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https://issues.apache.org/jira/browse/MAPREDUCE-5528?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14368080#comment-14368080
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Albert Chu commented on MAPREDUCE-5528:
---------------------------------------
Since I wrote my original patch, DistributedCache has been deprecated in favor
of using the job Context. Unfortunately, in TeraSort, there is no mapper or
reducer. All of the sorting is handled via the partitioner. As far as I can
tell, the Job context can't be accessed in the partitioner. B/c of that, this
really can't be handled through the patch I had before, assuming we don't want
to use deprecated code. Using the basic idea from [~ehiggs] in MAPREDUCE-5050
wouldn't have worked b/c the JobContext is again needed in newer versions of
FileOutputFormat.
I was trying to think of a clean way to do this but nothing came to mind each
of the ways I looked. I might just not see something that others would.
Open to suggestions.
> TeraSort fails with "can't read paritions file" - does not read partition
> file from distributed cache
> -----------------------------------------------------------------------------------------------------
>
> Key: MAPREDUCE-5528
> URL: https://issues.apache.org/jira/browse/MAPREDUCE-5528
> Project: Hadoop Map/Reduce
> Issue Type: Bug
> Components: examples
> Affects Versions: 0.20.2, 3.0.0, 2.5.0, 2.4.1, 2.6.0
> Reporter: Albert Chu
> Assignee: Albert Chu
> Priority: Minor
> Attachments: MAPREDUCE-5528.patch
>
>
> I was trying to run TeraSort against a parallel networked file system,
> setting things up via the 'file://" scheme. I always got the following error
> when running terasort:
> {noformat}
> 13/09/23 11:15:12 INFO mapreduce.Job: Task Id :
> attempt_1379960046506_0001_m_000080_1, Status : FAILED
> Error: java.lang.IllegalArgumentException: can't read paritions file
> at
> org.apache.hadoop.examples.terasort.TeraSort$TotalOrderPartitioner.setConf(TeraSort.java:254)
> at
> org.apache.hadoop.util.ReflectionUtils.setConf(ReflectionUtils.java:73)
> at
> org.apache.hadoop.util.ReflectionUtils.newInstance(ReflectionUtils.java:133)
> at
> org.apache.hadoop.mapred.MapTask$NewOutputCollector.<init>(MapTask.java:678)
> at org.apache.hadoop.mapred.MapTask.runNewMapper(MapTask.java:747)
> at org.apache.hadoop.mapred.MapTask.run(MapTask.java:340)
> at org.apache.hadoop.mapred.YarnChild$2.run(YarnChild.java:171)
> at java.security.AccessController.doPrivileged(Native Method)
> at javax.security.auth.Subject.doAs(Subject.java:396)
> at
> org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1499)
> at org.apache.hadoop.mapred.YarnChild.main(YarnChild.java:166)
> Caused by: java.io.FileNotFoundException: File _partition.lst does not exist
> at org.apache.hadoop.fs.Stat.parseExecResult(Stat.java:124)
> at org.apache.hadoop.util.Shell.runCommand(Shell.java:486)
> at org.apache.hadoop.util.Shell.run(Shell.java:417)
> at org.apache.hadoop.fs.Stat.getFileStatus(Stat.java:74)
> at
> org.apache.hadoop.fs.RawLocalFileSystem.getNativeFileLinkStatus(RawLocalFileSystem.java:808)
> at
> org.apache.hadoop.fs.RawLocalFileSystem.getFileLinkStatusInternal(RawLocalFileSystem.java:740)
> at
> org.apache.hadoop.fs.RawLocalFileSystem.getFileStatus(RawLocalFileSystem.java:525)
> at
> org.apache.hadoop.fs.FilterFileSystem.getFileStatus(FilterFileSystem.java:398)
> at
> org.apache.hadoop.fs.ChecksumFileSystem$ChecksumFSInputChecker.<init>(ChecksumFileSystem.java:137)
> at
> org.apache.hadoop.fs.ChecksumFileSystem.open(ChecksumFileSystem.java:339)
> at org.apache.hadoop.fs.FileSystem.open(FileSystem.java:763)
> at
> org.apache.hadoop.examples.terasort.TeraSort$TotalOrderPartitioner.readPartitions(TeraSort.java:161)
> at
> org.apache.hadoop.examples.terasort.TeraSort$TotalOrderPartitioner.setConf(TeraSort.java:246)
> ... 10 more
> {noformat}
> After digging into TeraSort, I noticed that the partitions file was created
> in the output directory, then added into the distributed cache
> {noformat}
> Path outputDir = new Path(args[1]);
> ...
> Path partitionFile = new Path(outputDir, TeraInputFormat.PARTITION_FILENAME);
> ...
> job.addCacheFile(partitionUri);
> {noformat}
> but the partitions file doesn't seem to be read back from the output
> directory or distributed cache:
> {noformat}
> FileSystem fs = FileSystem.getLocal(conf);
> ...
> Path partFile = new Path(TeraInputFormat.PARTITION_FILENAME);
> splitPoints = readPartitions(fs, partFile, conf);
> {noformat}
> It seems the file is being read from whatever the working directory is for
> the filesystem returned from FileSystem.getLocal(conf).
> Under HDFS this code works, the working directory seems to be the distributed
> cache (I guess by default??).
> But when I set things up with the networked file system and 'file://' scheme,
> the working directory was the directory I was running my Hadoop binaries out
> of.
> The attached patch fixed things for me. It grabs the partition file from the
> distributed cache all of the time, instead of trusting things underneath to
> work out. It seems to be the right thing to do???
> Apologies, I was unable to get this to reproduce under the TeraSort example
> tests, such as TestTeraSort.java, so no test added. Not sure what the subtle
> difference is in the setup. I tested under both HDFS & 'file' scheme and the
> patch worked under both.
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