Hadoop: FileNotFoundExcepion when getting file from DistributedCache

问题

I’ve 2 nodes cluster (v1.04), master and slave. On the master, in Tool.run() we add two files to the DistributedCache using addCacheFile(). Files do exist in HDFS. In the Mapper.setup() we want to retrieve those files from the cache using

FSDataInputStream fs = FileSystem.get( context.getConfiguration() ).open( path ). 

The problem is that for one file a FileNotFoundException is thrown, although the file exists on the slave node:

attempt_201211211227_0020_m_000000_2: java.io.FileNotFoundException: File does not exist: /somedir/hdp.tmp.dir/mapred/local/taskTracker/distcache/-7769715304990780/master/tmp/analytics/1.csv

ls –l on the slave:

[hduser@slave ~]$ ll /somedir/hdp.tmp.dir/mapred/local/taskTracker/distcache/-7769715304990780/master/tmp/ analytics/1.csv                        
-rwxr-xr-x 1 hduser hadoop 42701 Nov 22 10:18 /somedir/hdp.tmp.dir/mapred/local/taskTracker/distcache/-7769715304990780/master/tmp/ analytics/1.csv

My questions are:

1. Shouldn't all files exist on all nodes?
2. What should be done to fix that?

Thanks.

回答1:

Solved - should have beed used:

FileSystem.getLocal( conf ) 

Thanks to Harsh J from Hadoop mailing list.

来源：https://stackoverflow.com/questions/13508707/hadoop-filenotfoundexcepion-when-getting-file-from-distributedcache