The App Server Auto Scaling is used when the number of web servers for delivering an application is to be kept flexible.
The App Server Single is usually used as a web-, backend- or cron-server. In contrast to App Server Auto Scaling it is always based .
The Container Cluster ECS is a fully managed container environment. With that component you can use container in business critical environments without stress: You deliver the containers, we take care of everything else.
AWS Lambda lets you run code without provisioning or managing servers. You pay only for the compute time you consume. Lambda runs your code on high-availability compute infrastructure.