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MapReduce job over HBase fails

bhushan.kandalkar
Hi,

I am running MapReduce job over HBase cluster of 3 machines  but it gives me error as Null pointer exception. Caused by ReverseDNS.

When I tried to run MapReduce job over Hadoop it gets executed perfectly.

How to resolve it?

Thanks in advance.
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Re: MapReduce job over HBase fails

Ted Yu-3
What version of HBase are you using ?

Take a look at HBASE-7693 which may apply in your case.

Cheers

On Wed, Feb 20, 2013 at 2:26 AM, bhushan.kandalkar <
[hidden email]> wrote:

> Hi,
>
> I am running MapReduce job over HBase cluster of 3 machines  but it gives
> me
> error as Null pointer exception. Caused by ReverseDNS.
>
> When I tried to run MapReduce job over Hadoop it gets executed perfectly.
>
> How to resolve it?
>
> Thanks in advance.
>
>
>
> --
> View this message in context:
> http://apache-hbase.679495.n3.nabble.com/MapReduce-job-over-HBase-fails-tp4038768.html
> Sent from the HBase User mailing list archive at Nabble.com.
>
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Re: MapReduce job over HBase fails

shashwat shriparv
In reply to this post by bhushan.kandalkar
On Wed, Feb 20, 2013 at 3:56 PM, bhushan.kandalkar <
[hidden email]> wrote:

> How to resolve it?


Your hbase is not able to connect to hbase and its not able to find the
hadoop jars, define hadoop home properly and hadoop lass path




Shashwat Shriparv
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RE: MapReduce job over HBase fails

jack
In reply to this post by bhushan.kandalkar
Construct DNS server and set DNS server



________________________________
 寄件者: bhushan.kandalkar <[hidden email]>
收件者: [hidden email]
寄件日期: 2013/2/20 (週三) 6:26 PM
主旨: MapReduce job over HBase fails
 
Hi,

I am running MapReduce job over HBase cluster of 3 machines  but it gives me
error as Null pointer exception. Caused by ReverseDNS.

When I tried to run MapReduce job over Hadoop it gets executed perfectly.

How to resolve it?

Thanks in advance.



--
View this message in context: http://apache-hbase.679495.n3.nabble.com/MapReduce-job-over-HBase-fails-tp4038768.html
Sent from the HBase User mailing list archive at Nabble.com.
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Re: MapReduce job over HBase fails

bhushan.kandalkar
In reply to this post by Ted Yu-3
Thanks Ted.

I am using Hadoop-1.0.3 and HBase-0.94.3. Is MapReduce job runs over this configuration?
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Re: MapReduce job over HBase fails

Nick Dimiduk
Hi Bhushan,

Yes, MapReduce is supported over HBase for all releases in recent memory.

Please provide the relevant stacktrace of the error you're seeing. How are
you interacting with HBase from MapReduce -- for online reading, writing, I
recommend you make use of TableMapper, TableReducer. Be sure to configure
your job using TableMapReduceUtil. All of these classes, along with
examples of writing MapReduce jobs against HBase, are shipped in the
org.apache.hadoop.hbase.mapreduce package.

Are you able to interact with HBase via the shell (create table, put,
scan)? Be sure you've satisfied the prerequisites [0] for running HBase.
Specifically, I suspect DNS [1] and loopback [2] configuration
are pertinent.

Thanks,
Nick

[0]: http://hbase.apache.org/book.html#basic.prerequisites
[1]: http://hbase.apache.org/book.html#dns
[2]: http://hbase.apache.org/book.html#loopback.ip

On Sun, Feb 24, 2013 at 8:57 PM, bhushan.kandalkar <
[hidden email]> wrote:

> Thanks Ted.
>
> I am using Hadoop-1.0.3 and HBase-0.94.3. Is MapReduce job runs over this
> configuration?
>
>
>
> --
> View this message in context:
> http://apache-hbase.679495.n3.nabble.com/MapReduce-job-over-HBase-fails-tp4038768p4039083.html
> Sent from the HBase User mailing list archive at Nabble.com.
>
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Re: MapReduce job over HBase fails

bhushan.kandalkar
Hi Nick,

Error log:

Exception in thread "main" java.lang.NullPointerException
at org.apache.hadoop.net.DNS.reverseDns(DNS.java:72)
at org.apache.hadoop.hbase.mapreduce.TableInputFormatBase.reverseDNS(TableInputFormatBase.java:218)
at org.apache.hadoop.hbase.mapreduce.TableInputFormatBase.getSplits(TableInputFormatBase.java:183)
at org.apache.hadoop.mapred.JobClient.writeNewSplits(JobClient.java:962)
at org.apache.hadoop.mapred.JobClient.writeSplits(JobClient.java:979)
at org.apache.hadoop.mapred.JobClient.access$600(JobClient.java:174)
at org.apache.hadoop.mapred.JobClient$2.run(JobClient.java:897)
at org.apache.hadoop.mapred.JobClient$2.run(JobClient.java:850)
at java.security.AccessController.doPrivileged(Native Method)
at javax.security.auth.Subject.doAs(Subject.java:416)
at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1121)
at org.apache.hadoop.mapred.JobClient.submitJobInternal(JobClient.java:850)
at org.apache.hadoop.mapreduce.Job.submit(Job.java:500)
at org.apache.hadoop.mapreduce.Job.waitForCompletion(Job.java:530)
at org.apache.hadoop.hbase.mapreduce.CopyTable.main(CopyTable.java:237)


How to resolve it? Is it related to HBASE-7693?


Thanks,

Bhushan

On Wed 27/02/13 1:26 AM , "Nick Dimiduk [via Apache HBase]" ml-node [hidden email] sent:
To: ml-node [hidden email]
Hi Bhushan,

Yes, MapReduce is supported over HBase for all releases in recent memory.

Please provide the relevant stacktrace of the error you're seeing. How are
you interacting with HBase from MapReduce -- for online reading, writing, I
recommend you make use of TableMapper, TableReducer. Be sure to configure
your job using TableMapReduceUtil. All of these classes, along with
examples of writing MapReduce jobs against HBase, are shipped in the
org.apache.hadoop.hbase.mapreduce package.

Are you able to interact with HBase via the shell (create table, put,
scan)? Be sure you've satisfied the prerequisites [0] for running HBase.
Specifically, I suspect DNS [1] and loopback [2] configuration
are pertinent.

Thanks,
Nick

[0]: http://hbase.apache.org/book.html#basic.prerequisites
[1]: http://hbase.apache.org/book.html#dns
[2]: http://hbase.apache.org/book.html#loopback.ip

On Sun, Feb 24, 2013 at 8:57 PM, bhushan.kandalkar <
[hidden email]> wrote:

> Thanks Ted.
>
> I am using Hadoop-1.0.3 and HBase-0.94.3. Is MapReduce job runs over this
> configuration?
>
>
>
> --
> View this message in context:
> http://apache-hbase.679495.n3.nabble.com/MapReduce-job-over-HBase-fails-tp4038768p4039083.html
> Sent from the HBase User mailing list archive at Nabble.com.
>



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Re: MapReduce job over HBase fails

bhushan.kandalkar
In reply to this post by Nick Dimiduk
Hi Nick,

Error log:

Exception in thread "main" java.lang.NullPointerException
at org.apache.hadoop.net.DNS.reverseDns(DNS.java:72)
at org.apache.hadoop.hbase.mapreduce.TableInputFormatBase.reverseDNS(TableInputFormatBase.java:218)
at org.apache.hadoop.hbase.mapreduce.TableInputFormatBase.getSplits(TableInputFormatBase.java:183)
at org.apache.hadoop.mapred.JobClient.writeNewSplits(JobClient.java:962)
at org.apache.hadoop.mapred.JobClient.writeSplits(JobClient.java:979)
at org.apache.hadoop.mapred.JobClient.access$600(JobClient.java:174)
at org.apache.hadoop.mapred.JobClient$2.run(JobClient.java:897)
at org.apache.hadoop.mapred.JobClient$2.run(JobClient.java:850)
at java.security.AccessController.doPrivileged(Native Method)
at javax.security.auth.Subject.doAs(Subject.java:416)
at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1121)
at org.apache.hadoop.mapred.JobClient.submitJobInternal(JobClient.java:850)
at org.apache.hadoop.mapreduce.Job.submit(Job.java:500)
at org.apache.hadoop.mapreduce.Job.waitForCompletion(Job.java:530)
at org.apache.hadoop.hbase.mapreduce.CopyTable.main(CopyTable.java:237)


How to resolve it? Is it related to HBASE-7693?


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