how to choose an auto scaling policy ?

Target Tracking Policy: This policy adjusts the capacity of the Auto Scaling group to maintain a specified target value for a specific metric. It continuously adjusts the group's capacity as the metric changes. While target tracking is useful for maintaining a specific level of utilization or performance,

Step Scaling Policy: Step scaling allows you to scale your Auto Scaling group based on a set of defined steps. Each step specifies the adjustment to make if the CloudWatch alarm for the associated metric is triggered. This policy is more suitable for scenarios where you can anticipate the scaling needs based on specific thresholds

Simple Scaling Policy: Simple scaling policies are based on a single scaling adjustment at a time, in response to a specific CloudWatch alarm

Given the sudden and unpredictable nature of the traffic increases in this scenario, the most suitable scaling policy would be the Step Scaling Policy.

Hi,

Did you try the EC2 AutoScaling Warm Pools to accelerate your auto-scaling ?

see https://aws.amazon.com/blogs/compute/scaling-your-applications-faster-with-ec2-auto-scaling-warm-pools/

Reference documentation: https://docs.aws.amazon.com/autoscaling/ec2/userguide/ec2-auto-scaling-warm-pools.html

Best

Didier