From the HDF documenation it is clear that "NiFi does not perform user authentication over HTTP. Using HTTP, all users will be granted all roles."
https://docs.hortonworks.com/HDPDocuments/HDF3/HDF-3.4.1.1/nifi-security/content/user_authentication...
So it is mandatory to enabled Nifi ssl to have ldap_login_identity_provider
Hemanth