Highly configurable server

Instance Types

https://stackoverflow.com/a/56880093/13165967

AWS Solution Architect Associate Exam Study Notes: EC2 (Elastic Compute Cloud), and Lambda

M	General Purpose i.e. app server (default)	Web server, code repositories
T	Micro instances - Low cost, general purpose, web servers	Web server, code repositories
C	Compute, CPU/IOPS optimized, good for memory intensive compute	Gaming servers
D, I	Storage Optimized, sequential read and write access to very large data sets on local storage	NoSQL, in-memory
R, X, Z	Memory optimized	in-memory caches/databases, real time big data analytics
G, P, Inf	GPU	Machine Learning, computational finance, speech recognition
F	FPGA - Field Programmable Gate Array, for hardware acceleration of code	hardware acceleration code

Instance Sizes

Generally double in price and key attributes

For t2	vCPU	RAM (GB)
small	1	12
medium	2	24
large	2	36
xlarge	4	54

Instance Profile

Instead of embedding your Access Keys in your code so your Instance has permissions to access certain services, you can Attach an IAM Role to an instance.

An Instance Profile holds a reference to a Role

Placement Groups

Free
Optional

Let you to choose the logical placement of your instances to optimize for communication, performance or durability.

Cluster
- Packs instances close together inside an Availability Zone
- Low latency, node to node communication
- High Performance Computing — HPC
- Cannot be multi-AZ
Partition
- Spreads instances across logical partitions
- rack per partition, partitions do not share underlying hardware
- Large distributed and replicated workloads
Spread
- Each instance is placed on a different rack
- When critical instances should be keep separate from each other
- Can spread a max of 7 instances
- Can be multi-AZ