CI/CD on AWS

What You'll Build

Automate deployments from GitHub to EC2 using AWS's CI/CD trio: CodePipeline, CodeBuild, and CodeDeploy — all configured through the AWS Console. Push code → tests run → app deploys automatically.

The Pipeline Flow

GitHub Push
    │
    ▼
┌─────────────────────────┐
│  Stage 1: SOURCE        │  CodeStar Connection detects push
│  (CodePipeline)         │  Downloads source code
└───────────┬─────────────┘
            ▼
┌─────────────────────────┐
│  Stage 2: BUILD         │  Uses buildspec.yml
│  (CodeBuild)            │  npm install → npm test → package
└───────────┬─────────────┘
            ▼
┌─────────────────────────┐
│  Stage 3: DEPLOY        │  Uses appspec.yml
│  (CodeDeploy)           │  Stop → Install → Start → Validate
└─────────────────────────┘

Required Files in Your Repo

Before creating the pipeline, your repository needs two config files that tell CodeBuild and CodeDeploy what to do:

buildspec.yml — Build Definition

Tells CodeBuild what to build. Like azure-pipelines.yml.

version: 0.2

phases:
  install:
    runtime-versions:
      nodejs: 18
    commands:
      - cd app && npm ci

  pre_build:
    commands:
      - cd app && npm test

  build:
    commands:
      - echo "Build succeeded on $(date)"

artifacts:
  files:
    - "**/*"
  discard-paths: no

appspec.yml — Deployment Definition

Tells CodeDeploy how to deploy. Defines lifecycle hooks for each stage.

version: 0.0
os: linux

files:
  - source: /
    destination: /home/ec2-user/sandbox-app/app

hooks:
  ApplicationStop:
    - location: scripts/stop_server.sh       # Stop old version
  BeforeInstall:
    - location: scripts/install_dependencies.sh  # Install Node.js
  AfterInstall:
    - location: scripts/after_install.sh     # npm install, run migrations
  ApplicationStart:
    - location: scripts/start_server.sh      # pm2 start
  ValidateService:
    - location: scripts/validate_service.sh  # curl /health

Step 1: Connect GitHub

Create a CodeStar Connection to let AWS access your GitHub repository. This is like creating a Service Connection in Azure DevOps.

Step 2: Create an Artifact Bucket

CodePipeline stores build artifacts (zipped source and compiled output) in S3 between pipeline stages.

Step 3: Create CodeBuild Project

CodeBuild is a managed build server that runs your buildspec.yml. It installs dependencies, runs tests, and packages artifacts.

Step 4: Create CodeDeploy Application

CodeDeploy deploys your built artifact to EC2 instances using the appspec.ymllifecycle hooks.

Deployment Strategies

Step 5: Create the Pipeline

CodePipeline ties everything together — it watches GitHub, triggers CodeBuild, and deploys via CodeDeploy.

🧪 Monitor & Test the Pipeline

After creating the pipeline, it runs automatically. Watch the progress:

1. Go to CodePipeline → select sandbox-pipeline📋
2. Watch 3 stages: Source → Build → Deploy
3. Click each stage for details (build logs, deployment progress)

Trigger a new deployment:

# Push any change to trigger the pipeline
echo "# Deploy test" >> README.md
git add . && git commit -m "test: trigger pipeline" && git push

The pipeline will detect the push, run CodeBuild (install, test, package), then deploy to your EC2 instances via CodeDeploy.

Key Takeaways

• CodePipeline orchestrates, CodeBuild builds, CodeDeploy deploys
• buildspec.yml = what to build, appspec.yml = how to deploy
• Lifecycle hooks give full control: stop → install → start → validate
• In-Place deployment for learning; Blue/Green for zero-downtime production
• The pipeline auto-triggers on every push to the configured branch