How to edit the /etc/docker/daemon.json

[neofusion]

As I replied in the other thread you posted this in:

Allow specify registry-mirrors or proxies in `/etc/docker/daemon.json`

I see two options for you: Either vote for this Feature Request and wait to see if iXsystems accepts it or add a post-init script that edits the file in question post every boot.

You will have to write that post-init script yourself.