AWS Regional vs. Multi-AZ vs. Single-AZ

When I first started exploring about the AWS services, I came up with lot of services which are provided by AWS.
I thought it will be easy to remember the scope of each service initially but when I started digging more and more services, I ended up in confusion between regional, multi-AZ and single-AZ.
This is a small blog to remember which service has which sort of scope.
I hope it will help the readers to give clarity about the scope of the services and help them prepare of AWS Solution Architect Certification.

Elastic Load Balancer : Multi-AZ within a Region.

Elastic File System : Regional Service (Not tied to a particular region and it is accessible from all AZ’s within a region.

Elastic Block System : AZ specific (Tied to a specific AZ within a region)

Amazon Machine Image : Built Region Specific. (Can be copied across regions)

Auto Scaling Groups : Multi-AZ within a Region.

Learning While Choosing an OS for a Project:

Today, my team lead, who is a very skilled engineer, told us how Amazon's OS, Amazon Linux 2, can be troublesome when you use it for a project. He explained that Amazon Linux was initially developed by Amazon and thoroughly tested on features designed by Amazon engineers. However, after they launched Amazon Linux 2, they stopped providing updates for the original version of Amazon Linux.

Now, we want to install a specific Python version (3.10) on servers running Amazon Linux 2 to connect Ansible, which will ultimately be used by the Rundeck job for centralized automation. Unfortunately, this specific Python version is not supported by the OS.

His final advice was :

Always choose a Debian-based OS if you are using Linux.