@Jay Bloodworth Welcome to Microsoft Q&A Forum, Thank you for posting your query here!
It sounds like you're on the right track with setting up your ANF account and understanding the Active Directory (AD) connection. Let's address your questions one by one:
Why is this done with a username and password instead of a service principal?
- The Azure NetApp Files (ANF) AD connection admin account must be an AD DS domain user account in the same domain where the Azure NetApp Files computer accounts are created. This account must have the permission to create computer accounts (for example, AD domain join) in the AD DS organizational unit path specified in the Organizational unit path option of the AD connection[1]. This is why a username and password are used instead of a service principal.
Does ANF store the login credentials or use them once to grab a token and subsequently use that for authorization with AD?
ANF uses the credentials to create computer accounts in AD DS. The AD connection admin account supports Kerberos AES-128 and AES-256 encryption types for authentication with AD DS for Azure NetApp Files computer account creation[1]. This means that the credentials are used to establish the connection and perform necessary operations.
If a particular user is used to set up the ANF-AD connection and that user is later removed from the directory, will ANF lose the access it needs to function?
Yes, if the user account used to set up the ANF-AD connection is removed from the directory, ANF will lose the access it needs to function. It is important to ensure that the user account remains active and has the necessary permissions to maintain the connection
For more detailed guidance, you can refer to the Microsoft Learn article on creating and managing Active Directory connections for Azure NetApp Files Create and manage Active Directory connections for Azure NetApp Files | Microsoft Learn