To use an existing Active Directory domain for the cluster, you must prepare the following:
Ambari Server and cluster hosts have network access to, and be able to resolve the DNS names of, the Domain Controllers.
Active Directory secure LDAP (LDAPS) connectivity has been configured.
Active Directory User container for principals has been created and is on-hand. For example, "OU=Hadoop,OU=People,dc=apache,dc=org"
Active Directory administrative credentials with delegated control of “Create, delete, and manage user accounts” on the previously mentioned User container are on-hand.
Proceed with Enabling Kerberos Security in Ambari.