How do I use Auto Scaling to improve the fault tolerance of an application behind my load balancer?

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Elastic Load Balancing (ELB) supports the following types of load balancers: Application Load Balancer, Network Load Balancer, and Classic Load Balancer. If you have a preexisting load balancer, then you can create an Auto Scaling group to automatically terminate unhealthy instances and launch new, healthy ones. This improves the fault tolerance of your application. You can also configure Auto Scaling to dynamically scale up your application in response to demand.

You can create an Auto Scaling group that launches copies of instances that you've already configured. You can also create a launch template that uses an Amazon Machine Image (AMI) instead. After you create the Auto Scaling group, attach your load balancer to it.

Note: You must create your Auto Scaling group in the same AWS Region and Availability Zone as your load balancer.

Related information

Tutorial: Set up a scaled and load-balanced application