Mapreduce job stuck at map 0% reduce 0% 1


Error Scenario:

Mapreduce job stuck at map 0% reduce 0%. : Could not resolve hostname

Mapreduce jobs are not running. And the below error message is coming when starting HDFS daemons.

Resolution:

These above error messages are received when there is some issue with ssh communication. So, in these situations, we need to remove openssh-client and openssh-server and re-install them again.

Once the ssh is re-installed, we will not get Could not resolve hostname error message while starting hadoop daemons. And ssh communication will not be any more problem, so mapreduce job will start running smoothly.


About Siva

Senior Hadoop developer with 4 years of experience in designing and architecture solutions for the Big Data domain and has been involved with several complex engagements. Technical strengths include Hadoop, YARN, Mapreduce, Hive, Sqoop, Flume, Pig, HBase, Phoenix, Oozie, Falcon, Kafka, Storm, Spark, MySQL and Java.


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Review Comments
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I have attended Siva’s Spark and Scala training. He is good in presentation skills and explaining technical concepts easily to everyone in the group. He is having excellent real time experience and provided enough use cases to understand each concepts. Duration of the course and time management is awesome. Happy that I found a right person on time to learn Spark. Thanks Siva!!!

Dharmeswaran ETL / Hadoop Developer Spark Nov 2016 September 21, 2017

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