It is an web service that provides secure and resizable compute capacity on the cloud Can easily scale up/ down as per need
An instance is an virtual server for running applications on EC2. It can be taught of as an tiny part of a large computer. It has its own HDD, network, OS, etc. but it is all actually virtual
AMI (Amazon Machine Image) images that consist of preconfigured software/ application
Instance Types
Compute Optimized (Processing)
Memory Optimized (In-memory)
GPU Optimized
Storage Optimized
General Purpose (Hardware type of EC2)