System assigned vs User assigned identity in Azure

#azure #beginners

User assigned identity

let the function app to read/manage azure resources
can be assigned to multiple resources and we have more flexibility when using user-assigned identity

System assigned identity

let the function app to connect to sql db using its own identity instead of username + password, which is less secure
solely used by one resource
with this, SQL_CONNECTION_STRING in configuration doesn't require to contain username or password. Instead, it sets Authentication to Active Directory Managed Identity
to be able to use this, you should

1.enable function app system assigned identity by clicking Identity> Status On

2.add user assigned identity

***NOTE: make sure to change IdentityId in configuration to the client (applicaton) Id of the user assigned identity

3.update SQL_CONNECTION_STRING in configuration to use Active Directory Managed Identity

4.In sql db, create a function app as sql user and make it as db_owner

CREATE USER [function app name] 
FROM EXTERNAL PROVIDER 
WITH DEFAULT_SCHEMA = dbo;  

ALTER ROLE db_owner ADD MEMBER [function app name];

5.you can test your function code by clicking your function app > Code+Test > Test/Run > Run

6.you can see the result by clicking Monitor

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