Starting in the MEP 4.0 release, run -R to complete your Spark configuration when manually installing Spark or upgrading to a new version.

The command is the following:

/opt/mapr/server/ -R
Note: You do not need to run this script for new installs, if you are using the MapR installer in MEP 4.0 or later.

In the case of Spark Standalone and Spark on YARN, this is the last step in the configuration process. In the case of Spark on Mesos, run the script as the first step in Configuring Spark on Mesos. Running this script enables Spark security features if you have enabled security on your cluster.

All security configuration properties are specified within the following comment block in the SPARK_HOME/conf/spark-defaults.conf file:
Important: Do not remove these comments from the file, as well as any other comments within the block inserted by The script uses these comments to locate security properties.
Note: To set ports to special values, use the spark.driver.port and spark.blockManager.port properties.