DSP-13401 Add a way to configure SJS launcher

DSE uses different launchers for different versions of Resource Managers.

Author: jtgrabowski

bin/manager_start.sh

@@ -59,7 +59,11 @@ if [ -n "$JOBSERVER_KEYTAB" ]; then
   SPARK_SUBMIT_OPTIONS="$SPARK_SUBMIT_OPTIONS --keytab $JOBSERVER_KEYTAB"
 fi
 
-cmd='$SPARK_HOME/bin/spark-submit --class $MAIN --driver-memory $JOBSERVER_MEMORY
+if [ -z "${SJS_LAUNCHER}" ]; then
+  export SJS_LAUNCHER="$SPARK_HOME/bin/spark-submit"
+fi
+
+cmd='$SJS_LAUNCHER --class $MAIN --driver-memory $JOBSERVER_MEMORY
       --conf "spark.executor.extraJavaOptions=$LOGGING_OPTS"
       $SPARK_SUBMIT_OPTIONS
       --driver-java-options "$GC_OPTS $JAVA_OPTS $LOGGING_OPTS $CONFIG_OVERRIDES $SPARK_SUBMIT_JAVA_OPTIONS"

bin/server_start.sh

@@ -43,7 +43,11 @@ if [ -f "$PIDFILE" ] && kill -0 $(cat "$PIDFILE"); then
    exit 1
 fi
 
-cmd='$SPARK_HOME/bin/spark-submit --class $MAIN --driver-memory $JOBSERVER_MEMORY
+if [ -z "${SJS_LAUNCHER}" ]; then
+  export SJS_LAUNCHER="$SPARK_HOME/bin/spark-submit"
+fi
+
+cmd='$SJS_LAUNCHER --class $MAIN --driver-memory $JOBSERVER_MEMORY
   --conf "spark.executor.extraJavaOptions=$LOGGING_OPTS"
   --driver-java-options "$GC_OPTS $JAVA_OPTS $LOGGING_OPTS $CONFIG_OVERRIDES"
   $@ $appdir/spark-job-server.jar $conffile'