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📊 Monitoring EC2 with CloudWatch and SNS Notifications​

📌 Objective​

In this tutorial, we will:

  • Launch an EC2 instance and host a Git-based website
  • Install the stress tool to simulate load
  • Connect the instance to CloudWatch
  • Set up a CloudWatch Alarm to detect CPU stress
  • Integrate SNS to send email notifications when stress is detected

🛠️ Prerequisites​

  • An AWS account with permissions for EC2, CloudWatch, and SNS
  • A GitHub repo (or any Git repo) with your website code
  • An email address to subscribe to SNS notifications

🧱 Step 1: Launch EC2 Instance and Set Up Git Website​

  1. Launch an EC2 instance:

    • AMI: Amazon Linux 2
    • Instance type: t2.micro (Free Tier eligible)
    • Networking: Enable Auto-assign Public IP
    • Security Group: Allow HTTP (port 80) and SSH (port 22)

  2. Connect to your instance via SSH:

    ssh -i "your-key.pem" ec2-user@<your-ec2-public-ip>

  3. Install Apache and Git:

    sudo yum update -y
    sudo yum install -y httpd git
    sudo systemctl start httpd
    sudo systemctl enable httpd

  4. Clone your GitHub repo into the web root:

    sudo git clone https://github.com/your-repo.git /var/www/html/

📍 Your website should now be live at:
http://<your-ec2-public-ip>

  1. Use the top command to monitor real-time system usage: 
    top

📬 Step 2: Create an SNS Topic and Subscribe​

  1. Open the Amazon SNS Console.

  2. Create a new topic:

    • Click Topics → Create topic
    • Type: Standard
    • Name: EC2-CPU-Alert
    • Click Create topic

  3. Add a subscription:

    • Protocol: Email
    • Endpoint: Your email address (e.g., you@example.com)
    • Click Create subscription

  4. Confirm your subscription:

    • Check your inbox and click the confirmation link from AWS.

📈 Step 3: Create CloudWatch Alarm for High CPU​

  1. Go to CloudWatch Console → Alarms → Create alarm

  2. Click Select metric →
    Browse to:
    EC2 > Per-Instance Metrics > CPUUtilization

  3. Choose your EC2 instance and configure the alarm:

    • Metric name: CPUUtilization
    • Period: 1 minute
    • Threshold: Greater than 60
    • Consecutive periods: 2

  4. Under Actions:

    • Select: Send a notification to your SNS topic

  5. Name the alarm: EC2-CPU-Alert

    • Click Create alarm

📷 Step 4: Check CloudWatch (Without Stress)​

  • Wait a few minutes after creating the alarm
  • Go to CloudWatch → Alarms
  • Status should be OK (green) — no CPU spike detected yet

💥 Step 5: Simulate CPU Stress​

  1. SSH into your EC2 instance again:

    sudo yum install -y stress
    stress --cpu 2 --timeout 120

  2. What happens:

    • After 1–2 minutes, the CPU load increases
    • CloudWatch detects the spike and changes the alarm state to ALARM (red)
    • You receive an email notification via SNS

  3. To stop the stress process:

    sudo pkill stress

    Or find and kill it manually:

    ps aux | grep stress
    sudo kill <PID>

  4. After stress is removed:

    • Go to CloudWatch → Alarms
    • Alarm status should return to OK (green)

✅ Conclusion​

In this tutorial, we demonstrated how to:

  • Monitor an EC2 instance using Amazon CloudWatch
  • Set up SNS to receive real-time email alerts
  • Simulate high CPU usage with the stress tool
  • Validate alarm triggers and notification delivery

By implementing this setup, you gain visibility into your instance performance and can react proactively to system stress — a key step in building reliable, production-grade infrastructure. 🚀