In our HA stuff, we are moving away from the inherits pattern.  Instead, we include the params class we want to use (in our case pacemaker::params) and use a little wrapper function called map_params to do what you try to do in the comment above.  So that may not be needed here, just mentioning that it is available to use.  Foreman will resolve the scope correctly, so you can override in the UI at the hostgroup level, or for a specific host.  So, as an example, if you were using $volume in quickstack::params, you could change line 7 below to:
```
volume => map_params("volume"),
```