启动Flink的yarnsession模式出错

　　问题如下：bin/yarn-session.sh -d 报错

 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：日志中显示的大概原因就行启动失败，资源不够，但是我启动的时候并没有指定任何参数，使用的是默认值，申请的资源大小绝对不会超过可用的资源大小，完全够用，所以报错原因跟运行时指定的参数无关，那么我们该如何解决呢？

　　解决：之前测试时启动太多次Filnk的yarn-session模式，所以断定是临时文件过多导致，故删除HDFS中的Flink的临时文件即可，你的文件存在哪就删除哪，我存在/flink/yarn/ha目录下，所以直接删除即可，可以在flink的conf目录下的flink-conf.yaml查看HDFS的存储路径

　　再次启动，发现启动成功

bin/yarn-session.sh -d