Apache Spark-Apache Hive connection configuration

You need to understand the workflow and service changes involved in accessing ACID table data from Spark. You can configure Spark properties in Ambari for using the Hive Warehouse Connector.

Prerequisites

The Hive connection string must include a user name and password; otherwise, Spark and Hive cannot connect. For example:

jdbc:hive2://<host>:2181;serviceDiscoveryMode=zooKeeper;zooKeeperNamespace=hiveserver2-interactive;user=<user name>;password=<password>

You need to use the following software to connect Spark and Hive using the HiveWarehouseConnector library.

HDP 3.0 or later
Spark2

Hive with HiveServer Interactive (HSI)

The Hive Warehouse Connector (HWC) and low-latency analytical processing (LLAP) are required for certain tasks, as shown in the following table:

Table 1. Spark Compatibility
Tasks	HWC Required	LLAP Required	Other Requirement/Comments
Read Hive managed tables from Spark	Yes	Yes	Ranger ACLs enforced.*
Write Hive managed tables from Spark	Yes	N/A	Ranger ACLs enforced.*
Read Hive external tables from Spark	No	N/A unless HWC is used, then LLAP is required	Table must be defined in Spark catalog. Ranger ACLs not enforced.
Write Hive external tables from Spark	No	N/A	Ranger ACLs enforced.

* Ranger column level security or column masking is supported for each access pattern when you use HWC.

You need low-latency analytical processing (LLAP) in HSI to read ACID, or other Hive-managed tables, from Spark. You do not need LLAP to write to ACID, or other managed tables, from Spark. The HWC library internally uses the Hive Streaming API and LOAD DATA Hive commands to write the data. You do not need LLAP to access external tables from Spark with caveats shown in the table above.

Required properties

You must add several Spark properties through spark-2-defaults in Ambari to use the Hive Warehouse Connector for accessing data in Hive. Alternatively, configuration can be provided for each job using --conf.

spark.sql.hive.hiveserver2.jdbc.url
The URL for HiveServer2 Interactive
spark.datasource.hive.warehouse.metastoreUri
The URI for the metastore
spark.datasource.hive.warehouse.load.staging.dir
The HDFS temp directory for batch writes to Hive, /tmp for example
spark.hadoop.hive.llap.daemon.service.hosts
The application name for LLAP service
spark.hadoop.hive.zookeeper.quorum
The ZooKeeper hosts used by LLAP

Set the values of these properties as follows:

spark.sql.hive.hiveserver2.jdbc.url
In Ambari, copy the value from Services > Hive > Summary > HIVESERVER2 INTERACTIVE JDBC URL.
spark.datasource.hive.warehouse.metastoreUri
Copy the value from hive.metastore.uris. In Hive, at the hive> prompt, enter set hive.metastore.uris and copy the output. For example, thrift://mycluster-1.com:9083.
spark.hadoop.hive.llap.daemon.service.hosts
Copy value from Advanced hive-interactive-site > hive.llap.daemon.service.hosts.
spark.hadoop.hive.zookeeper.quorum
Copy the value from Advanced hive-sitehive.zookeeper.quorum.

Other HWC properties

The spark.datasource.hive.warehouse.write.path.strictColumnNamesMapping validates the mapping of columns against those in Hive to alert the user to input errors. Default = true.

Spark on a Kerberized YARN cluster

In Spark client mode on a kerberized Yarn cluster, set the following property: spark.sql.hive.hiveserver2.jdbc.url.principal. This property must be equal to hive.server2.authentication.kerberos.principal. In Ambari, copy the value for this property from Services > Hive > Configs > Advanced > Advanced hive-site hive.server2.authentication.kerberos.principal.