Merge "Support arbitrarily named Docker drivers"

ansible/roles/docker/defaults/main.yml

 ---
-# Name of the docker storage driver. Supported values include 'devicemapper'
-# and 'overlay'.
+# Name of the docker storage driver.
 docker_storage_driver: devicemapper
 
 # Name of the docker storage LVM volume group.

ansible/roles/docker/tasks/main.yml

 ---
-- name: Fail when the storage driver is invalid
-  fail:
-    msg: >
-      Storage driver {{ docker_storage_driver }} is invalid. Valid drivers
-      include 'devicemapper' and 'overlay'.
-  when: docker_storage_driver not in ['devicemapper', 'overlay']
-
 - name: Set a fact about the virtualenv on the remote system
   set_fact:
     virtualenv: "{{ ansible_python_interpreter | dirname | dirname }}"

ansible/roles/docker/templates/daemon.json.j2

@@ -6,7 +6,7 @@
 {%- endfor %}
   ],
 {%- endif %}
-  "storage-driver": "{% if docker_storage_driver == 'devicemapper' %}devicemapper{% else %}overlay{% endif %}",
+  "storage-driver": "{{ docker_storage_driver }}",
 {% if docker_daemon_mtu %}
   "mtu": {{ docker_daemon_mtu }},
 {% endif %}

etc/kayobe/docker.yml

@@ -2,8 +2,7 @@
 ###############################################################################
 # Docker configuration.
 
-# Name of the docker storage driver. Supported values include 'devicemapper'
-# and 'overlay'.
+# Name of the docker storage driver. Default is 'devicemapper'.
 #docker_storage_driver:
 
 # Name of the docker storage LVM volume group.

releasenotes/notes/docker-storage-driver-7d560e7d350b14ba.yaml

+---
+features:
+  - |
+    Adds support for arbitrary Docker storage drivers, configured via
+    ``docker_storage_driver``. Previously only ``devicemapper`` and ``overlay``
+    were supported.