An environment has an Auto Scaling group across two Availability Zones referred to as AZ-a and AZ-b and a default termination policy. AZ-a has four AmazonEC2 instances, and AZ-b has three EC2 instances. None of the instances is protected from a scale-in.How will Auto Scaling proceed if there is a scale-in event?
For Auto Scaling Groups with Multiple Instance Types and Purchase Options, the scale-in action respects the On-Demand base amount and the percentages set for On-Demand and Spot Instances. When the group scales in, the Auto Scaling group first identifies which of these two types of instances it will terminate. Then, it chooses the Availability Zone with the most instances of that type, and applies the default or customized termination policy.https://docs.aws.amazon.com/autoscaling/ec2/userguide/as-instance-termination.html