How to add system.hostfs definition into the yml files

According to https://www.elastic.co/guide/en/beats/metricbeat/current/running-on-docker.html i need to pass on docker containers the "-e -system.hostfs=/hostfs" however is there any way that i can add that to either the system.yml i have on the modules.d folder or to the metricbeat.yml? for my use case it would be ideal.

What would be the correct key to add to those yml if so? i have tried

on metricbeat.yml:
system.hostfs: /hostfs

on system.yml (on modules.d folder):
- module: system
hostfs: /host

Yet none of them seem to work

@micas,

Unfortunately, right now you can only specify hostfs via the command line.