The Hive Metastore (HMS) is a repository of metadata for Hive tables and partitions in a relational database, and provides clients (including Hive, Impala and Spark) access to this information using the metastore service API. So when you create a Hive table, the table definition (column names, data types, and comments) is automatically stored in the HMS, and the HMS acts as a central schema repository that can be used by other CDH services like Spark.

Continue reading:

• Configuring HMS in CDH
• Using & Managing HMS in CDH