Question

我正在尝试在本地计算机上启动hadoop单节点群集。我根据https://amodernstory.com/2014/09/23/installing-hadoop-on-mac-osx-yosemite/配置了以下文件：hadoop-env.sh，core-site.xml，mapred-site.xml和hdfs-site.xml。当我运行脚本start-dfs.sh然后运行命令jps（在运行start-dfs.sh之后）时，我看到datanode已启动并运行：

15735 Jps
15548 DataNode
15660 SecondaryNameNode
15453 NameNode

几秒钟后，我重新运行命令jps，我发现datanode没有运行。为什么？如何解决这个问题？

之后我运行脚本start-yarn.sh，然后运行命令jps。我明白这一点：

15955 NodeManager
16011 Jps
15660 SecondaryNameNode
15453 NameNode
15854 ResourceManager

我的最终目标是从我的本地文件系统将文件复制到HDFS中。为此，我运行命令hdfs dfs -copyFromLocal /source-file-path/filename /destination-file-path/。我收到以下错误：

17/07/10 17:09:00 WARN hdfs.DataStreamer: DataStreamer Exception
org.apache.hadoop.ipc.RemoteException(java.io.IOException): File /pay/txnlinking/redshift.yml._COPYING_ could only be replicated to 0 nodes instead of minReplication (=1).  There are 0 datanode(s) running and no node(s) are excluded in this operation.
    at org.apache.hadoop.hdfs.server.blockmanagement.BlockManager.chooseTarget4NewBlock(BlockManager.java:1733)
    at org.apache.hadoop.hdfs.server.namenode.FSDirWriteFileOp.chooseTargetForNewBlock(FSDirWriteFileOp.java:265)
    at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.getAdditionalBlock(FSNamesystem.java:2496)
    at org.apache.hadoop.hdfs.server.namenode.NameNodeRpcServer.addBlock(NameNodeRpcServer.java:828)
    at org.apache.hadoop.hdfs.protocolPB.ClientNamenodeProtocolServerSideTranslatorPB.addBlock(ClientNamenodeProtocolServerSideTranslatorPB.java:506)
    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$RpcCall.run(Server.java:845)
    at org.apache.hadoop.ipc.Server$RpcCall.run(Server.java:788)
    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:1807)
    at org.apache.hadoop.ipc.Server$Handler.run(Server.java:2455)

    at org.apache.hadoop.ipc.Client.getRpcResponse(Client.java:1481)
    at org.apache.hadoop.ipc.Client.call(Client.java:1427)
    at org.apache.hadoop.ipc.Client.call(Client.java:1337)
    at org.apache.hadoop.ipc.ProtobufRpcEngine$Invoker.invoke(ProtobufRpcEngine.java:227)
    at org.apache.hadoop.ipc.ProtobufRpcEngine$Invoker.invoke(ProtobufRpcEngine.java:116)
    at com.sun.proxy.$Proxy10.addBlock(Unknown Source)
    at org.apache.hadoop.hdfs.protocolPB.ClientNamenodeProtocolTranslatorPB.addBlock(ClientNamenodeProtocolTranslatorPB.java:440)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at org.apache.hadoop.io.retry.RetryInvocationHandler.invokeMethod(RetryInvocationHandler.java:398)
    at org.apache.hadoop.io.retry.RetryInvocationHandler$Call.invokeMethod(RetryInvocationHandler.java:163)
    at org.apache.hadoop.io.retry.RetryInvocationHandler$Call.invoke(RetryInvocationHandler.java:155)
    at org.apache.hadoop.io.retry.RetryInvocationHandler$Call.invokeOnce(RetryInvocationHandler.java:95)
    at org.apache.hadoop.io.retry.RetryInvocationHandler.invoke(RetryInvocationHandler.java:335)
    at com.sun.proxy.$Proxy11.addBlock(Unknown Source)
    at org.apache.hadoop.hdfs.DataStreamer.locateFollowingBlock(DataStreamer.java:1733)
    at org.apache.hadoop.hdfs.DataStreamer.nextBlockOutputStream(DataStreamer.java:1536)
    at org.apache.hadoop.hdfs.DataStreamer.run(DataStreamer.java:658)
copyFromLocal: File /pay/txnlinking/redshift.yml._COPYING_ could only be replicated to 0 nodes instead of minReplication (=1).  There are 0 datanode(s) running and no node(s) are excluded in this operation.

如何避免上述错误并将文件复制到HDFS中？

P.S：我在进行复制之前明确地在HDFS中创建了目标路径文件夹。

Answer 1

做

hadoop namenode -format

然后使用

停止所有服务

stop-all.sh

然后使用

重启所有服务

start-all.sh

不推荐使用start-all.sh和stop-all.sh使用start-dfs.sh和stop-dfs.sh而不是

Answer 2

首先删除您在core-site.xml中指定的hadoop.tmp.dir文件夹的内容。然后使用hdfs namenode -format执行namenode格式。您的datanode应该正常启动并运行，之后将成功执行所有复制操作。

如何将文件复制到HDFS？

2 个答案: