend;
    E4 --> Backend;
    E4 --> Frontend;
    E4 --> Database;

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Exercise Breakdown:

1. Backend First: Start with the Node.js backend. The student's first task will be to write a Dockerfile to containerize this application.
2. Adding the Database: Introduce the PostgreSQL database. The student will learn how to run a database as a container and connect the backend container to it. This will cover Docker networking basics.
3. Frontend Integration: Provide the frontend code. The student will write another Dockerfile to containerize the frontend application.
4. Orchestration with Docker Compose: Finally, the student will create a docker-compose.yml file to define and run the multi-container application (frontend, backend, database) with a single command.