Fixes #97, Triggers #98, Makes me sad: Fix Docker 18.09.0 startup issue on systemd systems.

tasks/docker-1809-shim.yml

@@ -0,0 +1,10 @@
+---
+- name: Ensure containerd service dir exists.
+  file:
+    path: /etc/systemd/system/containerd.service.d
+    state: directory
+
+- name: Add shim to ensure Docker can start in all environments.
+  template:
+    src: override.conf.j2
+    dest: /etc/systemd/system/containerd.service.d/override.conf

tasks/main.yml

@@ -11,6 +11,10 @@
     state: "{{ docker_package_state }}"
   notify: restart docker
 
+# TODO: Remove this shim once 18.09.1 or later is released.
+- import_tasks: docker-1809-shim.yml
+  when: ansible_service_mgr == 'systemd'
+
 - name: Ensure Docker is started and enabled at boot.
   service:
     name: docker

templates/override.conf.j2

@@ -0,0 +1,2 @@
+[Service]
+ExecStartPre=