AWS Elastic Load Balancers - Basic Configuration


AWS Elastic Load Balancers (ELB) distribute incoming application traffic across multiple Amazon Elastic Compute Cloud (EC2) instances. They play a critical role in ensuring high availability, fault tolerance, and scalability of your applications. In this guide, we will cover the basics of configuring an AWS Elastic Load Balancer.


Types of Elastic Load Balancers


AWS offers three types of Elastic Load Balancers:


  • Application Load Balancer (ALB): Best suited for routing HTTP/HTTPS traffic and is capable of content-based routing, SSL offloading, and more.
  • Network Load Balancer (NLB): Ideal for handling TCP/UDP traffic and provides ultra-low latency, making it suitable for high-performance applications.
  • Classic Load Balancer: The legacy option for simple load balancing needs and is still available but is recommended for most use cases.

Step 1: Create an Elastic Load Balancer


Here's how to create a basic Application Load Balancer (ALB) using the AWS Management Console:


  1. Log in to the AWS Management Console.
  2. Navigate to the EC2 service.
  3. In the "Load Balancers" section, click "Create Load Balancer."
  4. Choose "Application Load Balancer."
  5. Configure the load balancer with listeners, security groups, and subnets.
  6. Review and create the load balancer.

Step 2: Define Target Groups


Target groups are used to route traffic to specific sets of EC2 instances. You can create and configure target groups based on your application's requirements.


Step 3: Configure Routing Rules


Routing rules determine how traffic is distributed to target groups. ALBs allow for flexible content-based routing based on HTTP request attributes.


Step 4: Register EC2 Instances


After creating target groups, you need to register your EC2 instances with the target groups. This allows the load balancer to distribute traffic to the registered instances.


Step 5: Update DNS Records


Associate your domain with the Application Load Balancer's DNS name to direct traffic to the load balancer. This typically involves updating DNS records with your domain registrar.


Conclusion


Configuring an AWS Elastic Load Balancer is essential for ensuring the reliability and scalability of your applications. By following these basic steps, you can create an ALB and route traffic to your EC2 instances efficiently, providing a seamless user experience for your customers.