When scaling applications in the cloud, load balancing is an important component to ensure reliability and performance. AWS provides a great solution with its Elastic Load Balancer (ELB) service, allowing you to distribute incoming traffic across multiple EC2 instances.

Step 1: Launch EC2 Instances

First, you need to launch the EC2 instances that will serve as your application servers.

• Log in to the AWS Management Console.
• Navigate to EC2 > Instances and click Launch Instance.
• Choose an Amazon Machine Image (AMI), such as Amazon Linux 2.
• Select an instance type (e.g., t2.micro for free-tier).
• Configure the instance details, such as network and storage.
• Under Security Groups, allow HTTP (port 80).
• Review and launch the instance.

Repeat this process to launch additional instances as needed.

Step 2: Create a Target Group

A target group is used to route requests to one or more registered targets (EC2 instances).

• Navigate to the EC2 Dashboard and select Target Groups under the Load Balancing section.
• Click Create Target Group.
• Choose Instances as the target type.
• Give your target group a name and select the appropriate VPC.
• Set the health check settings, such as protocol and path (e.g., HTTP and /).
• After creation, register your EC2 instances with the target group by selecting them and clicking Include as pending below.

Step 3: Create and Configure the Load Balancer

Now that you have your target group set up, you need to create a load balancer to distribute traffic across your instances.

• Navigate to the Load Balancers section and click Create Load Balancer.
• Choose the load balancer type (for example, Application Load Balancer).
• Give your load balancer a name and select the appropriate scheme (internet-facing or internal).
• Configure the network mapping by selecting the VPC and availability zones.
• Set up the security groups to allow inbound HTTP traffic.
• Under Listeners and Routing, associate the load balancer with the target group you created earlier.
• Review and create the load balancer.

Step 4: Test the Load Balancer

Once your load balancer is up and running, you can test it:

• Navigate to the Load Balancers section and find the DNS name of your load balancer.
• Paste the DNS name into your browser to see your application served by the EC2 instances behind the load balancer.

The load balancer will distribute incoming traffic across the registered EC2 instances in the target group, ensuring high availability and reliability.