Day 2 of My Devops Journey: Automating Dockerized Application Deployment with GitHub Actions

#githubactions #devops #docker #beginners

Introduction:

Welcome back to Day 2 of my 90-day DevOps journey! Inspired by my experience in the @SheCodeAfrica mentorship program, today we'll dive into automating the deployment of a Dockerized web application using GitHub Actions. This guide aims to simplify CI/CD processes, making application deployments more efficient and reliable.

What You'll Learn:

Building a Dockerized Node.js application.
Setting up GitHub Actions for automating Docker image builds and deployments.
Overcoming challenges encountered during setup.

Prerequisites:

Before we begin, ensure you have:

Basic understanding of Docker and GitHub (refer to my previous articles if needed).
A GitHub account for repository hosting.
Docker installed on your local machine for testing.

Step-by-Step Guide: Automating Dockerized Application Deployment with GitHub Actions

Step 1: Prepare Your Dockerized Application

Create Your Application:
- Start by creating a simple Node.js application. Navigate to your terminal and execute:
```
 mkdir my-docker-app
 cd my-docker-app
```
Initialize Git Repository:
- Initialize Git for version control:
```
 git init
```

Write Your Application Code:

Create a basic Node.js application. For example, create an app.js file:

app.js:

 const http = require('http');

 const hostname = '0.0.0.0';
 const port = 3000;

 const server = http.createServer((req, res) => {
   res.statusCode = 200;
   res.setHeader('Content-Type', 'text/plain');
   res.end('Hello, World!\n');
 });

 server.listen(port, hostname, () => {
   console.log(`Server running at http://${hostname}:${port}/`);
 });

Create a Dockerfile:

Define a Dockerfile in the project root:

Dockerfile:

 FROM node:14

 WORKDIR /app

 COPY package*.json ./
 RUN npm install

 COPY . .

 EXPOSE 3000

 CMD ["node", "app.js"]

Test Locally:

Build and run your Docker container locally:

 docker build -t my-docker-app .
 docker run -p 3000:3000 my-docker-app

Open http://localhost:3000 in your browser to verify the application works.

Step 2: Set Up GitHub Repository

Create a GitHub Repository:
- Visit GitHub and create a new repository (my-docker-app).

Push Your Code:

Push your local Git repository to GitHub:

 git remote add origin <repository-url>
 git add .
 git commit -m "Initial commit"
 git branch -M main
 git push -u origin main

Step 3: Configure GitHub Actions Workflow

Create a Workflow File:

Inside .github/workflows, create docker-build-deploy.yml:

docker-build-deploy.yml:

 name: Docker Build & Deploy

 on:
   push:
     branches:
       - main

 jobs:
   build-and-deploy:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout Repository
         uses: actions/checkout@v2

       - name: Login to Docker Hub
         uses: docker/login-action@v2
         with:
           username: ${{ secrets.DOCKER_USERNAME }}
           password: ${{ secrets.DOCKER_PASSWORD }}

       - name: Build and Push Docker Image
         run: |
           docker build -t ${{ secrets.DOCKER_USERNAME }}/my-docker-app:latest .
           docker push ${{ secrets.DOCKER_USERNAME }}/my-docker-app:latest

       - name: Deploy Docker Container
         run: |
           docker run -d -p 80:3000 --name my-docker-app ${{ secrets.DOCKER_USERNAME }}/my-docker-app:latest

Add GitHub Secrets:
- Go to your GitHub repository > Settings > Secrets.
- Add Docker Hub credentials (DOCKER_USERNAME and DOCKER_PASSWORD).

Challenges Faced and Solutions:

Port Already Allocated: During testing, encountering a "port already allocated" error due to a previous Docker container using the same port. This was resolved by stopping the previous container (docker stop <container-id>) or specifying a different port during container deployment.

Recommended Resources for Beginners:

Docker Basics: Get Started with Docker
GitHub Actions: Explore GitHub Actions Documentation

Conclusion:

Congratulations on completing Day 2 of our DevOps journey! You've automated Dockerized application deployment with GitHub Actions, improving your CI/CD pipeline skills. Stay tuned for more articles as we explore some more.

See you on Day 3!