Hive and HCatalog require a database to use as a metadata store. MySQL 5.x or Oracle 11gr2 are supported. You may provide access to an existing database, or the Ambari and gsInstaller installers will install MySQL for you if you want.
Oozie requires a database to use as a metadata store, but comes with embedded Derby database by default. MySQL 5.x or Oracle 11gr2 are also supported.
Ambari requires a database to use as a metadata store, but comes with Postgres 8.x. This is the only database supported in this version.
