我正在尝试从vpc之外的外部客户端通过emr向hdfs写入数据。引发以下错误：

Caused by: org.apache.hadoop.ipc.RemoteException(java.io.IOException): File /user/sdc/temperature-humidity/2018-03-22-04/_tmp_sdc-5bb89fd7-1b80-11e8-95f0-251c07cb2860_0 could only be replicated to 0 nodes instead of minReplication (=1).  There are 2 datanode(s) running and 2 node(s) are excluded in this operation.
    at org.apache.hadoop.hdfs.server.blockmanagement.BlockManager.chooseTarget4NewBlock(BlockManager.java:1735)
    at org.apache.hadoop.hdfs.server.namenode.FSDirWriteFileOp.chooseTargetForNewBlock(FSDirWriteFileOp.java:265)
    at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.getAdditionalBlock(FSNamesystem.java:2561)
    at org.apache.hadoop.hdfs.server.namenode.NameNodeRpcServer.addBlock(NameNodeRpcServer.java:829)
    at org.apache.hadoop.hdfs.protocolPB.ClientNamenodeProtocolServerSideTranslatorPB.addBlock(ClientNamenodeProtocolServerSideTranslatorPB.java:510)
    at org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos$ClientNamenodeProtocol$2.callBlockingMethod(ClientNamenodeProtocolProtos.java)
    at org.apache.hadoop.ipc.ProtobufRpcEngine$Server$ProtoBufRpcInvoker.call(ProtobufRpcEngine.java:447)
    at org.apache.hadoop.ipc.RPC$Server.call(RPC.java:989)
    at org.apache.hadoop.ipc.Server$RpcCall.run(Server.java:847)
    at org.apache.hadoop.ipc.Server$RpcCall.run(Server.java:790)
    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:1836)
    at org.apache.hadoop.ipc.Server$Handler.run(Server.java:2486)
    at org.apache.hadoop.ipc.Client.getRpcResponse(Client.java:1554)
    at org.apache.hadoop.ipc.Client.call(Client.java:1498)
    at org.apache.hadoop.ipc.Client.call(Client.java:1398)
    at org.apache.hadoop.ipc.ProtobufRpcEngine$Invoker.invoke(ProtobufRpcEngine.java:233)
    at com.sun.proxy.$Proxy102.addBlock(Unknown Source)
    at org.apache.hadoop.hdfs.protocolPB.ClientNamenodeProtocolTranslatorPB.addBlock(ClientNamenodeProtocolTranslatorPB.java:459)
    at sun.reflect.GeneratedMethodAccessor212.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at org.apache.hadoop.io.retry.RetryInvocationHandler.invokeMethod(RetryInvocationHandler.java:291)
    at org.apache.hadoop.io.retry.RetryInvocationHandler.invoke(RetryInvocationHandler.java:203)
    at org.apache.hadoop.io.retry.RetryInvocationHandler.invoke(RetryInvocationHandler.java:185)
    at com.sun.proxy.$Proxy103.addBlock(Unknown Source)
    at org.apache.hadoop.hdfs.DFSOutputStream$DataStreamer.locateFollowingBlock(DFSOutputStream.java:1574)
    at org.apache.hadoop.hdfs.DFSOutputStream$DataStreamer.nextBlockOutputStream(DFSOutputStream.java:1369)
    at org.apache.hadoop.hdfs.DFSOutputStream$DataStreamer.run(DFSOutputStream.java:558)

作业在hdfs上创建空文件：

$ hdfs dfs -ls -R /user/sdc/temperature-humidity
drwxr-xr-x   - sdc sdc          0 2018-03-22 15:06 /user/sdc/temperature-humidity/2018-03-22-15
-rw-r--r--   3 sdc sdc          0 2018-03-22 15:04 /user/sdc/temperature-humidity/2018-03-22-15/sdc-5bb89fd7-1b80-11e8-95f0-251c07cb2860_343b936c-e72f-4ba0-8dd3-6c2ccf819cd8

我注意到datanodes使用的是内部名称和私有ip：

hdfs$ hdfs dfsadmin -report | grep -i name
Name: 172.31.11.201:50010 (ip-172-31-11-201.us-east-2.compute.internal)
Hostname: ip-172-31-11-201.us-east-2.compute.internal
Name: 172.31.3.174:50010 (ip-172-31-3-174.us-east-2.compute.internal)
Hostname: ip-172-31-3-174.us-east-2.compute.internal

我怀疑客户端可以与namenode对话，因为它有一个公共dns。它在名称空间中创建文件条目，但随后无法将数据写入datanode，因为namenode告诉客户机写入其内部名称，而这些名称在vpc外部是不可解析的，例如。

q） 如何配置我的emr和/或客户机，使其能够从专有网络外部写入emr HDF？