Question

I am, in the included test program, attempting to copy a file from the local disk to HDFS. The code is as follows:

package foo.foo1.foo2.test;

import java.io.IOException;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;

public class TestTestTest {

    public static void main(String[] args) {

    String srcLocation = "foo";
    String destination = "hdfs:///tmp/";

    FileSystem hdfs = null;

    Configuration configuration = new Configuration();
    configuration.set("fs.default.name", "hdfs://namenode:54310/");

    try {
        hdfs = FileSystem.get(configuration);
    } catch (IOException e2) {
        e2.printStackTrace();
        return;
    }

    Path srcpath = new Path(srcLocation);
    Path dstpath = new Path(destination);

    try {
        hdfs.copyFromLocalFile(srcpath, dstpath);
    } catch (IOException e) {
        e.printStackTrace();
    }

    }

}

This fails with the following exception:

java.io.IOException: Call to namenode/10.1.1.1:54310 failed on local exception:     java.io.EOFException
    at org.apache.hadoop.ipc.Client.wrapException(Client.java:775)
    at org.apache.hadoop.ipc.Client.call(Client.java:743)
    at org.apache.hadoop.ipc.RPC$Invoker.invoke(RPC.java:220)
    at $Proxy0.getProtocolVersion(Unknown Source)
    at org.apache.hadoop.ipc.RPC.getProxy(RPC.java:359)
    at org.apache.hadoop.hdfs.DFSClient.createRPCNamenode(DFSClient.java:106)
    at org.apache.hadoop.hdfs.DFSClient.<init>(DFSClient.java:207)
    at org.apache.hadoop.hdfs.DFSClient.<init>(DFSClient.java:170)
    at org.apache.hadoop.hdfs.DistributedFileSystem.initialize(DistributedFileSystem.java:82)
    at org.apache.hadoop.fs.FileSystem.createFileSystem(FileSystem.java:1378)
    at org.apache.hadoop.fs.FileSystem.access$200(FileSystem.java:66)
    at org.apache.hadoop.fs.FileSystem$Cache.get(FileSystem.java:1390)
    at org.apache.hadoop.fs.FileSystem.get(FileSystem.java:196)
    at org.apache.hadoop.fs.FileSystem.get(FileSystem.java:95)
    at foo.foo1.foo2.test.TestTestTest.main(TestTestTest.java:22)
Caused by: java.io.EOFException
    at java.io.DataInputStream.readInt(DataInputStream.java:375)
    at org.apache.hadoop.ipc.Client$Connection.receiveResponse(Client.java:501)
    at org.apache.hadoop.ipc.Client$Connection.run(Client.java:446)

My question is deceptively simple: What is causing this, and how can I make this program work? From what little information I’ve been able to find, I gather that there is a problem connecting to HDFS, and that this has something to do with the fs.default.name property in the Configuration. Below is the relevant section of my core-site.xml file:

<configuration>
  <property>
    <name>fs.default.name</name>
    <value>hdfs://namenode:54310</value>
  </property>

</configuration>

Perhaps of special interest is the fact that if I bundle all the jars in my classpath into one mega-jar, and run this program via the hadoop command, it works just fine. So what am I doing wrong?

Answer 1

Make sure you are compiling against the same Hadoop version that you are running on your cluster.