DevOps Day 20 – GitHub Actions Workflow with YAML (Modern CI/CD)

DevOps Day 20 – GitHub Actions Workflow with YAML (Modern CI/CD) 🚀

Welcome to Day 20 of the DevOps Series.

So far, we’ve explored CI/CD concepts and Jenkins pipelines.
Today, we move into modern CI/CD with GitHub Actions — a powerful, cloud-native automation tool built directly into GitHub.

GitHub Actions allows you to build, test, and deploy applications using YAML-based workflows, without managing any servers.

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🔍 What is GitHub Actions?

GitHub Actions is a CI/CD platform that automates workflows based on events in a GitHub repository.

These events can include:

• Code push

• Pull request

• Release creation

• Manual trigger

Everything is defined using YAML workflows, stored directly in your repo.

📁 Location:

.github/workflows/

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⚙️ Core Components of GitHub Actions

🔹 Workflow

A workflow is an automated process triggered by an event.

Defined as a .yml file inside .github/workflows/.

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🔹 Events

Events decide when the workflow runs.

Common events:

• push

• pull_request

• workflow_dispatch (manual trigger)

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🔹 Jobs

A workflow contains one or more jobs.

Each job:

• Runs on a virtual machine (runner)

• Executes steps sequentially

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🔹 Runners

Runners are the machines that execute workflows.

Examples:

• ubuntu-latest

• windows-latest

• macos-latest

GitHub automatically spins them up and shuts them down — zero infrastructure management.

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🔹 Steps

Steps are individual tasks inside a job.

Examples:

• Checkout code

• Install dependencies

• Run tests

• Build application

• Deploy

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📄 Basic GitHub Actions Workflow Example

name: CI Pipeline

on:
  push:
    branches: [ main ]

jobs:
  build:
    runs-on: ubuntu-latest

    steps:
    - name: Checkout Code
      uses: actions/checkout@v4

    - name: Run Build
      run: echo "Building the application"

    - name: Run Tests
      run: echo "Running tests"

This workflow:

• Triggers on every push to main

• Runs on Ubuntu

• Builds and tests the application

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🚀 CI/CD Flow with GitHub Actions

1️⃣ Developer pushes code to GitHub
2️⃣ GitHub event triggers workflow
3️⃣ Runner spins up automatically
4️⃣ Build, test, and deploy steps execute
5️⃣ Runner shuts down after completion

💡 No idle servers. No Jenkins maintenance.

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🔁 GitHub Actions vs Jenkins

Feature	GitHub Actions	Jenkins
Setup	Zero setup	Manual installation
Infrastructure	Managed by GitHub	Self-managed
Scalability	Auto-scale	Manual scaling
Cost	Pay-per-use	Always-on servers
Configuration	YAML	Groovy + UI

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🌍 Real-World Use Cases

✅ CI Pipeline

• Run unit tests

• Static code analysis

• Generate reports

✅ CD Pipeline

• Deploy to cloud (AWS, Azure, GCP)

• Deploy to Kubernetes

• Publish Docker images

✅ Open Source Projects

• PR validation

• Security scans

• Automated releases

✅ Microservices

• Independent workflows per service

• Event-driven pipelines

• Faster feedback loops

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🔐 Secrets & Environment Variables

Sensitive data like tokens and passwords are stored securely using GitHub Secrets.

Example:

env:
  AWS_ACCESS_KEY: ${{ secrets.AWS_ACCESS_KEY }}

Secrets are:

• Encrypted

• Masked in logs

• Scoped per repository or environment

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🧠 DevOps Best Practice

✔ Keep workflows small and modular
✔ Use reusable workflows
✔ Fail fast using test stages
✔ Use caching for faster builds
✔ Secure secrets properly

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✅ Summary

In Day 20, we learned:

• What GitHub Actions is

• Workflow structure using YAML

• Jobs, runners, and steps

• CI/CD automation with zero infrastructure

• Why GitHub Actions is ideal for modern DevOps

GitHub Actions represents the future of CI/CD — fast, scalable, and deeply integrated with source control.