JDV Cloudera/Impala Module

Background

JBoss EAP modules allows you to create a shared library that can be referenced by the platform, by any deployed application. This is a good way to reduce code duplication if you have multiple applications bringing their own copy of a library. This is also a good way to make sure every deployment is using a consistent version of a library. A good use-case is when working with databases, and all your applications need a JDBC Driver.

It’s typically pretty easy to set up. You just add a folder to $JBOSS_HOME/modules, create a module.xml file, drop in your jar(s) and call it a day. Doing so for Cloudera’s Impala drivers took a little more work than usual though. This is what I had to do to get it to work on JDV 6.4, which should work on JBoss EAP as well.

Configuration

First, create your folder structure to in $JBOSS_HOME/modules. I like to stay out of the “systems” directory as that folder’s what comes with EAP out-of-the box. It’s just my preference to keep any of my customization in a separate area so that I don’t accidentally break anything.

I created this file $JBOSS_HOME/modules/org.apache.hadoop.impala/module.xml with the following content.

<?xml version="1.0" encoding="UTF-8"?>
<module xmlns="urn:jboss:module:1.0" name="org.apache.hadoop.impala">
    <resources>
      <resource-root path="ImpalaJDBC41.jar"/>
      <resource-root path="hive_metastore.jar"/>
      <resource-root path="hive_service.jar"/>
      <resource-root path="libfb303-0.9.0.jar"/>
      <resource-root path="libthrift-0.9.0.jar"/>
      <resource-root path="TCLIServiceClient.jar"/>
    </resources>
 
    <dependencies>
        <module name="org.apache.log4j"/>
        <module name="org.slf4j"/>
        <module name="org.apache.commons.logging"/>
        <module name="javax.api"/>
        <module name="javax.resource.api"/>        
    </dependencies>
</module>

The Impala JDBC driver had a lot of dependencies, as you can see above. I found most of this out by read through their documentation, and a lot of trial and error.

Once your module is setup, you’ll need to add this driver into the “drivers” section of your configuration file. This is either standalone.xml or domain.xml - based on what mode you’re running. This is pretty standard JBoss configuration at this point, so you should be able to take it from here.

<datasources>
  ...
  <drivers>
    <driver name="impala" module="org.apache.hadoop.impala">
        <driver-class>com.cloudera.impala.jdbc41.Driver</driver-class>
    </driver>
  </drivers>
</datasources>