PIG is an SQL like scripting language that helps users to write data manipulation operations without knowing Java.
Mahout is a distributed linear algebra framework and a library of a scalable machine-learning algorithm.
Hive is a framework for Datawarehousing on top of Hadoop.
Spark is a framework for real-time processing and is written in Scala.
HBase is NoSQL database.
Apache Drill is SQL query engine used for analysis of the big data.
Zookeeper helps in coordinating and managing services in a distributed environment.
Apache Oozie is a scheduler that schedules Hadoop jobs.
Apache Flume is a distributed, reliable and available software used for streaming data.
Apache Sqoop can import and export structured data from RDBMS to HDFS and vice-versa.
Apache Ambari takes care of provisioning, managing, and monitoring Hadoop ecosystem.