NoRouteToHost exception on Hadoop 0.20.1

[Arijit Mukherjee <ar...@gmail.com>]

Hi

I installed Hadoop 0.20.1 on a CentOS system (with all required
pre-requisites, such as JDK 1.6, sshd etc). The stand alone test (as
mentioned in the Quick Start guide) worked fine. But when I use the
pseudo-distributed config (again following the quick start guide), the
reduce jobs get stalled for a long time, and ultimately fails. When I
looked at the logs, I found this exception -

2009-10-09 12:02:22,900 WARN org.apache.hadoop.mapred.ReduceTask:
java.net.NoRouteToHostException: No route to host
	at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
	at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39)
	at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27)
	at java.lang.reflect.Constructor.newInstance(Constructor.java:513)
	at sun.net.www.protocol.http.HttpURLConnection$6.run(HttpURLConnection.java:1296)
	at java.security.AccessController.doPrivileged(Native Method)
	at sun.net.www.protocol.http.HttpURLConnection.getChainedException(HttpURLConnection.java:1290)
	at sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:944)
	at org.apache.hadoop.mapred.ReduceTask$ReduceCopier$MapOutputCopier.getInputStream(ReduceTask.java:1447)
	at org.apache.hadoop.mapred.ReduceTask$ReduceCopier$MapOutputCopier.getMapOutput(ReduceTask.java:1349)
	at org.apache.hadoop.mapred.ReduceTask$ReduceCopier$MapOutputCopier.copyOutput(ReduceTask.java:1261)
	at org.apache.hadoop.mapred.ReduceTask$ReduceCopier$MapOutputCopier.run(ReduceTask.java:1195)

I've searched for this kind of exception - but couldn't find a fix. My
firewall is disabled, passwordless ssh is enabled. What am I doing
wrong here?

Thanx in advance.

Regards
Arijit
-- 
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