Don't pull registry image from private registry

This avoids a potential circular dependency where the registry is the
source of its own image.

Also fixes up the image building documentation about the default value
of kolla_docker_registry.

Change-Id: Ia30173abf185329098ace621baf0ad1be75c0b74
Story: 2004820
Task: 29345

ansible/roles/docker-registry/defaults/main.yml

@@ -39,7 +39,7 @@ docker_registry_port: 5000
 # NOTE: Namespace 'library' causes image task to always be changed and
 # container to never update to new images.
 docker_registry_namespace: ""
-docker_registry_image: "{{ docker_registry ~ '/' if docker_registry | default else '' }}{{ docker_registry_namespace ~ '/' if docker_registry_namespace else '' }}registry"
+docker_registry_image: "{{ docker_registry_namespace ~ '/' if docker_registry_namespace else '' }}registry"
 docker_registry_tag: "latest"
 docker_registry_image_full: "{{ docker_registry_image }}:{{ docker_registry_tag }}"
 

doc/source/configuration/hosts.rst

@@ -509,6 +509,8 @@ Kolla-ansible Remote Virtual Environment
 See :ref:`configuration-kolla-ansible-venv` for information about remote Python
 virtual environments for Kolla Ansible.
 
+.. _configuration-hosts-docker:
+
 Docker Engine
 =============
 

doc/source/configuration/kolla.rst

@@ -75,8 +75,8 @@ used to generate the Kolla configuration file, ``kolla-build.conf``.
 ``kolla_docker_namespace``
     Docker namespace to use for Kolla images. Default is ``kolla``.
 ``kolla_docker_registry``
-    URL of docker registry to use for Kolla images. Default is not set, in
-    which case Dockerhub will be used.
+    URL of docker registry to use for Kolla images. Default is to use the value
+    of ``docker_registry`` variable (see :ref:`configuration-hosts-docker`).
 ``kolla_docker_registry_username``
     Username to use to access a docker registry. Default is not set, in which
     case the registry will be used without authentication.

releasenotes/notes/docker-registry-on-seed-2eb4fb643d6fda9a.yaml

@@ -7,3 +7,7 @@ upgrade:
     the seed group from ``[docker-registry:children]`` in
     ``$KAYOBE_CONFIG_PATH/inventory/groups` and creating a
     ``[docker-registry]`` group including the name of the first controller.
+  - |
+    Modifies the default value of ``docker_registry_image`` variable to not use
+    a private registry in the image name by default. This avoids a potential
+    circular dependency during deployment of the registry container.