2th of 3 Questions.
What is an AMI?
Introduction to Amazon Machine Images
An Amazon Machine Image (AMI) is a supported and maintained image provided by AWS that provides the information required to launch an instance. It serves as a master template for the root volume of the instance, containing the operating system, an application server, and applications.
Components of an AMI
A template for the root volume for the instance (e.g., OS, application server).
Launch permissions that control which AWS accounts can use the AMI to launch instances.
A block device mapping that specifies the volumes to attach to the instance when it's launched.