Perhaps one of the most useful features at your disposal when working with Azure SQL Databases is the ability to integrate your Azure Active Directory (Azure AD) login accountsa la Windows Authentication for on-premise SQL Server. There are numerous benefits in shifting away from SQL Server-only user accounts in favour of Azure AD:

  • Ensures consistent login identities across multiple services.
  • Can enforce password complexity and refresh rules more easily.
  • Once configured, they behave exactly the same as standard SQL Server only logins.
  • Supports advanced usage scenarios involving Azure AD, such as multi-factor authentication and Single Sign-On (SSO) via Active Directory Federation Services (ADFS).

Setup can be completed in a pinch, although you will need to allocate a single/group of user(s) as the Active Directory admin for the Azure SQL Server. You may also choose to take due care and precautions when choosing your Active Directory admin(s); one suggestion would be to use a unique service account for the Active Directory admin, with a strong password, instead of granting such extensive privileges to normal user accounts.

Regardless of how you go about configuring the feature, I would recommend using it where-ever you can, for both internal purposes and also for anyone who wishes to access your SQL Server from an external directory. This second scenario is, you may be surprised to hear, fully supported. It assumes, first off, that you have added this account to your directory as a Guest/External User account. Then, you just follow the normal steps to get the account created on your Azure SQL Server.

There is one major “gotcha” to bear in mind when doing this. Let’s assume that you have added john.smith@domain.co.uk to the Azure AD tenant test.onmicrosoft.com. You then go to setup this account to access a SQL Server instance on the tenant. You will more than likely receive the following error message when using the example syntax below to create the account:

CREATE USER [john.smith@domain.co.uk] FROM EXTERNAL PROVIDER

The issue is, thankfully, simple to understand and fix. When External user accounts are added onto your Active Directory, despite having the same login name that derives from their source directory, they are stored in the new directory with a different UserPrincipalName (UPN). Consider the above example – the UPN in the source directory would be as follows:

john.smith@domain.co.uk

Whereas, as the Azure AD tenant name in this example is test.onmicrosoft.com, the UPN for the object would be:

john.smith_domain.co.uk#EXT#@test.onmicrosoft.com

I assume that this is done to prevent any UPN duplication across Microsoft’s no-doubt dizzying array of cloud Active Directory tenants and forests. In any event, knowing this, we can adjust our code above to suit – and successfully create our Database user account:

CREATE USER [john.smith_domain.co.uk#EXT#@test.onmicrosoft.com] FROM EXTERNAL PROVIDER

I guess this is one of those things where having at least a casual awareness of how other technologies within the Microsoft “stack” work can assist you greatly in troubleshooting what turn out to be simplistic errors in your code. Frustrating all the same, but we can claim knowledge of an obscure piece of Azure AD trivia as our end result 🙂

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