Update cloud-config


I have some difficulties finding documentation about RancherOS 1.x, in particular, cloud-config and ros. All references I found point to 404.

I have deployed RancherOS with local cloud-config. I am wondering how to update this now. First, does it read the cloud-config file every time it boots so one way to do it would be to have the file availaible through http?

If the file is local like I did, I understand I can export it

ros config export > config.yaml
edit the config locally

and merge?
ros config merge -i config.yaml

I am not sure about merging it. What happens if I remove an rsa-key and add a new one?
How can I add nfs shares and remove others if it merges?

Is there any way to replace the file instead?

I understand that /var/lib/rancher is persistent.
Should I edit /var/lib/rancher/conf/cloud-config.d/user_config.yml directly and reboot then?
Will it re-generates /var/lib/rancher/conf/cloud-config.yml?

Sorry for those naive questions but there is really close to no documentation on those points.

Thank you for your help,