spark yarn任务的executor 无故 timeout之原因分析

问题：

         用  spark-submit --master yarn --deploy-mode cluster --driver-memory 2G --num-executors 6 --executor-memory 2G ~~~

提交任务时，最后一个executor 执行时间 超过了 160s 导致 timeout而退出，造成任务重新执行造成用时过长。具体请看下面介绍：

17/01/13 09:13:08 WARN spark.HeartbeatReceiver: Removing executor 5 with no recent heartbeats: 161684 ms exceeds timeout 120000 ms
17/01/13 09:13:08 ERROR cluster.YarnClusterScheduler: Lost executor 5 on slave10: Executor heartbeat timed out after 161684 ms
17/01/13 09:13:08 WARN scheduler.TaskSetManager: Lost task 0.0 in stage 0.0 (TID 0, slave10): ExecutorLostFailure (executor 5 exited caused by one of the running tasks) Reason: Executor heartbeat timed out after 161684 ms
17/01/13 09:13:08 INFO scheduler.DAGScheduler: Executor lost: 5 (epoch 0)
17/01/13 09:13:08 INFO cluster.YarnClusterSchedulerBackend: Requesting to kill executor(s) 5
17/01/13 09:13:08 INFO scheduler.TaskSetManager: Starting task 0.1 in stage 0.0 (TID 5, slave06, partition 0,RACK_LOCAL, 8029 bytes)
17/01/13 09:13:08 INFO storage.BlockManagerMasterEndpoint: Trying to remove executor 5 from BlockManagerMaster.
17/01/13 09:13:08 INFO storage.BlockManagerMasterEndpoint: Removing block manager BlockManagerId(5, slave10, 34439)
17/01/13 09:13:08 INFO storage.BlockManagerMaster: Removed 5 successfully in removeExecutor
17/01/13 09:13:08 INFO scheduler.DAGScheduler: Host added was in lost list earlier: slave10
17/01/13 09:13:08 INFO yarn.ApplicationMaster$AMEndpoint: Driver requested to kill executor(s) 5.
17/01/13 09:13:08 INFO scheduler.TaskSetManager: Finished task 0.1 in stage 0.0 (TID 5) in 367 ms on slave06 (5/5)
17/01/13 09:13:08 INFO scheduler.DAGScheduler: ResultStage 0 (saveAsNewAPIHadoopFile at DataFrameFunctions.scala:55) finished in 162.495 s

初步估计是  因为最后一步用到的计算多，但是 spark的堆外内存配置低 如下所示

spark.yarn.executor.memoryOverhead

executorMemory * 0.10, with minimum of 384

故加大配置，如下：
spark-submit --master yarn --deploy-mode cluster --driver-memory 2G --num-executors 6 --executor-memory 2G --conf spark.yarn.executor.memoryOverhead=512 --conf spark.yarn.driver.memoryOverhead=512

经测试上述问题不复存在！