Spark management

Stored procedures for controlling the built-in Apache Spark engine.

Stored procedure name	Description
qua_spark_force_become_active	Transitions the node to Active, regardless of Zookeeper state.
qua_spark_force_become_standby	Transitions the node to StandBy, regardless of Zookeeper state.
qua_spark_instance_kill	Forces an OS-level kill on the given Spark process.
qua_spark_instance_start	Tries to find a running Spark process in the OS. If not found, a new process is started.
qua_spark_instance_stop	Sends a stop-server signal to the remote driver.
qua_spark_release	Releases Spark context and transitions driver to non-initialized state.
qua_spark_stop_driver	Sends a stop-server signal to the remote driver.