Configuring the Hive Metastore for CDH

Cloudera recommends you configure a database for the metastore on one or more remote servers that reside on a host or hosts separate from the HiveServer2 process. MySQL is the most popular database to use. Use the following steps to configure a remote metastore. If you are planning to use a cloud service database, such as Amazon Relational Database Service (RDS), see Configuring a Shared Amazon RDS as an HMS for CDH for information about how to set up a shared Amazon RDS as your Hive metastore.

1. Install and start MySQL if you have not already done so
   To install MySQL on a RHEL system:

   sudo yum install mysql-server

   To install MySQL on a SLES system:

   sudo zypper install mysql
   sudo zypper install libmysqlclient_r17

   To install MySQL on a Debian/Ubuntu system:

   sudo apt-get install mysql-server

   After using the command to install MySQL, you may need to respond to prompts to confirm that you do want to complete the installation. After installation completes, start the mysql daemon.
   On RHEL systems

   sudo service mysqld start

   On SLES and Debian/Ubuntu systems

   sudo service mysql start

2. Configure the MySQL service and JDBC driver

   Before you can run the Hive metastore with a remote MySQL database, you must install the MySQL JDBC driver, set up the initial database schema, and configure the MySQL user account for the Hive user.

   For instructions on installing the MySQL JDBC driver, see Installing the MySQL JDBC Driver.

   Configure MySQL to use a strong password and to start at boot. Note that in the following procedure, your current root password is blank. Press the Enter key when you're prompted for the root password.

   To set the MySQL root password:

   $ sudo /usr/bin/mysql_secure_installation
   [...]
   Enter current password for root (enter for none):
   OK, successfully used password, moving on...
   [...]
   Set root password? [Y/n] y
   New password:
   Re-enter new password:
   Remove anonymous users? [Y/n] Y
   [...]
   Disallow root login remotely? [Y/n] N
   [...]
   Remove test database and access to it [Y/n] Y
   [...]
   Reload privilege tables now? [Y/n] Y
   All done!

   To make sure the MySQL server starts at boot:

   • On RHEL systems:

   $ sudo /sbin/chkconfig mysqld on
   sudo /sbin/chkconfig --list mysqld
   mysqld          0:off   1:off   2:on    3:on    4:on    5:on    6:off

   • On SLES systems:

   sudo chkconfig --add mysql

   • On Debian/Ubuntu systems:

   sudo chkconfig mysql on

3. Create the database and user

   The instructions in this section assume you are using Remote mode, and that the MySQL database is installed on a separate host from the metastore service, which is running on a host named metastorehost in the example.

   Create the initial database schema. Cloudera recommends using the Metastore Schema Tool to do this.

   If for some reason you decide not to use the schema tool, you can use the hive-schema-n.n.n.mysql.sql file instead; that file is located in the /usr/lib/hive/scripts/metastore/upgrade/mysql/ directory. (n.n.n is the current Hive version, for example 1.1.0.) Proceed as follows if you decide to use hive-schema-n.n.n.mysql.sql.

   Example using hive-schema-n.n.nmysql.sql

   $ mysql -u root -p
   Enter password:
   mysql> CREATE DATABASE metastore;
   mysql> USE metastore;
   mysql> SOURCE /usr/lib/hive/scripts/metastore/upgrade/mysql/hive-schema-n.n.n.mysql.sql;

   You also need a MySQL user account for Hive to use to access the metastore. It is very important to prevent this user account from creating or altering tables in the metastore database schema.

   Example

   mysql> CREATE USER 'hive'@'metastorehost' IDENTIFIED BY 'mypassword';
   ...
   mysql> REVOKE ALL PRIVILEGES, GRANT OPTION FROM 'hive'@'metastorehost';
   mysql> GRANT ALL PRIVILEGES ON metastore.* TO 'hive'@'metastorehost';
   mysql> FLUSH PRIVILEGES;
   mysql> quit;

4. Configure the metastore service to communicate with the MySQL database

   This step shows the configuration properties you need to set in hive-site.xml (/usr/lib/hive/conf/hive-site.xml) to configure the metastore service to communicate with the MySQL database, and provides sample settings. Though you can use the same hive-site.xml on all hosts (client, metastore, HiveServer2), hive.metastore.uris is the only property that must be configured on all of them; the others are used only on the metastore host.

   Given a MySQL database running on myhost and the user account hive with the password mypassword, set the configuration as follows (overwriting any existing values).

   <property>
     <name>javax.jdo.option.ConnectionURL</name>
     <value>jdbc:mysql://myhost/metastore</value>
     <description>the URL of the MySQL database</description>
   </property>
   
   <property>
     <name>javax.jdo.option.ConnectionDriverName</name>
     <value>com.mysql.jdbc.Driver</value>
   </property>
   
   <property>
     <name>javax.jdo.option.ConnectionUserName</name>
     <value>hive</value>
   </property>
   
   <property>
     <name>javax.jdo.option.ConnectionPassword</name>
     <value>mypassword</value>
   </property>
   
   <property>
     <name>datanucleus.autoCreateSchema</name>
     <value>false</value>
   </property>
   
   <property>
     <name>datanucleus.fixedDatastore</name>
     <value>true</value>
   </property>
   
   <property>
     <name>datanucleus.autoStartMechanism</name> 
     <value>SchemaTable</value>
   </property> 
   
   <property>
     <name>hive.metastore.uris</name>
     <value>thrift://<n.n.n.n>:9083</value>
     <description>IP address (or fully-qualified domain name) and port of the metastore host</description>
   </property>
   
   <property>
   <name>hive.metastore.schema.verification</name>
   <value>true</value>
   </property>

Before you can run the Hive metastore with a remote PostgreSQL database, you must configure a connector to the remote PostgreSQL database, set up the initial database schema, and configure the PostgreSQL user account for the Hive user.

1. Install and start PostgreSQL if you have not already done so

   To install PostgreSQL on a RHEL system:

   sudo yum install postgresql-server

   To install PostgreSQL on a SLES system:

   sudo zypper install postgresql-server

   To install PostgreSQL on a Debian/Ubuntu system:

   sudo apt-get install postgresql

   After using the command to install PostgreSQL, you may need to respond to prompts to confirm that you do want to complete the installation. In order to finish installation on RHEL compatible systems, you need to initialize the database. Please note that this operation is not needed on Ubuntu and SLES systems as it's done automatically on first start:

   To initialize database files on RHEL compatible systems

   sudo service postgresql initdb

   To ensure that your PostgreSQL server will be accessible over the network, you need to do some additional configuration.

   First you need to edit the postgresql.conf file. Set the listen_addresses property to *, to make sure that the PostgreSQL server starts listening on all your network interfaces. Also make sure that the standard_conforming_strings property is set to off.

   You can check that you have the correct values as follows:

   On Red-Hat-compatible systems:

   $ sudo cat /var/lib/pgsql/data/postgresql.conf  | grep -e listen -e standard_conforming_strings
   listen_addresses = '*'
   standard_conforming_strings = off

   On SLES systems:

   $ sudo cat /var/lib/pgsql/data/postgresql.conf  | grep -e listen -e standard_conforming_strings
   listen_addresses = '*'
   standard_conforming_strings = off

   On Ubuntu and Debian systems:

   $ cat /etc/postgresql/9.1/main/postgresql.conf | grep -e listen -e standard_conforming_strings
   listen_addresses = '*'
   standard_conforming_strings = off

   You also need to configure authentication for your network in pg_hba.conf. You need to make sure that the PostgreSQL user that you will create later in this procedure will have access to the server from a remote host. To do this, add a new line into pg_hba.con that has the following information:

   host    <database>         <user>         <network address>         <mask>               md5

   The following example allows all users to connect from all hosts to all your databases:

   host    all         all         0.0.0.0         0.0.0.0               md5

   After completing the installation and configuration, you can start the database server:

   Start PostgreSQL Server

   sudo service postgresql start

   Use chkconfig utility to ensure that your PostgreSQL server will start at a boot time. For example:

   chkconfig postgresql on

   You can use the chkconfig utility to verify that PostgreSQL server will be started at boot time, for example:

   chkconfig --list postgresql

2. Install the PostgreSQL JDBC driver

   Before you can run the Hive metastore with a remote PostgreSQL database, you must configure a JDBC driver to the remote PostgreSQL database, set up the initial database schema, and configure the PostgreSQL user account for the Hive user.

   To install the PostgreSQL JDBC Driver on a RHEL 6 system:

   On the Hive metastore server host, install postgresql-jdbc package and create symbolic link to the /usr/lib/hive/lib/ directory. For example:

   sudo yum install postgresql-jdbc
   ln -s /usr/share/java/postgresql-jdbc.jar /usr/lib/hive/lib/postgresql-jdbc.jar

   To install the PostgreSQL JDBC Driver on a SLES system:

   On the Hive metastore server host, install postgresql-jdbc and symbolically link the file into the /usr/lib/hive/lib/ directory.

   $ sudo zypper install postgresql-jdbc
   $ ln -s /usr/share/java/postgresql-jdbc.jar
   /usr/lib/hive/lib/postgresql-jdbc.jar

   To install the PostgreSQL JDBC Driver on a Debian/Ubuntu system:

   On the Hive metastore server host, install libpostgresql-jdbc-java and symbolically link the file into the /usr/lib/hive/lib/ directory.

   sudo apt-get install libpostgresql-jdbc-java
   ln -s /usr/share/java/postgresql-jdbc4.jar /usr/lib/hive/lib/postgresql-jdbc4.jar

3. Create the metastore database and user account

   Proceed as in the following example, using the appropriate script in /usr/lib/hive/scripts/metastore/upgrade/postgres/ n.n.n is the current Hive version, for example 1.1.0:

   $ sudo -u postgres psql
   postgres=# CREATE USER hiveuser WITH PASSWORD 'mypassword';
   postgres=# CREATE DATABASE metastore;
   postgres=# \c metastore;
   You are now connected to database 'metastore'.
   postgres=# \i /usr/lib/hive/scripts/metastore/upgrade/postgres/hive-schema-n.n.n.postgres.sql
   SET
   SET
   ...

   Now you need to grant permission for all metastore tables to user hiveuser. PostgreSQL does not have statements to grant the permissions for all tables at once; you'll need to grant the permissions one table at a time. You could automate the task with the following SQL script:

   bash# sudo -u postgres psql
   metastore=# \c metastore
   metastore=# \pset tuples_only on
   metastore=# \o /tmp/grant-privs
   metastore=#   SELECT 'GRANT SELECT,INSERT,UPDATE,DELETE ON "'  || schemaname || '". "' ||tablename ||'" TO hiveuser ;'
   metastore-#   FROM pg_tables
   metastore-#   WHERE tableowner = CURRENT_USER and schemaname = 'public';
   metastore=# \o
   metastore=# \pset tuples_only off
   metastore=# \i /tmp/grant-privs

   You can verify the connection from the machine where you'll be running the metastore service as follows:

   psql -h myhost -U hiveuser -d metastore
   metastore=#

4. Configure the metastore service to communicate with the PostgreSQL database

   This step shows the configuration properties you need to set in hive-site.xml (/usr/lib/hive/conf/hive-site.xml) to configure the metastore service to communicate with the PostgreSQL database. Though you can use the same hive-site.xml on all hosts (client, metastore, HiveServer2), hive.metastore.uris is the only property that must be configured on all of them; the others are used only on the metastore host.

   Given a PostgreSQL database running on host myhost under the user account hive with the password mypassword, you would set configuration properties as follows.

   <property>
     <name>javax.jdo.option.ConnectionURL</name>
     <value>jdbc:postgresql://myhost/metastore</value>
   </property>
    
   <property>
     <name>javax.jdo.option.ConnectionDriverName</name>
     <value>org.postgresql.Driver</value>
   </property>
    
   <property>
     <name>javax.jdo.option.ConnectionUserName</name>
     <value>hiveuser</value>
   </property>
    
   <property>
     <name>javax.jdo.option.ConnectionPassword</name>
     <value>mypassword</value>
   </property>
    
   <property>
     <name>datanucleus.autoCreateSchema</name>
     <value>false</value>
   </property>
   
   <property>
     <name>hive.metastore.uris</name>
     <value>thrift://<n.n.n.n>:9083</value>
     <description>IP address (or fully-qualified domain name) and port of the metastore host</description>
   </property>
   
   <property>
   <name>hive.metastore.schema.verification</name>
   <value>true</value>
   </property>

5. Test connectivity to the metastore

   hive –e “show tables;”

Before you can run the Hive metastore with a remote Oracle database, you must configure a connector to the remote Oracle database, set up the initial database schema, and configure the Oracle user account for the Hive user.

1. Install and start Oracle

   The Oracle database is not part of any Linux distribution and must be purchased, downloaded and installed separately. You can use the Express edition, which can be downloaded free from the Oracle website.

2. Install the Oracle JDBC Driver

   You must download the Oracle JDBC Driver from the Oracle website and put the JDBC JAR file into the /usr/lib/hive/lib/ directory. For example, the version 6 JAR file is named ojdbc6.jar. To download the JDBC driver, visit the Oracle JDBC and UCP Downloads page, and click on the link for your Oracle Database version. Download the ojdbc6.jar file (or ojdbc8.jar, for Oracle Database 12.2).

   sudo mv ojdbc<version_number>.jar /usr/lib/hive/lib/

3. Create the metastore database and user account

   Connect to your Oracle database as an administrator and create the user that will use the Hive metastore.

   $ sqlplus "sys as sysdba"
   SQL> create user hiveuser identified by mypassword;
   SQL> grant connect to hiveuser;
   SQL> grant all privileges to hiveuser;

   Connect as the newly created hiveuser user and load the initial schema, as in the following example. Use the appropriate script for the current release (for example hive-schema-1.1.0.oracle.sql) in /usr/lib/hive/scripts/metastore/upgrade/oracle/ :

   $ sqlplus hiveuser
   SQL> @/usr/lib/hive/scripts/metastore/upgrade/oracle/hive-schema-n.n.n.oracle.sql

   Connect back as an administrator and remove the power privileges from user hiveuser. Then grant limited access to all the tables:

   $ sqlplus "sys as sysdba"
   SQL> revoke all privileges from hiveuser;
   SQL> BEGIN
     2     FOR R IN (SELECT owner, table_name FROM all_tables WHERE owner='HIVEUSER') LOOP
     3        EXECUTE IMMEDIATE 'grant  SELECT,INSERT,UPDATE,DELETE on '||R.owner||'.'||R.table_name||' to hiveuser';
     4     END LOOP;
     5  END;
     6  
     7  /

4. Configure the metastore service to Communicate with the Oracle Database

   This step shows the configuration properties you need to set in hive-site.xml (/usr/lib/hive/conf/hive-site.xml) to configure the metastore service to communicate with the Oracle database, and provides sample settings. Though you can use the same hive-site.xml on all hosts (client, metastore, HiveServer2), hive.metastore.uris is the only property that must be configured on all of them; the others are used only on the metastore host.

   Example

   Given an Oracle database running on myhost and the user account hiveuser with the password mypassword, set the configuration as follows (overwriting any existing values):

   <property>
     <name>javax.jdo.option.ConnectionURL</name>
     <value>jdbc:oracle:thin:@//myhost/xe</value>
   </property>
    
   <property>
     <name>javax.jdo.option.ConnectionDriverName</name>
     <value>oracle.jdbc.OracleDriver</value>
   </property>
    
   <property>
     <name>javax.jdo.option.ConnectionUserName</name>
     <value>hiveuser</value>
   </property>
    
   <property>
     <name>javax.jdo.option.ConnectionPassword</name>
     <value>mypassword</value>
   </property>
    
   <property>
     <name>datanucleus.autoCreateSchema</name>
     <value>false</value>
   </property>
    
   <property>
     <name>datanucleus.fixedDatastore</name>
     <value>true</value>
   </property>
    
   <property>
     <name>hive.metastore.uris</name>
     <value>thrift://<n.n.n.n>:9083</value>
     <description>IP address (or fully-qualified domain name) and port of the metastore host</description>
   </property>
   
   <property>
   <name>hive.metastore.schema.verification</name>
   <value>true</value>
   </property>

Prerequisites