At the moment there is no feature to automatic distribute modules in a domain, you need to install it on each host.
If you configure an application with dependencies (you can use MANIFEST or jboss-deployment-structure) you need to have the module installed first.
Otherwise a deploy will fail.
The domain is 'only' a administrative instance to handle multiple servers on different host-contollers.
I hope that the feature to distribute modules is added soon to make this administration more simple.
Thanks for your answer.
I'll keep a close watch to the updates.