Project: Containerize a Simple Application

Practical project to containerize a simple web application using Docker.

By Kevin McAleer,    3 Minutes

Project Overview

This practical project is designed to give you hands-on experience with Docker. You will containerize a simple web application, learning the entire process from creating a Dockerfile to running the application in a container. This exercise will solidify your understanding of Docker and its application in real-world scenarios.

Step-by-Step Guide

Application Overview

  • Web Application: For this project, consider a basic web application, such as a simple Python Flask or Node.js app.
  • The application should have a basic functionality, like displaying a static page or returning a response to a web request.

Creating a Dockerfile

  1. Dockerfile Basics:
    • Start with specifying the base image, like python:3.8 or node:14.
    • Set a working directory in the container, e.g., WORKDIR /app.
  2. Adding Application Files:
    • Use the COPY command to copy your application files into the container.
  3. Installing Dependencies:
    • For Python, copy the requirements.txt file and run pip install.
    • For Node.js, copy the package.json file and run npm install.
  4. Setting the Run Command:
    • Use the CMD command to set the command that runs your application, such as python or npm start.

Building the Image

  • Run docker build -t myapp:latest . to build the Docker image from your Dockerfile.
  • The -t flag tags your image, and . indicates the current directory as the build context.

Running the Container

  • Once the image is built, run it with docker run -p 5000:5000 myapp:latest.
  • The -p flag maps a port on your host to a port in the container.

Testing and Deployment

Testing Your Container

  • Local Testing: Access your application by navigating to http://localhost:5000 in your web browser.
  • Ensure all functionalities work as expected in the containerized environment.

Tips for Deployment

  • Container Registry: Consider pushing your image to a container registry like Docker Hub for easy deployment.
  • Environment Variables: Use environment variables for configuration settings that change between environments.
  • Logging and Monitoring: Implement logging and monitoring for your containerized application to ensure its health and performance in production.

By completing this project, you will have gained valuable experience in containerizing applications with Docker. This foundational skill is crucial for modern software development and deployment practices.

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