private subnets in an Auto Scaling Group on aws?
There is a range of common scenarios when you want to use private subnets to be used in an auto scaling group:


Your traffic is terminated by reaches your infrastructure on a  Elastic Load Balancers and your web server instances are behind the load balancer. This reduces the attack surface of the web servers.


( I think I started to use "terminate" since seeing it being used for SSL/TLS termination, ie the server(s) that hold the secure certificates. But because you could also use a Network Load Balancer at the "edge" of your infrastructure, I see now its not appropriate to use in this context)


Your auto scaled resources are actually not responding to outside traffic, for example if they are worker resources processing messages from an SQS queue.


There was a similar mention of both "public and private subnets" all over my LinuxAcademy exam preparation, depending on your thinking processes it may be straightforward to just say: "autoscaling can use subnets", but then this may confuse other people.