I wanted to use mysql XA-Datasource to connect mysql datasources using the Wildfly 10 server. XA Datasources are better as it can span multiple resources.

Create the folder structure as /modules/system/layers/base/com/sql/mysql/main

Then create a file as module.xml in the main folder containing following data

<?xml version="1.0" encoding="UTF-8"?>
<module xmlns="urn:jboss:module:1.3" name="com.sql.mysql">
  <resources>
     <resource-root path="mysql-connector-java-5.1.41-bin.jar"/>
  </resources>
  <dependencies>
    <module name="javax.api"/>
    <module name="javax.servlet.api" optional="true"/>
    <module name="javax.validation.api"/>
    <module name="javax.transaction.api"/>
  </dependencies>
</module>

Then copy the MySQL JDBC connector to the folder. The latest version that I had was mysql-connector-java-5.1.41-bin.jar. Change the name in module.xml accordingly.

Download: https://dev.mysql.com/downloads/connector/j/

(note: modify the xml resource-root according to the latest version of the connector jar )

Then go to the standalone/configuration folder and edit standalone.xml. Include following in the datasource part of the xml.

<datasources>
               <xa-datasource jndi-name="java:jboss/datasources/madeinsl" pool-name="madeinsl" enabled="true" use-java-context="true">
                   <xa-datasource-property name="ServerName">
                       localhost
                   </xa-datasource-property>
                   <xa-datasource-property name="DatabaseName">
                       dbname
                   </xa-datasource-property>
                   <driver>mysql</driver>
                   <security>
                       <user-name>root</user-name>
                       <password>password</password>
                   </security>
                   <statement>
                       <prepared-statement-cache-size>100</prepared-statement-cache-size>
                       <share-prepared-statements>true</share-prepared-statements>
                   </statement>
               </xa-datasource>
               <drivers>
                   <driver name="mysql" module="com.sql.mysql">
                       <xa-datasource-class>com.mysql.jdbc.jdbc2.optional.MysqlXADataSource</xa-datasource-class>
                   </driver>
               </drivers>
           </datasources>