Mitesh Shah provides some high-level information on how to secure a MapR cluster:
Security Best Practice #2: Require Authentication for All Services. While it’s important for ports to be accessible exclusively from the network segment(s) that require access, you need to go a step further to ensure that only specific users are authorized to access the services running on these ports. All MapR services — regardless of their accessibility — should require authentication. A good way to enforce this for MapR platform components is by turning on security. Note that MapR is the only big data platform that allows for username/password-based authentication with the user registry of your choice, obviating the need for Kerberos and all the complexities that Kerberos brings (e.g., setting up and managing a KDC). MapR supports Kerberos, too, so environments that already have it running can use it with MapR if preferred.
There’s nothing here which is absolutely groundbreaking, but they are good practices.