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Everything You Need to Know About Application Load Balancer

The requirement for load balancing has grown more crucial than ever in today’s world as organizations are shifting to cloud computing. By dividing network traffic among several servers, a procedure known as load balancing makes sure that no one server is overloaded. In this article, you will learn everything you need to know about Application Load Balancer (ALB), a feature of Elastic Load Balancing (ELB) in Amazon Web Services (AWS).

What is an Application Load Balancer?

An Elastic Load Balancing tool called an Application Load Balancer allows developers to set up and automate incoming end-user traffic to applications running on the AWS public cloud. It acts as the client’s single point of contact and splits up incoming application traffic among numerous targets, like EC2 instances spread across numerous Availability Zones. By doing this, you can make your application more accessible and make sure it can process plenty of requests.

Components of an Application Load Balancer

The components of an application load balancer are as follows:

  • Load Balancer: The load balancer acts as the gateway for incoming traffic and splits it up among various targets.
  • Target Group: A target group is a collection of targets that the load balancer sends traffic to, such as EC2 instances.
  • Listener: The load balancer receives connection requests from clients and monitors them for possible connections.
  • Rules: Based on the request’s content, rules are used to direct traffic to various target groups.
  • Health Check: A health check is a process for evaluating the targets within a target group and removing any unhealthy targets.

Content-Based Routing

Content-based routing is one of the main characteristics of an application load balancer. By using content-based routing, you can direct traffic to various target groups according to the request’s content. For instance, you can direct traffic to various target groups based on the request’s host header or URL path. This makes it possible to design more intricate routing rules and guarantees that your application can manage a high volume of requests.

Load Balancing Algorithms

To distribute traffic among numerous targets, an application load balancer employs load balancing algorithms. Static load balancing algorithms and dynamic load balancing algorithms are the two types.

Static load balancing algorithms divide tasks without considering the current status of the system. A static load balancer won’t be able to identify which servers are running slowly or aren’t getting enough use. Rather, it distributes tasks in accordance with a predetermined strategy. It takes little time to set up static load balancing, but it might not be the best solution for applications that need high availability.

On the other hand, dynamic load balancing algorithms alter the task distribution in accordance with the system’s present state. Although being more complicated than static load balancing algorithms, dynamic load balancing algorithms offer better performance and greater availability.


To sum up, an Application Load Balancer is an attribute of Elastic Load Balancing that helps you to spread out incoming application traffic among numerous targets, such as EC2 instances, in numerous Availability Zones. It makes your application more accessible and guarantees that it can manage a huge number of requests. An application load balancer is a potent tool for controlling the traffic to your application with content-based routing and load balancing algorithms.

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