kubespray/roles/docker/vars/ubuntu.yml

docker_kernel_min_version: '3.2'

# https://apt.dockerproject.org/repo/dists/ubuntu-trusty/main/filelist
docker_versioned_pkg:
  latest: docker-engine
  1.9: docker-engine=1.9.0-0~{{ ansible_distribution_release|lower }}
  1.10: docker-engine=1.10.1-0~{{ ansible_distribution_release|lower }}

docker_package_info:
  pkg_mgr: apt
  pkgs:
    - "{{ docker_versioned_pkg[docker_version] }}"

docker_repo_key_info:
  pkg_key: apt_key
  keyserver: hkp://p80.pool.sks-keyservers.net:80
  repo_keys:
    - 58118E89F3A912897C070ADBF76221572C52609D

docker_repo_info:
  pkg_repo: apt_repository
  repos:
    - >
       deb https://apt.dockerproject.org/repo
       {{ ansible_distribution|lower }}-{{ ansible_distribution_release|lower }}
       main