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MapReduce, mail # user - Map tasks never getting started


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Re: Map tasks never getting started
Harsh J 2013-04-12, 10:23
The default mapping comes from the rack awareness script, not the
topology data file it uses. Also, note that if you start a TT or DN
before you update the topology data and refresh it, the default rack
value gets assigned instead.

On Fri, Apr 12, 2013 at 3:42 PM, sandeep reddy
<[EMAIL PROTECTED]> wrote:
> Harsh,
>
> My topology file looks similar as following:
>
> 192.168.2.20 host1.example.com host1 /tc/rack1
> 192.168.2.21 host2.example.com host2 /tc/rack1
> 192.168.2.22 host3.example.com host3 /tc/rack1
> 192.168.2.23 host4.example.com host4 /tc/rack2
> 192.168.2.24 host5.example.com host5 /tc/rack2
>
> If I am not wrong all hosts have the same levers.
>
> Can you please let me know how to including the default rack value used
> upon a mismatch?
>
> Thanks,
> Sandeep.
> ________________________________
> From: Harsh J <[EMAIL PROTECTED]>
> To: "<[EMAIL PROTECTED]>" <[EMAIL PROTECTED]>; sandeep reddy
> <[EMAIL PROTECTED]>
> Sent: Friday, April 12, 2013 3:22 PM
> Subject: Re: Map tasks never getting started
>
> Your rack topology configuration is broken (mismatching levels) and
> you're therefore hitting MAPREDUCE-1740. Either upgrade to a more
> current release, or fix your rack configuration to be of the same
> levels for all mapped nodes (including the default rack value used
> upon a mismatch) and restart the JobTracker.
>
> On Fri, Apr 12, 2013 at 3:15 PM, sandeep reddy
> <[EMAIL PROTECTED]> wrote:
>> Hi,
>>
>> While running a mapred job map task never getting assigned. The message
>> for
>> a map in web interface is "No Task Attempts found".
>> When I check the logs there are couple of errors as following:
>>
>> 2013-04-12 02:29:04,454 ERROR
>> org.apache.hadoop.security.UserGroupInformation:
>> PriviledgedActionException
>> as:jobs cause:java.io.IOException: java.lang.NullPointerException
>> 2013-04-12 02:29:04,455 INFO org.apache.hadoop.ipc.Server: IPC Server
>> handler 8 on 4571, call
>> heartbeat(org.apache.hadoop.mapred.TaskTrackerStatus@8f9c09e, false,
>> false,
>> true, 4) from 192.168.2.20:59968: error: java.io.IOException:
>> java.lang.NullPointerException
>> java.io.IOException: java.lang.NullPointerException
>>        at
>>
>> org.apache.hadoop.mapred.JobInProgress.getMatchingLevelForNodes(JobInProgress.java:1699)
>>        at
>>
>> org.apache.hadoop.mapred.JobInProgress.addRunningTaskToTIP(JobInProgress.java:1784)
>>        at
>>
>> org.apache.hadoop.mapred.JobInProgress.obtainNewNonLocalMapTask(JobInProgress.java:1440)
>>        at
>>
>> org.apache.hadoop.mapred.JobQueueTaskScheduler.assignTasks(JobQueueTaskScheduler.java:189)
>>        at
>> org.apache.hadoop.mapred.JobTracker.heartbeat(JobTracker.java:3398)
>>        at sun.reflect.GeneratedMethodAccessor2.invoke(Unknown Source)
>>        at
>>
>> sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
>>        at java.lang.reflect.Method.invoke(Method.java:601)
>>        at org.apache.hadoop.ipc.RPC$Server.call(RPC.java:563)
>>        at org.apache.hadoop.ipc.Server$Handler$1.run(Server.java:1388)
>>        at org.apache.hadoop.ipc.Server$Handler$1.run(Server.java:1384)
>>        at java.security.AccessController.doPrivileged(Native Method)
>>        at javax.security.auth.Subject.doAs(Subject.java:415)
>>        at
>>
>> org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1093)
>>        at org.apache.hadoop.ipc.Server$Handler.run(Server.java:1382)
>> 2013-04-12 02:29:04,463 INFO org.apache.hadoop.mapred.JobTracker: Removing
>> task 'attempt_201304120228_0001_m_000002_0'
>>
>> Some please help me to resolve this issue.
>> I am using hadoop-1.0.2
>>
>> Thanks,
>> Sandeep.
>
>
>
> --
> Harsh J
>
>

--
Harsh J