Provisioning administrative accounts in AWS – account linking
Account linking is when a service provider correlates a locally managed account with the subject of an external IDP's federated token. The local account may get created in a just-in-time fashion from the information contained within the IDP's authentication token, or the account may have been created earlier and was correlated by matching on a unique identifier, such as an email address. Arguably, when both AWS SSO and the IDP use Active Directory as their account stores, but the IDP itself does not manage the accounts, this is also an example of account linking. Though all the data ultimately stems from the same Active Directory instance, there is no explicit link between the account, as presented by the IDP, and the account stored within the AWS user store.
However, our example company is not using Active Directory. As such, we need to manually create some matching user records inside AWS SSO for our...