Add insecure registries to dockerd: simple etc file

[Théo Tyburn]

Hi guix,

I am trying to add some registries to dockerd. It seems it is not
possible to do this via environment variable, so I can't just modify the
configuration of docker-service-type. The standard way to add insecure
registries is via /etc/docker/daemon.json.

So I tried adding
(simple-service 'docker-insecure-registries etc-service-type
                      `(("docker/daemon.json" ,(plain-file "docker-daemon.json"
                                                                                
                                   
"{\"insecure-registries\":[\"myserver:5000\"}"))))
But I get `guix system: error: symlink: File exists: "/etc/docker"`

If I make "docker/daemon.json" to "/docker/daemon.json" the build fails
and the logs say: `ice-9/eval.scm:619:8: In procedure mkdir: Permission
denied`

How can I add this etc file in the docker directory ?

Cheers,

Théo