java向hdfs写入文件出错

Question

java向HDFS中写文件报错

使用docker容器构建hadoop集群，java api写文件时报错。Exception in thread "main" org.apache.hadoop.ipc.RemoteException(java.io.IOException): File /lessons/lesson2/zhl/javaApi/test1.txt could only be written to 0 of the 1 minReplication nodes. There are 2 datanode(s) running and 2 node(s) are excluded in this operation.

public class HDFSJavaApi {

    // 设置HDFS默认访问地址：
    public final static String HDFS_PATH = "hdfs://127.0.0.1:9000";
    // 配置对象声明
    private static Configuration configuration = null;
    // HDFS文件系统对象声明
    private static FileSystem fs = null;

    public static void main(String[] args) throws IOException, URISyntaxException, InterruptedException {

        // 开启HDFS链接
        setUp();
        // 4. 创建文件并写入数据, 在"/lessons/lesson2/zhl/javaApi/test1.txt", 并写入"Hello HDFS test1"
        //    调用接口`fs.create()`
        String filePath = "/lessons/lesson2/zhl/javaApi/test1.txt";
        String content = "Hello HDFS test1111\n";
        create(filePath, content);

Exception in thread "main" org.apache.hadoop.ipc.RemoteException(java.io.IOException): File /lessons/lesson2/zhl/javaApi/test1.txt could only be written to 0 of the 1 minReplication nodes. 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:2205)
at org.apache.hadoop.hdfs.server.namenode.FSDirWriteFileOp.chooseTargetForNewBlock(FSDirWriteFileOp.java:294)
at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.getAdditionalBlock(FSNamesystem.java:2731)
at org.apache.hadoop.hdfs.server.namenode.NameNodeRpcServer.addBlock(NameNodeRpcServer.java:892)
at org.apache.hadoop.hdfs.protocolPB.ClientNamenodeProtocolServerSideTranslatorPB.addBlock(ClientNamenodeProtocolServerSideTranslatorPB.java:568)
at org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos$ClientNamenodeProtocol$2.callBlockingMethod(ClientNamenodeProtocolProtos.java)
at org.apache.hadoop.ipc.ProtobufRpcEngine$Server$ProtoBufRpcInvoker.call(ProtobufRpcEngine.java:527)
at org.apache.hadoop.ipc.RPC$Server.call(RPC.java:1036)
at org.apache.hadoop.ipc.Server$RpcCall.run(Server.java:1000)
at org.apache.hadoop.ipc.Server$RpcCall.run(Server.java:928)
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.hadoop.ipc.Server$Handler.run(Server.java:2916)

at org.apache.hadoop.ipc.Client.getRpcResponse(Client.java:1545)
at org.apache.hadoop.ipc.Client.call(Client.java:1491)
at org.apache.hadoop.ipc.Client.call(Client.java:1388)
at org.apache.hadoop.ipc.ProtobufRpcEngine$Invoker.invoke(ProtobufRpcEngine.java:233)
at org.apache.hadoop.ipc.ProtobufRpcEngine$Invoker.invoke(ProtobufRpcEngine.java:118)
at jdk.proxy2/jdk.proxy2.$Proxy12.addBlock(Unknown Source)
at org.apache.hadoop.hdfs.protocolPB.ClientNamenodeProtocolTranslatorPB.addBlock(ClientNamenodeProtocolTranslatorPB.java:514)
at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:104)
at java.base/java.lang.reflect.Method.invoke(Method.java:577)
at org.apache.hadoop.io.retry.RetryInvocationHandler.invokeMethod(RetryInvocationHandler.java:422)
at org.apache.hadoop.io.retry.RetryInvocationHandler$Call.invokeMethod(RetryInvocationHandler.java:165)
at org.apache.hadoop.io.retry.RetryInvocationHandler$Call.invoke(RetryInvocationHandler.java:157)
at org.apache.hadoop.io.retry.RetryInvocationHandler$Call.invokeOnce(RetryInvocationHandler.java:95)
at org.apache.hadoop.io.retry.RetryInvocationHandler.invoke(RetryInvocationHandler.java:359)
at jdk.proxy2/jdk.proxy2.$Proxy13.addBlock(Unknown Source)
at org.apache.hadoop.hdfs.DFSOutputStream.addBlock(DFSOutputStream.java:1081)
at org.apache.hadoop.hdfs.DataStreamer.locateFollowingBlock(DataStreamer.java:1866)
at org.apache.hadoop.hdfs.DataStreamer.nextBlockOutputStream(DataStreamer.java:1668)
at org.apache.hadoop.hdfs.DataStreamer.run(DataStreamer.java:716)

查资料貌似是datanode节点ip不能被找到？？

Answer 1

原因有两种：
（1）namenode节点与其他datanode节点的VERSION中的clusterID的值不一致。
        方法：删除所有节点（包括namenode）节点的hdfs-site.xml中dfs.namenode.name.dir中指定的文件夹即name和data文件夹，然后使用hadoop namenode –format命令重新格式化各个节点。
（2）有节点的防火墙未关闭
        方法：使用命令：
        systemctl stop firewalld.service