hadoop-mapreduce-user mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Azuryy Yu <azury...@gmail.com>
Subject Re: File is not written on HDFS after running libhdfs C API
Date Thu, 05 Mar 2015 08:48:23 GMT
Can you share your core-site.xml here?


On Thu, Mar 5, 2015 at 4:32 PM, Alexandru Calin <alexandrucalin29@gmail.com>
wrote:

> No change at all, I've added them at the start and end of the CLASSPATH,
> either way it still writes the file on the local fs. I've also restarted
> hadoop.
>
> On Thu, Mar 5, 2015 at 10:22 AM, Azuryy Yu <azuryyyu@gmail.com> wrote:
>
>> Yes,  you should do it:)
>>
>> On Thu, Mar 5, 2015 at 4:17 PM, Alexandru Calin <
>> alexandrucalin29@gmail.com> wrote:
>>
>>> Wow, you are so right! it's on the local filesystem!  Do I have to
>>> manually specify hdfs-site.xml and core-site.xml in the CLASSPATH variable
>>> ? Like this:
>>> CLASSPATH=$CLASSPATH:/usr/local/hadoop/etc/hadoop/core-site.xml
>>> ?
>>>
>>> On Thu, Mar 5, 2015 at 10:04 AM, Azuryy Yu <azuryyyu@gmail.com> wrote:
>>>
>>>> you need to include core-site.xml as well. and I think you can find
>>>> '/tmp/testfile.txt' on your local disk, instead of HDFS.
>>>>
>>>> if so,  My guess is right.  because you don't include core-site.xml,
>>>> then your Filesystem schema is file:// by default, not hdfs://.
>>>>
>>>>
>>>>
>>>> On Thu, Mar 5, 2015 at 3:52 PM, Alexandru Calin <
>>>> alexandrucalin29@gmail.com> wrote:
>>>>
>>>>> I am trying to run the basic libhdfs example, it compiles ok, and
>>>>> actually runs ok, and executes the whole program, but I cannot see the
file
>>>>> on the HDFS.
>>>>>
>>>>> It is said  here <http://hadoop.apache.org/docs/r1.2.1/libhdfs.html>,
>>>>> that you have to include *the right configuration directory
>>>>> containing hdfs-site.xml*
>>>>>
>>>>> My hdfs-site.xml:
>>>>>
>>>>> <configuration>
>>>>>     <property>
>>>>>         <name>dfs.replication</name>
>>>>>         <value>1</value>
>>>>>     </property>
>>>>>     <property>
>>>>>       <name>dfs.namenode.name.dir</name>
>>>>>       <value>file:///usr/local/hadoop/hadoop_data/hdfs/namenode</value>
>>>>>     </property>
>>>>>     <property>
>>>>>       <name>dfs.datanode.data.dir</name>
>>>>>       <value>file:///usr/local/hadoop/hadoop_store/hdfs/datanode</value>
>>>>>     </property></configuration>
>>>>>
>>>>> I generate my classpath with this:
>>>>>
>>>>> #!/bin/bashexport CLASSPATH=/usr/local/hadoop/
>>>>> declare -a subdirs=("hdfs" "tools" "common" "yarn" "mapreduce")for subdir
in "${subdirs[@]}"do
>>>>>         for file in $(find /usr/local/hadoop/share/hadoop/$subdir -name
*.jar)
>>>>>         do
>>>>>                 export CLASSPATH=$CLASSPATH:$file
>>>>>         donedone
>>>>>
>>>>> and I also add export
>>>>> CLASSPATH=$CLASSPATH:/usr/local/hadoop/etc/hadoop , where my
>>>>> *hdfs-site.xml* reside.
>>>>>
>>>>> MY LD_LIBRARY_PATH =
>>>>> /usr/local/hadoop/lib/native:/usr/lib/jvm/java-7-openjdk-amd64/jre/lib/amd64/server
>>>>> Code:
>>>>>
>>>>> #include "hdfs.h"#include <stdio.h>#include <string.h>#include
<stdio.h>#include <stdlib.h>
>>>>> int main(int argc, char **argv) {
>>>>>
>>>>>     hdfsFS fs = hdfsConnect("default", 0);
>>>>>     const char* writePath = "/tmp/testfile.txt";
>>>>>     hdfsFile writeFile = hdfsOpenFile(fs, writePath, O_WRONLY|O_CREAT,
0, 0, 0);
>>>>>     if(!writeFile) {
>>>>>           printf("Failed to open %s for writing!\n", writePath);
>>>>>           exit(-1);
>>>>>     }
>>>>>     printf("\nfile opened\n");
>>>>>     char* buffer = "Hello, World!";
>>>>>     tSize num_written_bytes = hdfsWrite(fs, writeFile, (void*)buffer,
strlen(buffer)+1);
>>>>>     printf("\nWrote %d bytes\n", (int)num_written_bytes);
>>>>>     if (hdfsFlush(fs, writeFile)) {
>>>>>            printf("Failed to 'flush' %s\n", writePath);
>>>>>           exit(-1);
>>>>>     }
>>>>>    hdfsCloseFile(fs, writeFile);
>>>>>    hdfsDisconnect(fs);
>>>>>    return 0;}
>>>>>
>>>>> It compiles and runs without error, but I cannot see the file on HDFS.
>>>>>
>>>>> I have Hadoop 2.6.0 on Ubuntu 14.04 64bit.
>>>>>
>>>>> Any ideas on this ?
>>>>>
>>>>>
>>>>>
>>>>
>>>
>>
>

Mime
View raw message