The recommended front-end module is mod_cluster but mod_jk or mod_proxy could be used as in Tomcat or other AS version.

To use AJP define a ajp connector in the web subsystem like:

<subsystem xmlns="urn:jboss:domain:web:1.0">
            <connector name="http" protocol="HTTP/1.1" socket-binding="http"/>
            <connector name="ajp" protocol="AJP/1.3" socket-binding="ajp"/>

Note: Don't use scheme="ajp" wiith ajp connectors because scheme is used for the redirects

To the ajp in the in the socket-binding-group like:

<socket-binding-group name="standard-sockets" default-interface="public">
         ....
           <socket-binding name="http" port="8080"/>
           <socket-binding name="ajp" port="8009"/>
           <socket-binding name="https" port="8443"/>