Example

Real-Time Example of Elastic Load Balancer (ELB)

Scenario: E-Commerce Website Handling High Traffic

Imagine you are managing an e-commerce platform (e.g., Amazon, Flipkart) where thousands of users visit the website daily. During sales events like Black Friday or Diwali Sales, traffic spikes significantly. To ensure high availability, fault tolerance, and load distribution, you set up an Elastic Load Balancer (ELB).

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Solution: Implementing ELB in AWS

Your e-commerce platform runs on an Auto Scaling Group of EC2 instances deployed in multiple availability zones (AZs). You place an Application Load Balancer (ALB) in front of your EC2 instances to distribute incoming traffic efficiently.

Step-by-Step Setup:

1. Create an Application Load Balancer (ALB)

   • Choose internet-facing or internal based on requirements.

   • Deploy across multiple Availability Zones (e.g., us-east-1a, us-east-1b).

   • Assign a public IP and domain (e.g., www.mystore.com).

2. Register EC2 Instances with Target Group

   • Add instances from the Auto Scaling Group.

   • Define a Health Check (e.g., HTTP:80 on /health endpoint).

3. Set Up Listener Rules

   • Traffic on port 80 (HTTP) gets forwarded to the web servers.

   • SSL/TLS termination can be configured for HTTPS (port 443).

4. Test the Load Balancer

   • Access the ALB DNS Name (http://mystore-alb-123456.us-east-1.elb.amazonaws.com).

   • If traffic is high, ALB automatically distributes requests.

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Real-Time Benefits of ELB in E-Commerce

✅ Handles High Traffic Spikes – Ensures smooth performance during peak shopping events. ✅ Fault Tolerance & High Availability – Even if one EC2 instance fails, traffic is redirected to healthy instances. ✅ SSL Termination & Security – Protects customer data using HTTPS encryption. ✅ Auto Scaling Integration – Automatically adds/removes EC2 instances based on demand.

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Example Flow in Action:

1. A customer visits www.mystore.com to purchase a phone.

2. ALB routes the request to one of the healthy EC2 instances running the application.

3. If traffic increases, Auto Scaling Group launches more instances, and ELB distributes load automatically.

4. If an instance fails, ELB reroutes traffic to other healthy instances.

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Common Issues and Fixes

Issue	Cause	Fix
503 Service Unavailable	No healthy EC2 instances	Check target group health checks
High Latency	Overloaded instances	Increase instance size or add more instances
SSL Certificate Issue	Expired/misconfigured SSL	Update SSL certificate in ACM

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Final Thoughts

Elastic Load Balancer (ELB) ensures scalability, reliability, and high availability for modern applications. Whether it's an e-commerce website, video streaming platform (Netflix), or banking app, ELB plays a crucial role in handling real-time traffic efficiently. 🚀

Would you like an example with AWS CLI/Terraform configuration?