DUE TO SPAM, SIGN-UP IS DISABLED. Goto Selfserve wiki signup and request an account.
...
The RPC will require ALTER on CLUSTER. It will return CLUSTER_AUTHORIZATION_FAILED if the user has insufficient permissions.
It will disallow a user from altering any credential if the user authenticated with a delegation token and will return DELEGATION_TOKEN_REQUEST_NOT_ALLOWED in this case.It will be will be sent to the controller and will return NOT_CONTROLLER if the receiving broker is not the controller.
...