Configure the CData JDBC Driver for HDFS in a Connection Pool in Tomcat

The CData JDBC Drivers support standard JDBC interfaces to integrate with Web applications running on the JVM. This article details how to connect to HDFS data from a connection pool in Tomcat.

Connect to HDFS Data through a Connection Pool in Tomcat

1. Copy the CData JAR and CData .lic file to $CATALINA_HOME/lib. The CData JAR is located in the lib subfolder of the installation directory.
2. Add a definition of the resource to the context. Specify the JDBC URL here.

   In order to authenticate, set the following connection properties:

   • Host: Set this value to the host of your HDFS installation.
   • Port: Set this value to the port of your HDFS installation. Default port: 50070

   Built-in Connection String Designer

   For assistance in constructing the JDBC URL, use the connection string designer built into the HDFS JDBC Driver. Either double-click the JAR file or execute the jar file from the command-line.

   java -jar cdata.jdbc.hdfs.jar

   Fill in the connection properties and copy the connection string to the clipboard.

   You can see the JDBC URL specified in the resource definition below.

   <Resource name="jdbc/hdfs" auth="Container" type="javax.sql.DataSource" driverClassName="cdata.jdbc.hdfs.HDFSDriver" factory="org.apache.tomcat.jdbc.pool.DataSourceFactory" url="jdbc:hdfs:Host=sandbox-hdp.hortonworks.com;Port=50070;Path=/user/root;User=root;" maxActive="20" maxIdle="10" maxWait="-1" />

   To allow a single application to access HDFS data, add the code above to the context.xml in the application's META-INF directory.

   For a shared resource configuration, add the code above to the context.xml located in $CATALINA_BASE/conf. A shared resource configuration provides connectivity to HDFS for all applications.

3. Add a reference to the resource to the web.xml for the application. HDFS data JSP jdbc/HDFS javax.sql.DataSource Container
4. Initialize connections from the connection pool: Context initContext = new InitialContext(); Context envContext = (Context)initContext.lookup("java:/comp/env"); DataSource ds = (DataSource)envContext.lookup("jdbc/HDFS"); Connection conn = ds.getConnection();

More Tomcat Integration

The steps above show how to connect to HDFS data in a simple connection pooling scenario. For more use cases and information, see the JNDI Datasource How-To in the Tomcat documentation.