Can't use images from k8s.gcr.io registry in my kubernetes cluster

According to Rancher

"If you want to use Google Container Registry, you will have to use a service account JSON key file. Don’t forget to grant the correct permissions to the Google Cloud Storage bucket containing your Container Registry images.

Specify the registry address according to the region your images are stored. Use _json_key as username and use the full contents of the service account JSON key file as password."