Changing docker root directory


I am trying to modify the root directory for Docker within RancherOS - or at the very least modify the container volume paths. I have a FreeNAS box running a docker VM (RancherOS) and within that I have installed Portainer to easily manage the containers. Everything is running perfectly except for the fact that containers are created in /var/lib/docker/volumes . I have a share which I would like to run docker from /mnt/nfs-1/docker .

I have read the docker documentation and people suggest editing the Daemon to update the path - which does not exist on RancherOS. I suspect I need to use sudo ros config to set the paths but I can’t seem to get it to work. Is there a simple way of modifying the root directory?