In this post, you will learn how to create an AWS Application Load Balancer (ALB) for your EC2 instances running a Spring Boot application. You will also create an Autoscaling Group (ASG) which will simplify the setup and will automatically scale-in and scale-out.
A load balancer will make it possible to distribute the workload across multiple EC2 instances. A client application will connect to the load balancer without knowing which EC2 instance will handle the request. Because of this, EC2 instances can come and go without impacting your client requests. It is transparent because of the load balancer. It is easy to scale-out and thus to add more EC2 instances when traffic increases, or to scale-in and reduce the number of EC2 instances in order to reduce costs when traffic gets low.