What is the use of combiner?

Combine Mapper output Separate Reducer output Separate Mapper input Separate Mapper output

What does JobTracker do

coordinates and schedules the job Stores blocks of data stores metadata acts as a mini reducer

Which component of Hadoop supports web service?

Yarn NameNode MapReduce Load Balancer

Which ecosystem project is ideal for use when we have multiple mapreduce and pig programs to run in a sequence

Oozie Hive Pig Sqoop

What open-source software was developed from Google’s MapReduce concept?

MongoDB Splunk Hadoop Puppet