Configuring a Hive Data Connection

This section describes how to switch the Hive metadata of an active cluster to the metadata stored in a local database or RDS database after you create a cluster. This operation enables multiple MRS clusters to share the same metadata, and the metadata will not be deleted when the clusters are deleted. In this way, Hive metadata migration is not required during cluster migration.

When Hive metadata is switched between different clusters, MRS synchronizes only the permissions in the metadata database of the Hive component. The permission model on MRS is maintained on MRS Manager. Therefore, when Hive metadata is switched between clusters, the permissions of users or user groups cannot be automatically synchronized to MRS Manager of another cluster.
For clusters whose version is earlier than MRS 3.x, if the selected data connection is RDS MySQL database, ensure that the database user is root. If the user is not root, create a user and grant permissions to the user by referring to Performing Operations Before Data Connection.
For clusters whose version is MRS 3.x or later, if the selected data connection is RDS MySQL database, the database user cannot be user root. In this case, create a user and grant permissions to the user by following the instructions provided in Performing Operations Before Data Connection.

Configuring a Hive Data Connection

This function is not supported in MRS 3.0.5.

Log in to the MRS console. In the navigation pane on the left, choose Clusters > Active Clusters.
Click the name of a cluster to go to the cluster details page.
On the Dashboard tab page, click Manage next to Data Connection.
On the Data Connection dialog box, the data connections associated with the cluster are displayed. You can click Edit or Delete to edit or delete the data connections.

If there is no associated data connection on the Data Connection dialog box, click Configure Data Connection to add a connection.

Only one data connection can be configured for a module type. For example, after a data connection is configured for Hive metadata, no other data connection can be configured for it. If no module type is available, the Configure Data Connection button is unavailable.

**Table 1** Configuring a Hive data connection
Parameter	Description
Component	Hive
Module Type	Hive metadata
Data Connection Type	RDS MySQL database Local database
Instance	This parameter is valid only when Data Connection Type is set to RDS PostgreSQL database or RDS MySQL database. Select the name of the connection between the MRS cluster and the RDS database. This instance must be created before being referenced here. You can click Create Data Connection to create a data connection. For details, see Creating a Data Connection.

Click Test to test connectivity of the data connection.
After the data connection is successful, click OK.
- After Hive metadata is configured, restart Hive. Hive will create necessary database tables in the specified database. (If tables already exist, they will not be created.)
- Before restarting the Hive service, ensure that the driver package has been installed on all nodes where Metastore instances are located.
  - Postgres: Use the open source Postgres driver package to replace the existing one of the cluster. Upload the Postgres driver package postgresql-42.2.5.jar to the ${BIGDATA_HOME}/third_lib/Hive directory on all MetaStore instance nodes. To download the open-source driver package, visit https://repo1.maven.org/maven2/org/postgresql/postgresql/42.2.5/.
  - MySQL: Go to the MySQL official website (https://www.mysql.com/). Choose DOWNLOADS and click MySQL Community (GPL) Downloads. On the displayed page, click Connector/J to download the driver package of the corresponding version and upload the driver package to the /opt/Bigdata/FusionInsight_HD_*/install/FusionInsight-Hive-*/hive-*/lib/ directory on all RDSMetastore nodes.