它工作得很好，不知道发生了什么变化，突然出现了这个错误。
hdfs在docker集群上运行（1个rm+2个节点）。
在容器中工作良好，因此数据节点没有问题。
使用代码或hdfs命令将文件从主机复制到hdfs时引发。
错误堆栈来自hadoop-root-namenode-master.log。

2017-10-26 09:18:05,102 WARN org.apache.hadoop.hdfs.protocol.BlockStoragePolicy: Failed to place enough replicas: expected size is 2 but only 0 storage types can be selected (replication=2, selected=[], unavailable=[DISK], removed=[DISK, DISK], policy=BlockStoragePolicy{HOT:7, storageTypes=[DISK], creationFallbacks=[], replicationFallbacks=[ARCHIVE]})
2017-10-26 09:18:05,102 WARN org.apache.hadoop.hdfs.server.blockmanagement.BlockPlacementPolicy: Failed to place enough replicas, still in need of 2 to reach 2 (unavailableStorages=[DISK], storagePolicy=BlockStoragePolicy{HOT:7, storageTypes=[DISK], creationFallbacks=[], replicationFallbacks=[ARCHIVE]}, newBlock=true) All required storage types are unavailable:  unavailableStorages=[DISK], storagePolicy=BlockStoragePolicy{HOT:7, storageTypes=[DISK], creationFallbacks=[], replicationFallbacks=[ARCHIVE]}
2017-10-26 09:18:05,103 INFO org.apache.hadoop.ipc.Server: IPC Server handler 7 on 9000, call org.apache.hadoop.hdfs.protocol.ClientProtocol.addBlock from 192.168.1.6:52435 Call#7 Retry#0
java.io.IOException: File /spark/apps/spark-app.jar 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:1571)
    at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.getNewBlockTargets(FSNamesystem.java:3107)
    at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.getAdditionalBlock(FSNamesystem.java:3031)
    at org.apache.hadoop.hdfs.server.namenode.NameNodeRpcServer.addBlock(NameNodeRpcServer.java:725)
    at org.apache.hadoop.hdfs.protocolPB.ClientNamenodeProtocolServerSideTranslatorPB.addBlock(ClientNamenodeProtocolServerSideTranslatorPB.java:492)
    at org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos$ClientNamenodeProtocol$2.callBlockingMethod(ClientNamenodeProtocolProtos.java)
    at org.apache.hadoop.ipc.ProtobufRpcEngine$Server$ProtoBufRpcInvoker.call(ProtobufRpcEngine.java:616)
    at org.apache.hadoop.ipc.RPC$Server.call(RPC.java:982)
    at org.apache.hadoop.ipc.Server$Handler$1.run(Server.java:2049)
    at org.apache.hadoop.ipc.Server$Handler$1.run(Server.java:2045)
    at java.security.AccessController.doPrivileged(Native Method)
    at javax.security.auth.Subject.doAs(Subject.java:422)
    at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1698)
    at org.apache.hadoop.ipc.Server$Handler.run(Server.java:2043)

源代码是：

System.setProperty("HADOOP_USER_NAME", "root");
    Configuration conf = new Configuration();
    conf.addResource(new Path("src/main/resources/core-site.xml"));      
    FileSystem fs = FileSystem.get(conf);
    fs.copyFromLocalFile(new Path(jars/spark-app.jar"), new Path("/spark/apps/spark-app.jar"));