Application Auto Scaling

Application Auto Scaling extends auto scaling to cover multiple services. They use CloudWatch alarms to determine when to scale out or back in.

Concepts

• Scaling Plans define a set of resources and a strategy for scaling them in and out.
• Scaling Policies define scaling strategies.

Supported services

• ECS clusters
• EC2 Spot Fleets
• EMR
• AppStream 2.0
• DynamoDB
• Aurora replicas
• SageMaker
• Custom resources

Finding scalable resources

Resources which support scaling policies can be identified through a range of means:

• CloudFormation stack.
• Tags, though this doesn't currently work for EC2 Spot Fleets.
• EC2 Auto Scaling Groups.

Scaling policies

Multiple scaling policies are supported.

Target tracking

In this configuration, resources are scaled based on a target value for a CloudWatch metric.

Step-based

Step scaling allows resources to be scaled proportionally to a breach of a CloudWatch alarm.

Scheduled

Scheduled scaling policies allow scaling based on the date and time, and can be useful for fairly predictable workloads where demand is understood.