When a AWS Auto Scaling Group is scaling out which ec2 instance is considered to be Primary

Question

When a AWS Auto Scaling Group is scaling out which ec2 instance is considered to be Primary?

Meaning if my ASG is scaling out which ec2 instance ASG considers as a base instance?

Because if I am making changes in the First ec2 instance I created those are not transfered to other new ec2 instance created by ASG

Answer 1

Data is not automatically copied from existing instances to new instances. You can use lifecycle hooks to copy the data or an Amazon RDS database including replicas.

https://docs.aws.amazon.com/autoscaling/ec2/userguide/lifecycle-hooks.html