报错是因为服务端YARN集群，需要和Spark driver通信时，因为服务端并没有配置客户端的域名解析，所以报java.net.UnknownHostException。

客户端报错

2021-06-01 14:20:21 WARN  YarnScheduler:66 - Initial job has not accepted any resources; check your cluster UI to ensure that workers are registered and have sufficient resources

服务端报错

2021-06-01 15:02:21 ERROR ApplicationMaster:91 - Uncaught exception: 
org.apache.spark.SparkException: Exception thrown in awaitResult: 
	at org.apache.spark.util.ThreadUtils$.awaitResult(ThreadUtils.scala:226)
	at org.apache.spark.rpc.RpcTimeout.awaitResult(RpcTimeout.scala:75)
	at org.apache.spark.rpc.RpcEnv.setupEndpointRefByURI(RpcEnv.scala:101)
	at org.apache.spark.rpc.RpcEnv.setupEndpointRef(RpcEnv.scala:109)
	at org.apache.spark.deploy.yarn.ApplicationMaster.runExecutorLauncher(ApplicationMaster.scala:514)
	at org.apache.spark.deploy.yarn.ApplicationMaster.org$apache$spark$deploy$yarn$ApplicationMaster$$runImpl(ApplicationMaster.scala:307)
	at org.apache.spark.deploy.yarn.ApplicationMaster$$anonfun$run$1.apply$mcV$sp(ApplicationMaster.scala:245)
	at org.apache.spark.deploy.yarn.ApplicationMaster$$anonfun$run$1.apply(ApplicationMaster.scala:245)
	at org.apache.spark.deploy.yarn.ApplicationMaster$$anonfun$run$1.apply(ApplicationMaster.scala:245)
	at org.apache.spark.deploy.yarn.ApplicationMaster$$anon$3.run(ApplicationMaster.scala:773)
	at java.security.AccessController.doPrivileged(Native Method)
	at javax.security.auth.Subject.doAs(Subject.java:422)
	at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1692)
	at org.apache.spark.deploy.yarn.ApplicationMaster.doAsUser(ApplicationMaster.scala:772)
	at org.apache.spark.deploy.yarn.ApplicationMaster.run(ApplicationMaster.scala:244)
	at org.apache.spark.deploy.yarn.ApplicationMaster$.main(ApplicationMaster.scala:797)
	at org.apache.spark.deploy.yarn.ExecutorLauncher$.main(ApplicationMaster.scala:827)
	at org.apache.spark.deploy.yarn.ExecutorLauncher.main(ApplicationMaster.scala)
Caused by: java.io.IOException: Failed to connect to bigdata01:39398
	at org.apache.spark.network.client.TransportClientFactory.createClient(TransportClientFactory.java:245)
	at org.apache.spark.network.client.TransportClientFactory.createClient(TransportClientFactory.java:187)
	at org.apache.spark.rpc.netty.NettyRpcEnv.createClient(NettyRpcEnv.scala:198)
	at org.apache.spark.rpc.netty.Outbox$$anon$1.call(Outbox.scala:194)
	at org.apache.spark.rpc.netty.Outbox$$anon$1.call(Outbox.scala:190)
	at java.util.concurrent.FutureTask.run(FutureTask.java:266)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
	at java.lang.Thread.run(Thread.java:748)
Caused by: java.net.UnknownHostException: bigdata01
	at java.net.InetAddress.getAllByName0(InetAddress.java:1280)
	at java.net.InetAddress.getAllByName(InetAddress.java:1192)

默认driver.host是通过域名的，可以手动指定成IP，将spark.driver.host配置成客户端的IP即可。

cd /opt/spark-2.4.0-bin-hadoop2.6/conf
vi spark-defaults.conf
 
spark.master=yarn
spark.submit.deployMode=client
spark.driver.host=192.168.X.X

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