在CDH5.5.2上运行spark1.5的程序，运行起来就直接shutdown，并报出如下的异常：
INFO YarnClientSchedulerBackend: SchedulerBackend is ready for scheduling beginning after waiting maxRegisteredResourcesWaitingTime: 30000(ms)
Exception in thread "main" java.lang.IllegalStateException: Cannot call methods on a stopped SparkContext
at org.apache.spark.SparkContext.org$apache$spark$SparkContext$$assertNotStopped(SparkContext.scala:104)
at org.apache.spark.SparkContext$$anonfun$newAPIHadoopRDD$1.apply(SparkContext.scala:1131)
at org.apache.spark.SparkContext$$anonfun$newAPIHadoopRDD$1.apply(SparkContext.scala:1130)
at org.apache.spark.rdd.RDDOperationScope$.withScope(RDDOperationScope.scala:147)
at org.apache.spark.rdd.RDDOperationScope$.withScope(RDDOperationScope.scala:108)
at org.apache.spark.SparkContext.withScope(SparkContext.scala:709)
at org.apache.spark.SparkContext.newAPIHadoopRDD(SparkContext.scala:1130)
at com.xxx.spark.etl$.parquetRun(AdEtl.scala:76)
at com.xxx.spark.etl$.main(AdEtl.scala:32)
at com.xxx.spark.etl.main(AdEtl.scala)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:606)
at org.apache.spark.deploy.SparkSubmit$.org$apache$spark$deploy$SparkSubmit$$runMain(SparkSubmit.scala:672)
at org.apache.spark.deploy.SparkSubmit$.doRunMain$1(SparkSubmit.scala:180)
at org.apache.spark.deploy.SparkSubmit$.submit(SparkSubmit.scala:205)
at org.apache.spark.deploy.SparkSubmit$.main(SparkSubmit.scala:120)
at org.apache.spark.deploy.SparkSubmit.main(SparkSubmit.scala)
出现这个问题时，尝试运行其他spark程序，能够正常运行，说明并不是spark不兼容问题导致的。那么什么原因导致的这个问题发生呢。继续查看yarn的日志，http://cloudera_master:8088查看所有yarn控制的程序，找到该异常的程序，查看运行日志：
16/05/23 15:48:53 ERROR ApplicationMaster: Uncaught exception: org.apache.hadoop.yarn.exceptions.InvalidResourceRequestException: Invalid resource request, requested virtual cores < 0, or requested virtual cores > max configured, requestedVirtualCores=6, maxVirtualCores=4 at org.apache.hadoop.yarn.server.resourcemanager.scheduler.SchedulerUtils.validateResourceRequest(SchedulerUtils.java:212) at org.apache.hadoop.yarn.server.resourcemanager.RMServerUtils.validateResourceRequests(RMServerUtils.java:96)收到如上的日志，通过这个日志可以很清楚的看到配置的执行器超出了最大执行数。所以异常了。 spark报出的异常并不是问题的真正异常，也就是出现问题的时候不要着急，一个地方发现不了问题，那么就多找几个地方，总会有发现问题的地方。