Use zuul's install-docker role

This allows us to remove the sudo from the tox molecule environment, since
the install-docker role correctly adds the zuul user to the docker group.

Change-Id: Ib7abd22c0caf793a8a59d38a4f63df7e60a7b69e

playbooks/kayobe-tox-molecule/pre.yml

 ---
 - hosts: all
   roles:
-    - role: docker-engine
+    - role: install-docker

roles/docker-engine/tasks/main.yml

----
-# Docker community edition installation procedure for Ubuntu taken from
-# https://docs.docker.com/install/linux/docker-ce/ubuntu/#install-docker-ce-1.
-
-# TODO: Configure docker to use the registry mirror provided by OpenStack
-# infra. Kolla-ansible has code referencing
-# http://{{ zuul_site_mirror_fqdn }}:8081/registry-1.docker/, but this did not
-# seem to work.
-
-- name: Fail if OS family is not supported
-  fail:
-    msg: "OS family {{ ansible_os_family }} is not supported"
-  when: ansible_os_family not in ["Debian"]
-
-- name: Update apt package cache
-  apt:
-    update_cache: true
-  become: true
-
-- name: Ensure dependencies are installed
-  apt:
-    name: "{{ item }}"
-    state: installed
-  with_items:
-    - apt-transport-https
-    - ca-certificates
-    - curl
-    - software-properties-common
-  become: true
-
-- name: Ensure docker apt gpg key is installed
-  apt_key:
-    url: "https://download.docker.com/linux/ubuntu/gpg"
-    id: "0EBFCD88"
-    state: present
-  become: true
-
-- name: Ensure docker CE stable repository is present
-  apt_repository:
-    repo: "deb [arch=amd64] https://download.docker.com/linux/ubuntu {{ ansible_lsb.codename }} stable"
-    state: present
-  become: true
-
-- name: Update apt package cache
-  apt:
-    update_cache: true
-  become: true
-
-- name: Ensure docker-ce is installed
-  apt:
-    name: docker-ce
-    state: installed
-  become: true
-
-- name: Ensure docker group exists
-  group:
-    name: docker
-  become: true
-
-- name: Add user to docker group
-  user:
-    name: "{{ ansible_user_id }}"
-    append: yes
-    groups: docker
-  register: group_result
-  become: true
-
-# NOTE(mgoddard): We need to reset the SSH connection to pick up the new group
-# membership. For Ansible 2.3+, ideally we'd use a meta task with the
-# reset_connection option but due to
-# https://github.com/ansible/ansible/issues/27520 this does not work (checked
-# in Ansible 2.3.2.0). Various methods have been attempted, but none have been
-# found to work. Instead, we use sudo when executing tox.
-# Attempted solutions:
-# * reset_connection - see above.
-# * kill local ssh/remove control socket - Zuul blocks running local commands.
-# * kill remote sshd - causes the task to fail, error cannot be ignored.
-# * pause for SSH connection timeout - fails due to
-#   https://github.com/ansible/ansible/issues/31694.

tox.ini

@@ -60,17 +60,12 @@ commands =
 basepython = python2
 whitelist_externals =
     bash
-    sudo
 commands =
     # Install ansible role dependencies from Galaxy.
     ansible-galaxy install \
         -r {toxinidir}/requirements.yml \
         -p {toxinidir}/ansible/roles
-    # NOTE(mgoddard): We are executing the molecule command using sudo. This is
-    # to work around the inability to reset the SSH connection in order to pick
-    # up the Linux group membership change for the docker group. See the
-    # docker-engine role for further details.
-    sudo bash -c "source {envdir}/bin/activate && {toxinidir}/tools/test-molecule.sh {posargs}"
+    bash -c "source {envdir}/bin/activate && {toxinidir}/tools/test-molecule.sh {posargs}"
 
 [testenv:alint]
 basepython = python3