Introduction to Amazon Elastic Load Balancing
Tags: loadbalancing, aws
Published: 2023-01-05 15:04:35

Author: Rajat Goel

Amazon Elastic Load Balancing (ELB) is a load balancing service provided by Amazon Web Services (AWS). It automatically distributes incoming application traffic across multiple targets, such as EC2 instances, containers, and IP addresses, in one or more Availability Zones. This allows you to increase the availability and fault tolerance of your application.

There are three types of load balancers in AWS: Application Load Balancer (ALB), Network Load Balancer (NLB), and Classic Load Balancer (CLB). ALB and NLB are both designed to handle modern, complex applications and provide high performance, while CLB is better suited for simple workloads. In this article, we will focus on ALB.

Application Load Balancer

ALB is a layer 7 load balancer that routes traffic based on the content of the request. It can handle HTTP and HTTPS traffic and provides advanced request routing, such as host-based routing, path-based routing, and support for multiple domains.

One of the key benefits of ALB is its ability to automatically scale to handle incoming traffic. When the number of requests increases, ALB can automatically add more capacity to handle the traffic. This helps to ensure that your application is always available and responsive, even during periods of high traffic.

Another benefit of ALB is its ability to automatically detect unhealthy targets and redirect traffic to healthy targets. This helps to ensure that your application remains available, even if one of your targets becomes unavailable.

In addition, ALB integrates with other AWS services, such as AWS WAF, which allows you to set up rules to block or allow traffic based on certain criteria, such as IP address, request headers, or the content of the request. This can help to protect your application from malicious traffic and improve the security of your application.

Setting up an Application Load Balancer

To set up an ALB, you first need to create a target group. A target group is a group of EC2 instances, containers, or IP addresses that you want to route traffic to. You can create a target group for each type of traffic that you want to route, such as web traffic or API traffic.

Next, you need to create a listener. A listener is a process that checks for connection requests from clients, such as a web browser. When a client connects to the load balancer, the listener forwards the request to the target group. You can create multiple listeners for different protocols, such as HTTP and HTTPS.

Finally, you need to create the load balancer itself. You can choose the type of load balancer that you want to create, such as an ALB or NLB, and specify the listeners and target groups that you want to use. You also need to specify the Availability Zones where you want to create the load balancer.

Once you have set up the load balancer, you can configure the routing rules to specify how traffic should be routed to the target group. For example, you can route traffic based on the host header or the path of the request.

Monitoring and Troubleshooting

AWS provides a number of tools to help you monitor and troubleshoot your load balancer. The AWS Management Console allows you to view the status of your load balancer, target groups, and targets. You can also use CloudWatch to monitor the performance of your load balancer and set up alerts for any issues.

If you encounter any problems with your load balancer, you can use the AWS Support Center to get help from AWS support staff. They can help you troubleshoot any issues and provide guidance on how to resolve them.