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MapReduce >> mail # user >> hftp can list directories but won't send files

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Re: hftp can list directories but won't send files
What version/distribution of Hadoop is your source cluster?

Also, I'd take a look at a your NN's and a few of your DN's logs right
after encountering this issue, to see the reason+stacktrace printed
for the Server Error 500 (a code for a server-end fault). That'd give
us more ideas on whys.

On Wed, Dec 19, 2012 at 4:13 AM, Robert Rapplean
> Hey, everone. Just got finished reading about all of the unsubscribe messages in Sept-Oct, and was hoping someone has a clue about what my system is doing wrong. I suspect that this is a configuration issue, but I don't even know where to start looking for it. I'm a developer, and my sysadmin is tied up until the end of the year.
> I'm trying to move files from one cluster to another using distcp, using the hftp protocol as specified in their instructions.
> I can read directories over hftp, but when I attempt to get a file I get a 500 (internal server error). To eliminate the possibility of network and firewall issues, I'm using hadoop fs -ls and hadoop fs -cat commands on the source server in order to attempt to figure out this issue.
> This provides a directory of the files, which is correct.
> hadoop fs -ls ourlogs/day_id=19991231/hour_id=1999123123
> -rw-r--r--   3 username supergroup        812 2012-12-16 17:21 logfiles/day_id=19991231/hour_id=1999123123/000008_0
> This gives me a "file not found" error, which is also correct because the file isn't there:
> hadoop fs -cat hftp://hdenn00.trueffect.com:50070/user/username/logfiles/day_id=19991231/hour_id=1999123123/000008_0x
> cat: `hftp://hdenn00.trueffect.com:50070/user/prodman/ods_fail/day_id=19991231/hour_id=1999123123/000008_0x': No such file or directory
> This line gives me a 500 internal server error. The file is confirmed to be on the server.
> hadoop fs -cat hftp://hdenn00.trueffect.com:50070/user/username/logfiles/day_id=19991231/hour_id=1999123123/000008_0
> cat: HTTP_OK expected, received 500
> Here is a stack trace of what distcp logs when I attempt this:
> java.io.IOException: HTTP_OK expected, received 500
>     at org.apache.hadoop.hdfs.HftpFileSystem$RangeHeaderUrlOpener.connect(HftpFileSystem.java:365)
>     at org.apache.hadoop.hdfs.ByteRangeInputStream.openInputStream(ByteRangeInputStream.java:119)
>     at org.apache.hadoop.hdfs.ByteRangeInputStream.getInputStream(ByteRangeInputStream.java:103)
>     at org.apache.hadoop.hdfs.ByteRangeInputStream.read(ByteRangeInputStream.java:187)
>     at java.io.DataInputStream.read(DataInputStream.java:83)
>     at org.apache.hadoop.tools.DistCp$CopyFilesMapper.copy(DistCp.java:424)
>     at org.apache.hadoop.tools.DistCp$CopyFilesMapper.map(DistCp.java:547)
>     at org.apache.hadoop.tools.DistCp$CopyFilesMapper.map(DistCp.java:314)
>     at org.apache.hadoop.mapred.MapRunner.run(MapRunner.java:50)
>     at org.apache.hadoop.mapred.MapTask.runOldMapper(MapTask.java:393)
>     at org.apache.hadoop.mapred.MapTask.run(MapTask.java:327)
>     at org.apache.hadoop.mapred.Child$4.run(Child.java:268)
>     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:1332)
>     at org.apache.hadoop.mapred.Child.main(Child.java:262)
> Can someone tell me why hftp is failing to serve files, or at least where to look?

Harsh J