Virtually every organization uses a directory service such as Active Directory to allow computers to join domains, list and authenticate users, and to locate and connect to printers, and other network services including SQL Server databases. A centralized directory reduces the amount of administrative work that must be done when an employee joins the organization, changes roles, or leaves.

With the advent of cloud-based services, an interesting challenge has arisen. By design, the directory is intended to be a central source of truth with regard to user identity. Administrators should not have to maintain one directory service for on-premises users and services, and a separate, parallel one for the cloud. Ideally, on-premises and cloud-based services could share and make use of a single, unified directory service.

Read more at – New AWS Directory Service