Include default_docker_volume_type for magnum.conf

To create a magnum cluster, its required to specify
'default_docker_volume_type' with some default value (default cinder
 volume type). And, it also enables users to select
diffferent cinder volume types for their volumes.

Change-Id: I50b4c436875e4daac48a14fc1e119136eb5fd844

ansible/roles/magnum/defaults/main.yml

@@ -42,6 +42,9 @@ magnum_database_address: "{{ database_address }}:{{ database_port }}"
 # Magnum
 ####################
 enable_cluster_user_trust: False
+# The default cinder volume type to be used for container storage volume in clusters
+# that specify the docker-volume-size option. For example gp1, io1 etc
+default_docker_volume_type: ""
 
 
 ####################

ansible/roles/magnum/templates/magnum.conf.j2

@@ -18,6 +18,11 @@ workers = {{ openstack_service_workers }}
 connection = mysql+pymysql://{{ magnum_database_user }}:{{ magnum_database_password }}@{{ magnum_database_address }}/{{ magnum_database_name }}
 max_retries = -1
 
+{% if enable_cinder | bool %}
+[cinder]
+default_docker_volume_type = {{ default_docker_volume_type }}
+{% endif %}
+
 [heat_client]
 region_name = {{ openstack_region_name }}
 endpoint_type = internalURL

releasenotes/notes/default_docker_volume_type-251636f92cb73aee.yaml

+---
+upgrade:
+  - |
+    Added default_docker_volume_type for magnum which is required to
+    specify the default cinder volume type to be used for container
+    storage volume in clusters that specify the docker-volume-size
+    option. For example gp1, io1 etc.