Related: Active Directory


Some services require Directory Service, like Amazon Workspaces

Run in VPC, to implement High availability (HA), deploy multiple AZs
Can be Isolated (Like being AWS only) or integrated or act as a proxy in connector mode.

Simple AD Mode

Uses open-source Samba (software) - Wikipedia ver. 4 directory service.
Simple iD is a default go-to.
If you want to migrate people to AWS Managed Microsoft AD there you go: Migrate users from Active Directory to AWS Managed Microsoft AD - AWS Directory Service

AWS Managed Microsoft AD

Literally AD in AWS, which can be independent from on-premise service,

AD Connector

Just connects AWS Services to on-premise AD