Playbook to upgrade containers

Moved Ansible host requirements to 'ansible' role and created role
'upgrade' and playbook to help with upgrading containers.

roles/ansible/tasks/main.yml

@@ -0,0 +1,16 @@
+- name: 'Install Ansible dependency: python-apt'
+  shell: 'apt-get update && apt-get install python-apt -y'
+  args:
+    creates: /usr/lib/python2.7/dist-packages/apt
+    warn: false
+
+- name: 'Install Ansible dependency: aptitude'
+  apt:
+    name: 'aptitude'
+    state: present
+    force_apt_get: true
+
+- name: 'Install Ansible dependency: python-docker'
+  apt:
+    name: python-docker
+    state: present

roles/upgrade/tasks/main.yml

@@ -0,0 +1,38 @@
+- name: Download new Traefik container
+  docker_image:
+    name: "traefik:{{ traefik_version }}"
+    source: pull
+  register: new_traefik
+
+- name: Download new WordPress container
+  docker_image:
+    name: "wordpress:{{ wordpress_version }}"
+    source: pull
+  register: new_wordpress
+
+- name: Download new MariaDB container
+  docker_image:
+    name: "mariadb:{{ mariadb_version }}"
+    source: pull
+  register: new_mariadb
+
+- name: Stop and remove old Traefik container
+  docker_container:
+    name: "{{ traefik_name }}"
+    image: "traefik:{{ traefik_version }}"
+    state: absent
+  when: new_traefik.changed
+
+- name: Stop and remove old WordPress container
+  docker_container:
+    name: "{{ wordpress_name }}"
+    image: "wordpress:{{ wordpress_version }}"
+    state: absent
+  when: new_wordpress.changed
+
+- name: Stop and remove old MariaDB container
+  docker_container:
+    name: "{{ mariadb_name }}"
+    image: "mariadb:{{ mariadb_version }}"
+    state: absent
+  when: new_mariadb.changed