Question 121: What is Zookeeper service?

Answer: A centralized service for maintaining configuration information, naming, and providing distributed synchronization and group services. In a CDH cluster, ZooKeeper coordinates the activities of high-availability services, including HDFS, Oozie, Hive, Solr, YARN, HBase, and Hue.

Question 122: What is a Databricks Delta?

Answer: Databricks delta is a transactional storage layer, which uses the Apache Spark and Databricks Distributed filesystem.