Auto Scaling helps you maintain application availability and allows you to dynamically scale your Amazon EC2 capacity up or down automatically according to conditions you define.
You can use Auto Scaling for Fleet Management of EC2 instances to help maintain the health and availability of your fleet and ensure that you are running your desired number of Amazon EC2 instances.
You can also use Auto Scaling for Dynamic Scaling of EC2 instances in order to automatically increase the number of Amazon EC2 instances during demand spikes to maintain performance and decrease capacity during lulls to reduce costs.
Auto Scaling is well suited both to applications that have stable demand patterns or that experience hourly, daily, or weekly variability in usage.
Beyond Auto Scaling for Amazon EC2, you can use Application Auto Scaling to automatically scale resources for other AWS services, including Amazon ECS, Amazon EC2 Spot Fleets, Amazon EMR Clusters, AppStream 2.0 fleets, and Amazon DynamoDB.