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Configuring Load Balancer For A Web Application.

INTRODUCTION: A load balancer takes requests from clients and distributes them across targets in a target group. Configuring load balancing for a web application involves distributing incoming network traffic across multiple servers to enhance performance, reliability, and availability.

PROBLEM STATEMENT: Configure a load balancer for a web application todistribute incoming traffic to enhance performance.


1]Configure a target group:

Configuring a target group allows you to register targets such as EC2 instances. The target group you configure in this step is used as the one in the listener rule when you configure your load balancer.

  • Open the Amazon EC2 console.
  • In the navigation pane, select “Target Groups.”
  • Click “Create target group.”
  • In the Basic configuration section:
    • Choose the target type (Instances or IP addresses).
    • Enter a name for the target group.
    • Modify the Port and Protocol as needed.
    • Select the IP address type (IPv4 or IPv6) if applicable.
      • Choose the desired VPC.
  • For Protocol version:
    • Select HTTP1 for HTTP/1.1 or HTTP/2 requests.
    • Select HTTP2 for HTTP/2 or gRPC requests.
    • Select gRPC for gRPC requests.
  • In the Health checks section:
    • Adjust health check settings, including the health check port, count, timeout, interval, and success codes.
    • Set the Unhealthy and Healthy threshold counts.
  • Click “Next.”

2] Register targets

You can register EC2 instances, IP addresses, or Lambda functions as targets in a target group. This is an optional step to create a load balancer. However, you must register your targets to ensure that your load balancer routes traffic to them.

  • In the “Register targets” page:
    • If the target type is “Instances,” select instances, enter ports, and choose “Include as pending.”
    • If the target type is “IP addresses”:
      • Select a network VPC or choose “Other private IP addresses.”
      • Enter IP addresses manually (up to five at a time) and specify ports.
      • Choose “Include as pending.”
      • If the target type is “Lambda,” select a Lambda function or enter its ARN, and choose “Include as pending.”
  • Click “Create target group.”

3] Configure a load balancer and a listener

To create an Application Load Balancer, you must first provide basic configuration information for your load balancer, such as a name, scheme, and IP address type. Then, you provide information about your network, and one or more listeners. A listener is a process that checks for connection requests. It is configured with a protocol and a port for connections from clients to the load balancer.

  • Open the Amazon EC2 console.
  • In the navigation pane, choose “Load Balancers.”
  • Choose “Create Load Balancer” and select “Create” under Application Load Balancer.
  • Basic Configuration:
    • Enter a unique name for the load balancer.
    • Choose either “Internet-facing” or “Internal” for the scheme.
    • Select “IPv4” or “Dualstack” for IP address type.
    • Choose the appropriate VPC and configure mappings.
  • Network Mapping:
    • Select subnets from two or more Availability Zones, one or more Local Zones, or one Outpost subnet.
    • Choose or create a security group for the load balancer.
  • Listeners and Routing:
    • Default listener accepts HTTP traffic on port 80.
    • Optionally, configure an HTTPS listener with security policy and SSL/TLS certificate settings.
  • Mutual Authentication (mTLS):
    • Optionally, enable mutual authentication and configure settings if needed.
  • Tag and Create:
    • Optionally, add tags to categorize your load balancer.
  • Review your configuration and choose “Create load balancer.”

4] Test the load balancer

After creating your load balancer, verify that your EC2 instances pass the initial health check. Check that the load balancer is sending traffic to your EC2 instance.

  • To test the load balancer:
  • After creating the load balancer, close the setup.
  • In the navigation pane, go to “Target Groups” and select the newly created target group.
  • Choose “Targets” to verify that instances are ready. Ensure at least one instance has a healthy status.
  • Go back to “Load Balancers” in the navigation pane and select the created load balancer.
  • Choose “Description” and copy the DNS name (e.g.,
  • For internet-facing load balancers, paste the DNS name into the address field of a web browser.
  • For internal load balancers, paste the DNS name into the address field of a web browser with private VPC connectivity.
  • If configured correctly, the browser should display the default page of your server.

CONCLUSION: In conclusion, the successful configuration of the Elastic Load Balancer (ELB) involves a systematic setup process, encompassing the creation of a load balancer, setting up target groups, and testing the load balancer’s functionality. By following the outlined steps, including defining basic configurations, managing network mapping, and ensuring proper security group settings, the ELB becomes a crucial component for distributing incoming traffic and enhancing the overall availability and reliability of applications. The ability to monitor target health, coupled with seamless DNS integration, provides a robust solution for efficiently managing and balancing workloads across instances.

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