Question

I setup Hadoop, formatted the HDFS, ran bin/start-all.sh, ran bin/stop-all.sh and had no problems.

Now every time I run bin/start-all.sh, the Task Tracker fails to start and I get the following entry in my the Task Tracker log.

    2012-03-27 21:22:03,842 ERROR org.apache.hadoop.mapred.TaskTracker: Can not start task tracker because java.io.IOException: Call to localhost/127.0.0.1:9001 failed on local exception: java.io.IOException: Connection reset by peer
    at org.apache.hadoop.ipc.Client.wrapException(Client.java:1065)
    at org.apache.hadoop.ipc.Client.call(Client.java:1033)
    at org.apache.hadoop.ipc.RPC$Invoker.invoke(RPC.java:224)
    at org.apache.hadoop.mapred.$Proxy5.getProtocolVersion(Unknown Source)
    at org.apache.hadoop.ipc.RPC.getProxy(RPC.java:364)
    at org.apache.hadoop.ipc.RPC.getProxy(RPC.java:347)
    at org.apache.hadoop.ipc.RPC.getProxy(RPC.java:389)
    at org.apache.hadoop.ipc.RPC.waitForProxy(RPC.java:319)
    at org.apache.hadoop.ipc.RPC.waitForProxy(RPC.java:295)
    at org.apache.hadoop.mapred.TaskTracker$3.run(TaskTracker.java:708)
    at java.security.AccessController.doPrivileged(Native Method)
    at javax.security.auth.Subject.doAs(Subject.java:396)
    at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1059)
    at org.apache.hadoop.mapred.TaskTracker.initialize(TaskTracker.java:704)
    at org.apache.hadoop.mapred.TaskTracker.(TaskTracker.java:1328)
    at org.apache.hadoop.mapred.TaskTracker.main(TaskTracker.java:3430)
Caused by: java.io.IOException: Connection reset by peer
    at sun.nio.ch.FileDispatcher.read0(Native Method)
    at sun.nio.ch.SocketDispatcher.read(SocketDispatcher.java:21)
    at sun.nio.ch.IOUtil.readIntoNativeBuffer(IOUtil.java:202)
    at sun.nio.ch.IOUtil.read(IOUtil.java:175)
    at sun.nio.ch.SocketChannelImpl.read(SocketChannelImpl.java:243)
    at org.apache.hadoop.net.SocketInputStream$Reader.performIO(SocketInputStream.java:55)
    at org.apache.hadoop.net.SocketIOWithTimeout.doIO(SocketIOWithTimeout.java:142)
    at org.apache.hadoop.net.SocketInputStream.read(SocketInputStream.java:155)
    at org.apache.hadoop.net.SocketInputStream.read(SocketInputStream.java:128)
    at java.io.FilterInputStream.read(FilterInputStream.java:116)
    at org.apache.hadoop.ipc.Client$Connection$PingInputStream.read(Client.java:343)
    at java.io.BufferedInputStream.fill(BufferedInputStream.java:218)
    at java.io.BufferedInputStream.read(BufferedInputStream.java:237)
    at java.io.DataInputStream.readInt(DataInputStream.java:370)
    at org.apache.hadoop.ipc.Client$Connection.receiveResponse(Client.java:767)
    at org.apache.hadoop.ipc.Client$Connection.run(Client.java:712)

2012-03-27 21:22:03,843 INFO org.apache.hadoop.mapred.TaskTracker: SHUTDOWN_MSG:

I have found some references to this elsewhere, but have been unable to find a solution. I must admit that I am new to Hadoop and honestly have no clue as to what this error is saying.

Any ideas or suggestions on things I can try would be greatly appreciated. I hope that I have posted enough information, but not too much. If more info is needed, please let me know.

Thanks in advance!

Answer 1

Have you confirmed that a job tracker is running on port 9001 for the local machine:

• Find the process id (pid) for the JobTracker (jps -v or ps axww | grep JobTracker)
• netstat -atnp | grep ${pid}
• Check the job tracker logs for any messages (ls -l /proc/${pid}/fd should list all the open files for the JobTracker, making location of the log file easier)