Hadoop Interview Questions, Answers for Freshers and Experienced asked in various Company Job Interviews

Apache Hadoop (394)
MapReduce (354)
Apache Hive (345)
Apache Pig (225)

Apache Ambari (93)
Apache HCatalog (34)
Apache HDFS Hadoop Distributed File System (214)
Apache Kafka (189)

Hadoop Interview Questions

Questions Answers Views Company eMail

Ideally what should be the block size in hadoop?

492

What happen when namenode enters in safemode in hadoop?

469

What is shuffleing in mapreduce?

694

Does mapreduce programming model provide a way for reducers to communicate with each other? In a mapreduce job can a reducer communicate with another reducer?

721

How would you tackle calculating the number of unique visitors for each hour by mining a huge apache log? You can use post processing on the output of the mapreduce job.

895

Describe what happens to a mapreduce job from submission to output?

721

If reducers do not start before all mappers finish then why does the progress on mapreduce job shows something like map(50%) reduce(10%)? Why reducers progress percentage is displayed when mapper is not finished yet?

759

What are mapreduce new and old apis while writing map reduce program?. Explain how it works

716

Give some points of pig for hadoop ?

588

How does master slave architecture in the hadoop?

879

Explain the wordcount implementation via hadoop framework ?

762

What is hadoop framework?

760

What is partioner in hadoop? Where does it run,mapper or reducer?

708

What is a task instance in hadoop? Where does it run?

656

How to enable recycle bin in hadoop?

798

Un-Answered Questions { Hadoop }

What is the throughput?

How many layers of Hadoop components are supported by Apache Ambari and what are they?

List some benefits of apache kafka?

594

Can multiple clients write into a Hadoop HDFS file concurrently?

Explain how do you overwrite replication factor?

461

Explain bagtostring in pig?

594

What is the primary purpose of flume in the hadoop architecture?

875

What is Hive ?

1042

What do you mean by metadata in HDFS? Where is it stored in Hadoop?

Explain partitions?

292

What do you understand by Consistency in Cassandra?

Explain HCatalog Create Table CLI along with its syntax?

Give some points of hive for hadoop ?

765

Web-ui shows that half of the datanodes are in decommissioning mode. What does that mean? Is it safe to remove those nodes from the network?

484

How is it different from doing machine learning in r or sas?

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