Explictly define the pacakge repo filename.

On debian-flavored systems, failure to do this means that ansible will 
generate the filename, and that filename will include many elements of 
the repository, which can include version numbers.  This means that 
after upgrading distribution versions, one will end up with multiple 
repository definitions in separate files.

defaults/main.yml

@@ -20,11 +20,13 @@ docker_repo_url: https://download.docker.com/linux
 docker_apt_release_channel: stable
 docker_apt_arch: amd64
 docker_apt_repository: "deb [arch={{ docker_apt_arch }}] {{ docker_repo_url }}/{{ ansible_distribution | lower }} {{ ansible_distribution_release }} {{ docker_apt_release_channel }}"
+docker_apt_repo_filename: "{{ docker_package }}"
 docker_apt_ignore_key_error: true
 docker_apt_gpg_key: "{{ docker_repo_url }}/{{ ansible_distribution | lower }}/gpg"
 
 # Used only for RedHat/CentOS/Fedora.
 docker_yum_repo_url: "{{ docker_repo_url }}/{{ (ansible_distribution == 'Fedora') | ternary('fedora','centos') }}/docker-{{ docker_edition }}.repo"
+docker_yum_repo_filename: "{{ docker_package }}"
 docker_yum_repo_enable_nightly: '0'
 docker_yum_repo_enable_test: '0'
 docker_yum_gpg_key: "{{ docker_repo_url }}/centos/gpg"

tasks/setup-Debian.yml

@@ -47,5 +47,6 @@
 - name: Add Docker repository.
   apt_repository:
     repo: "{{ docker_apt_repository }}"
+    filename: "{{ docker_apt_repo_filename }}"
     state: present
     update_cache: true

tasks/setup-RedHat.yml

@@ -15,14 +15,14 @@
 - name: Add Docker repository.
   get_url:
     url: "{{ docker_yum_repo_url }}"
-    dest: '/etc/yum.repos.d/docker-{{ docker_edition }}.repo'
+    dest: '/etc/yum.repos.d/{{ docker_yum_repo_filename }}.repo'
     owner: root
     group: root
     mode: 0644
 
 - name: Configure Docker Nightly repo.
   ini_file:
-    dest: '/etc/yum.repos.d/docker-{{ docker_edition }}.repo'
+    dest: '/etc/yum.repos.d/{{ docker_yum_repo_filename }}.repo'
     section: 'docker-{{ docker_edition }}-nightly'
     option: enabled
     value: '{{ docker_yum_repo_enable_nightly }}'
@@ -30,7 +30,7 @@
 
 - name: Configure Docker Test repo.
   ini_file:
-    dest: '/etc/yum.repos.d/docker-{{ docker_edition }}.repo'
+    dest: '/etc/yum.repos.d/{{ docker_yum_repo_filename }}.repo'
     section: 'docker-{{ docker_edition }}-test'
     option: enabled
     value: '{{ docker_yum_repo_enable_test }}'