Spark- monitoring

1. Each spark-context has supervised URL: http: // <driver-node>: 4040, if there is more than the port number is 4041, 4042
2. The default monitor is only valid at runtime, if the job runs completely still need to be monitored, then open spark.eventLog.enabled
3. If the application logs exist, you can still monitor configuration UI:

   ./sbin/start-history-server.sh