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List:       hadoop-user
Subject:    Re: Hadoop+s3 & fuse-dfs
From:       Brian Bockelman <bbockelm () cse ! unl ! edu>
Date:       2009-01-29 12:49:53
Message-ID: AC2CB8C5-EC9D-46A3-9EEE-F791C0B0B5C3 () cse ! unl ! edu
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Hey all,

This is a long-shot, but I've noticed before that libhdfs doesn't load  
hadoop-site.xml *unless* hadoop-site.xml is in your local directory.

As a last try, maybe cd $HADOOP_HOME/conf and try running it from there?

Brian

On Jan 28, 2009, at 7:20 PM, Craig Macdonald wrote:

> Hi Roopa,
>
> Glad it worked :-)
>
> Please file JIRA issues against the fuse-dfs / libhdfs components  
> that would have made it easier to mount the S3 filesystem.
>
> Craig
>
> Roopa Sudheendra wrote:
>> Thanks, Yes a setup with fuse-dfs and hdfs works fine.I think the  
>> mount point was bad for whatever reason and was failing with that  
>> error .I created another mount point for mounting which resolved   
>> the transport end point error.
>>
>> Also i had -d option on my command..:)
>>
>>
>> Roopa
>>
>>
>> On Jan 28, 2009, at 6:35 PM, Craig Macdonald wrote:
>>
>>> Hi Roopa,
>>>
>>> Firstly, can you get the fuse-dfs working for an instance HDFS?
>>> There is also a debug mode for fuse: enable this by adding -d on  
>>> the command line.
>>>
>>> C
>>>
>>> Roopa Sudheendra wrote:
>>>> Hey Craig,
>>>> I tried the way u suggested..but i get this transport endpoint  
>>>> not connected. Can i see the logs anywhere? I dont see anything  
>>>> in /var/log/messages either
>>>> looks like it tries to create the file system in hdfs.c but not  
>>>> sure where it fails.
>>>> I have the hadoop home set so i believe it gets the config info.
>>>>
>>>> any idea?
>>>>
>>>> Thanks,
>>>> Roopa
>>>> On Jan 28, 2009, at 1:59 PM, Craig Macdonald wrote:
>>>>
>>>>> In theory, yes.
>>>>> On inspection of libhdfs, which underlies fuse-dfs, I note that:
>>>>>
>>>>> * libhdfs takes a host and port number as input when connecting,  
>>>>> but not a scheme (hdfs etc). The easiest option would be to set  
>>>>> the S3 as your default file system in your hadoop-site.xml, then  
>>>>> use the host of "default". That should get libhdfs to use the S3  
>>>>> file system. i.e. set fuse-dfs to mount dfs://default:0/ and all  
>>>>> should work as planned.
>>>>>
>>>>> * libhdfs also casts the FileSystem to a DistributedFileSystem  
>>>>> for the df command. This would fail in your case. This issue is  
>>>>> currently being worked on - see HADOOP-4368
>>>>> https://issues.apache.org/jira/browse/HADOOP-4368.
>>>>>
>>>>> C
>>>>>
>>>>>
>>>>> Roopa Sudheendra wrote:
>>>>>> Thanks for the response craig.
>>>>>> I looked at fuse-dfs c code and looks like it does not like  
>>>>>> anything other than "dfs:// " so with the fact that hadoop can  
>>>>>> connect to S3 file system ..allowing s3 scheme should solve my  
>>>>>> problem?
>>>>>>
>>>>>> Roopa
>>>>>>
>>>>>> On Jan 28, 2009, at 1:03 PM, Craig Macdonald wrote:
>>>>>>
>>>>>>> Hi Roopa,
>>>>>>>
>>>>>>> I cant comment on the S3 specifics. However, fuse-dfs is based  
>>>>>>> on a C interface called libhdfs which allows C programs (such  
>>>>>>> as fuse-dfs) to connect to the Hadoop file system Java API.  
>>>>>>> This being the case, fuse-dfs should (theoretically) be able  
>>>>>>> to connect to any file system that Hadoop can. Your mileage  
>>>>>>> may vary, but if you find issues, please do report them  
>>>>>>> through the normal channels.
>>>>>>>
>>>>>>> Craig
>>>>>>>
>>>>>>>
>>>>>>> Roopa Sudheendra wrote:
>>>>>>>> I am experimenting with Hadoop backed by Amazon s3 filesystem  
>>>>>>>> as one of our backup storage solution. Just the hadoop and  
>>>>>>>> s3(block based since it overcomes the 5gb limit) so far seems  
>>>>>>>> to be fine.
>>>>>>>> My problem is that i want to mount this filesystem using fuse- 
>>>>>>>> dfs ( since i don't have to worry about how the file is  
>>>>>>>> written on the system ) . Since the namenode does not get  
>>>>>>>> started with s3 backed hadoop system how can i connect fuse- 
>>>>>>>> dfs to this setup.
>>>>>>>>
>>>>>>>> Appreciate your help.
>>>>>>>> Thanks,
>>>>>>>> Roopa
>>>>>>>
>>>>>>
>>>>>
>>>>
>>>
>>

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