It can be used ro bypass docker-hub & gcr limitations for iranian developers. just run this services on server with access to free internet.

Either pass the --registry-mirror option when starting dockerd manually, or edit /etc/docker/daemon.json and add the registry-mirrors key and value, to make the change persistent.

{
  "registry-mirrors": ["https://<my-docker-mirror-host>"]
}

You must enable https on installation if you want pull images without setting registry-mirrors, for example something like this:

docker pull registry-docker.example.com/curlimages/curl

If you enabled auth credentials on installation you have to login to repository on your machine by executing:

docker login registry-docker.example.com
docker login registry-k8s.example.com
# etc...

./change_auth.sh

• registry-1.docker.io as registry-docker.example.com
• k8s.gcr.io as registry-k8s.example.com
• quay.io as registry-quay.example.com
• gcr.io as registry-gcr.example.com
• ghcr.io as registry-ghcr.example.com

• docker
• docker-compose

# Just run 
./install.sh # it will ask everything needs...

read more : Registry as a pull through cache