Authorizing `dse client-tool spark` and `dse spark`

To run the dse client-tool spark or dse spark using a non-superuser role, authorize the role to EXECUTE on the following resource:

REMOTE OBJECT DseClientTool

When an unauthorized user attempts to run the command, launch a spark console session, as shown in the following example:

dse -u jane -p password spark

An unauthorized error displays:

The log file is at /home/automaton/.spark-shell.log
ERROR 2018-07-10 19:23:04,382 org.apache.spark.deploy.DseSparkSubmitBootstrapper: Failed to start or submit Spark application because of com.datastax.driver.core.exceptions.UnauthorizedException: User jane has no EXECUTE permission on <rpc method DseClientTool.getSparkMetricsConfig> or any of its parents - see details in the log file(s): /home/automaton/.spark-shell.log
ERROR 2018-07-10 19:23:04,682 org.apache.spark.deploy.DseSparkSubmitBootstrapper: Failed to cancel delegation token

Procedure

Log in to cqlsh with an account that has authorization permission on remote objects.
```
cqlsh -u sec_admin
```

Give EXECUTE permission to the role.

GRANT EXECUTE ON REMOTE OBJECT DseClientTool TO jane;

Optional: Test that a user with the role, for example, jane, can execute a command.

dse -u jane -p password spark

The log file is at /home/automaton/.spark-shell.log
Creating a new Spark Session
Welcome to
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   /___/ .__/\_,_/_/ /_/\_\   version 2.2.0.14
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