啟動Flink的yarn-session模式出錯

　　問題如下：bin/yarn-session.sh -d 報錯

 The program finished with the following exception:

org.apache.flink.client.deployment.ClusterDeploymentException: Couldn't deploy Yarn session cluster
    at org.apache.flink.yarn.YarnClusterDescriptor.deploySessionCluster(YarnClusterDescriptor.java:425)
    at org.apache.flink.yarn.cli.FlinkYarnSessionCli.run(FlinkYarnSessionCli.java:606)
    at org.apache.flink.yarn.cli.FlinkYarnSessionCli.lambda$main$4(FlinkYarnSessionCli.java:860)
    at java.security.AccessController.doPrivileged(Native Method)
    at javax.security.auth.Subject.doAs(Subject.java:422)
    at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1729)
    at org.apache.flink.runtime.security.contexts.HadoopSecurityContext.runSecured(HadoopSecurityContext.java:41)
    at org.apache.flink.yarn.cli.FlinkYarnSessionCli.main(FlinkYarnSessionCli.java:860)
Caused by: org.apache.flink.configuration.IllegalConfigurationException: The number of requested virtual cores for application master 1 exceeds the maximum number of virtual cores 0 available in the Yarn Cluster.
    at org.apache.flink.yarn.YarnClusterDescriptor.isReadyForDeployment(YarnClusterDescriptor.java:326)
    at org.apache.flink.yarn.YarnClusterDescriptor.deployInternal(YarnClusterDescriptor.java:534)
    at org.apache.flink.yarn.YarnClusterDescriptor.deploySessionCluster(YarnClusterDescriptor.java:418)
    ... 7 more

　　解析：日志中顯示的大概原因就行啟動失敗，資源不夠，但是我啟動的時候並沒有指定任何參數，使用的是默認值，申請的資源大小絕對不會超過可用的資源大小，完全夠用，所以報錯原因跟運行時指定的參數無關，那么我們該如何解決呢？

　　解決：之前測試時啟動太多次Filnk的yarn-session模式，所以斷定是臨時文件過多導致，故刪除HDFS中的Flink的臨時文件即可，你的文件存在哪就刪除哪，我存在/flink/yarn/ha目錄下，所以直接刪除即可，可以在flink的conf目錄下的flink-conf.yaml查看HDFS的存儲路徑

　　再次啟動，發現啟動成功

bin/yarn-session.sh -d