This demo replicates the Azure App Service deployment slot functionality using AWS Elastic Beanstalk to achieve zero-downtime deployments through blue-green deployment strategy.

🎯 What This Demo Does

This Terraform project creates:

• Blue Environment (Production) - Running Application v1.0

• Green Environment (Staging) - Running Application v2.0

• Complete infrastructure with load balancers, auto-scaling, and health checks

• Ability to instantly swap traffic between environments with zero downtime

🏗️ Architecture Overview

┌─────────────────────────────────────────────────────────────┐
│                  Elastic Beanstalk Application              │
├─────────────────────────────────────────────────────────────┤
│                                                             │
│  ┌──────────────────────┐      ┌──────────────────────┐   │
│  │  Blue Environment    │      │  Green Environment   │   │
│  │  (Production)        │      │  (Staging)           │   │
│  ├──────────────────────┤      ├──────────────────────┤   │
│  │  Version 1.0         │      │  Version 2.0         │   │
│  │  Load Balancer       │      │  Load Balancer       │   │
│  │  Auto Scaling        │      │  Auto Scaling        │   │
│  │  Health Checks       │      │  Health Checks       │   │
│  │                      │      │                      │   │
│  │  URL: my-app-blue... │      │  URL: my-app-green..│   │
│  └──────────────────────┘      └──────────────────────┘   │
│           │                              │                 │
│           └──────────────┬───────────────┘                 │
│                          │                                 │
│                 CNAME Swap (Instant)                       │
└─────────────────────────────────────────────────────────────┘

📋 Prerequisites

1. AWS Account with appropriate permissions

2. Terraform (>= 1.0) installed

3. AWS CLI configured with credentials

4. PowerShell (for packaging scripts)

5. Node.js (optional, for local testing)

Blue Environment (Production): http://my-app-bluegreen-blue-xxxxxx.elasticbeanstalk.com

Green Environment (Staging): http://my-app-bluegreen-green-xxxxxx.elasticbeanstalk.com

🔵 Testing the Blue Environment (Production - v1.0)

Visit the Blue environment URL. You should see:

• Version 1.0 displayed prominently

• Blue color scheme

• "PRODUCTION" badge

• Basic feature set

🟢 Testing the Green Environment (Staging - v2.0)

Visit the Green environment URL. You should see:

• Version 2.0 displayed prominently

• Green color scheme

• "STAGING" badge

• New features listed:

  • Refreshed UI with modern design

  • Improved performance

  • Enhanced security features

  • Better analytics tracking

  • Critical bug fixes

🔄 Performing the Blue-Green Swap

Once you've verified the Green environment is working correctly, perform the swap:

Option 1: Using the PowerShell Script (Recommended)

.\swap-environments.ps1

The script will:

1. Automatically read environment names from Terraform

2. Ask for confirmation

3. Perform the CNAME swap

4. Display status and next steps

Option 2: Using AWS CLI Directly

aws elasticbeanstalk swap-environment-cnames \
  --source-environment-name my-app-bluegreen-blue \
  --destination-environment-name my-app-bluegreen-green \
  --region us-east-1

Option 3: Using AWS Console (Step-by-Step with Screenshots)

Step 1: Open the AWS Console

• Navigate to AWS Elastic Beanstalk Console

• Ensure you're in the correct region (us-east-1 by default)

Step 2: Select Your Application

• In the Applications list, click on my-app-bluegreen

• You'll see both environments listed (Blue and Green)

Step 3: Choose an Environment to Swap

• Click on either the Blue or Green environment name

• (You can start from either environment - the result is the same)

Step 4: Access the Swap Action

• Click the Actions button (top right)

• From the dropdown menu, select Swap environment URLs

Step 5: Select the Target Environment

• A dialog will appear asking which environment to swap with

• Select the other environment from the dropdown

  • If you started from Blue, select Green

  • If you started from Green, select Blue

Step 6: Confirm the Swap

• Review the warning message about traffic redirection

• Click the Swap button to confirm

Step 7: Monitor the Swap

• The environments will show "Updating" status

• Wait 1-2 minutes for the swap to complete

• Both environments will return to "Ok" (green) status

Step 8: Verify Success

• Note that the URLs have been swapped

• The environment names stay the same, but the URLs are exchanged

• Visit both URLs to confirm the swap worked

✅ Verifying the Swap

After the swap completes (1-2 minutes), verify:

1. Blue URL now shows v2.0:

    Visit: <blue-url>
    Expected: "Welcome to Version 2.0 - Green Environment"
   

Green URL now shows v1.0:

Visit: <green-url>
Expected: "Welcome to Version 1.0 - Blue Environment"

1. Zero Downtime: Your production traffic seamlessly moved from v1.0 to v2.0!

🔙 Rolling Back

If you need to rollback to the previous version:

# Simply run the swap again!
.\swap-environments.ps1

The swap is instant and bidirectional - the previous production environment is still running the old version.

📊 Key Features Demonstrated

1. Zero-Downtime Deployment

• Traffic switches instantly at the DNS level

• No service interruption

• Users experience seamless transition

2. Easy Rollback

• Previous version still running in the other environment

• Instant rollback by swapping again

• No need to redeploy

3. Safe Testing

• Test new version in production-like environment

• Same infrastructure configuration

• Isolated from production traffic

4. Production Parity

• Both environments identical

• Same instance types, scaling, and configuration

• Eliminates "works on staging" issues

🏷️ Resource Tagging

All resources are tagged with:

• Project: BlueGreenDeployment

• Environment: Demo

• ManagedBy: Terraform

💰 Cost Considerations

This demo creates:

• 2 Application Load Balancers (~$16/month each)

• 2-4 EC2 instances (depending on auto-scaling)

• S3 bucket for application versions

• CloudWatch monitoring

Estimated Monthly Cost: $50-100 USD (depending on instance types and usage)

To minimize costs:

• Use t3.micro instances (default)

• Destroy resources when not in use: terraform destroy

• Set appropriate auto-scaling limits

🧹 Cleanup

To destroy all resources:

terraform destroy

Warning: This will delete:

• Both Elastic Beanstalk environments

• Application Load Balancers

• EC2 instances

• S3 bucket (if empty)

• All associated resources

🎓 What I Learned

✅ How to implement blue-green deployments on AWS
✅ Elastic Beanstalk environment management
✅ Zero-downtime deployment strategies
✅ Infrastructure as Code with Terraform
✅ AWS CLI for environment swapping
✅ Production-safe deployment practices

🎥 Day 17 Video ( link )

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🚀 Conclusion

This project provided deep hands-on experience with AWS elasticbeanstalk and Terraform.
I gained a stronger understanding of real-world cloud architecture challenges.

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🔖 Tags

#30DaysOfAWSTerraform #AWS #Terraform #elasticbeanstalk #blue&grean #DevOps #CloudComputing #IaC