☁Setting up an Application Load Balancer with AWS EC2.

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🔹 What is Load Balancing? 🤔

Load balancing is the process of distributing incoming traffic across multiple servers to:

• Prevent overloading any single server

• Improve application performance

• Increase fault tolerance

AWS Elastic Load Balancing (ELB)

AWS provides Elastic Load Balancing (ELB) to automatically distribute traffic across multiple EC2 instances. There are three types:

• Application Load Balancer (ALB) - Operates at Layer 7 (Application Layer) and is ideal for advanced routing and microservices.

• Network Load Balancer (NLB) - Operates at Layer 4 (Transport Layer) and is optimized for high throughput and low latency.

• Classic Load Balancer (CLB) - Operates at Layer 4, used for basic load balancing needs.

Today, we will set up an Application Load Balancer (ALB)! 🚀

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🏗️ How Does ALB Work?

An Application Load Balancer (ALB) consists of:

• Listeners: Monitor incoming requests and apply routing rules.

• Target Groups: Group EC2 instances or AWS services for traffic distribution.

• Health Checks: Continuously monitor the availability of target instances.

• Rules & Conditions: Define how requests should be routed (e.g., based on path, host, or headers).

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🎯 Today's Tasks:

Task 1: Launch EC2 Instances & Install Apache 🖥️

1. Launch two EC2 instances using an Ubuntu AMI.

2. Use User Data to install the Apache Web Server on both instances:

    #!/bin/bash
    apt update -y
    apt install apache2 -y
    echo "<h1>YourName's Web Server</h1>" > /var/www/html/index.html
    systemctl restart apache2
   

3. Modify the index.html file for the second instance:

    echo "<h1>TrainWithShubham Community is Super Awesome :)</h1>" > /var/www/html/index.html
   

4. Copy the public IP addresses of both instances.

5. Open a web browser and visit http://<instance_public_ip>.

6. You should see the respective webpages! 🎉

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Task 2: Set Up an Application Load Balancer (ALB) 🏗️

1. Navigate to AWS EC2 Console and select Load Balancers.

2. Click Create Load Balancer → Select Application Load Balancer.

3. Configure ALB:

   • Name: My-ALB

   • Scheme: Internet-facing

   • Listener: HTTP (Port 80)

   • VPC: Select your default or existing VPC

   • Availability Zones: Select at least two AZs

4. Create a Target Group:

   • Name: My-Target-Group

   • Target Type: Instance

   • Protocol: HTTP

   • Port: 80

5. Register Targets:

   • Select the two EC2 instances from Task 1

   • Click Include as pending below → Register Targets

6. Review & Create the ALB.

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✅ Testing ALB

• Open EC2 → Load Balancers → Copy the DNS Name of your ALB.

• Paste the DNS in a web browser (http://<ALB_DNS>).

• Refresh multiple times to see requests being routed between the two EC2 instances!

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🎉 Conclusion

Congratulations! 🥳 You've successfully:

✔️ Launched two EC2 instances with Apache

✔️ Created an Application Load Balancer

✔️ Distributed traffic between instances

This setup ensures scalability, fault tolerance, and high availability for your application. Keep exploring AWS, and happy cloud computing! 🚀

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