🛠️ Lab 5 — Auto-Scaling + Application Load Balancer

Type: Guided lab Time: ~90 minutes Difficulty: Intermediate Cost: ~$1 if cleaned up promptly. ⚠️ ALB costs $0.50/day — DELETE IT after the lab

🎯 What you’ll build

Build a load-balanced app that auto-scales from 2 → 6 EC2 servers when CPU spikes, then scales back down when traffic dies. The exact same pattern Netflix, Spotify, and your bank use.

📋 Prerequisites

  • Comfortable launching EC2 instances
  • Understanding of security groups
  • A clear schedule for cleanup — don’t start this lab if you can’t clean up the same day

🛠️ AWS Services used

  • EC2 Launch Templates — blueprint for new instances
  • Auto Scaling Group (ASG) — min 2 / desired 2 / max 6
  • Target Group — list of instances the ALB sends to
  • Application Load Balancer (ALB) — Layer 7 traffic distribution
  • CloudWatch — CPU metrics that trigger scaling

📖 The full walkthrough

Open Week3_Lab5_AutoScaling_ALB.html in your browser. It’s a complete step-by-step guide with screenshots, code snippets, and inline hints.

💡 The HTML file is self-contained — no install, no internet needed once you’ve cloned the repo. Just double-click to open in your browser.

🆘 If you get stuck

  1. Re-read the relevant step in the HTML walkthrough
  2. Check the Common Mistakes callouts (red boxes in the walkthrough)
  3. Expand the 💡 Hint sections for guidance
  4. WhatsApp the group with a screenshot of the error
  5. Tag your post with #week3done

🎓 Submission

  1. Screenshot of your ALB DNS name in the browser (refresh to see different instance IDs)
  2. Screenshot of the ASG Activity history showing BOTH a scale-out AND scale-in event
  3. Screenshot proving cleanup is complete (EC2 → Instances showing 0 running)

⬅️ Back to Week 3