Move Cinder-volumes to "on metal"

Cinder-volumes is tightly coupled to the storage host and doesn't
gain from the benefits of containerization. This patch moves the default
location for cinder-scheduler into it's own container on the
"storage-infra_hosts", and the default location for cinder-volumes to be
"on metal" in the openstack_environment cinder.yml file.

Added documentation to suggest that you may want to remove "is_metal:
true" from cinder-volumes service when not using lvm.

Change-Id: I1879b1aa6dbe69a5a7e769a43b849441a38feeb8
Closes-Bug: #1433240

etc/openstack_deploy/env.d/cinder.yml

@@ -35,13 +35,27 @@ container_skel:
     properties:
       service_name: cinder
       container_release: trusty
+  cinder_scheduler_container:
+    belongs_to:
+      - infra_containers
+      - storage-infra_containers
+    contains:
+      - cinder_scheduler
+    properties:
+      service_name: cinder
+      container_release: trusty
   cinder_volumes_container:
     belongs_to:
       - storage_containers
     contains:
-      - cinder_scheduler
       - cinder_volume
     properties:
+# When using lvm as a cinder backend its advised to run cinder-volumes on metal.
+# If you are using a different backend you may want to remove "is_metal: true".
+# Otherwise if cinder-volumes is already running in containers you may want to
+# leave is_metal off, alternatively you will have to migrate your volumes once
+# deployed on metal.
+      is_metal: true
       service_name: cinder
       container_release: trusty
 

etc/openstack_deploy/openstack_user_config.yml.example

@@ -509,6 +509,8 @@
 #           Option: volume_driver (required, string)
 #           Name of volume driver,
 #           'cinder.volume.drivers.nfs.NfsDriver'.
+#           NB. When using NFS driver you may want to adjust your
+#           env.d/cinder.yml file to run cinder-volumes in containers.
 #
 #           Option: nfs_shares_config (optional, string)
 #           File containing list of NFS shares available to cinder, typically
@@ -523,6 +525,8 @@
 #           Option: volume_driver (required, string)
 #           Name of volume driver,
 #           'cinder.volume.drivers.netapp.common.NetAppDriver'.
+#           NB. When using NetApp drivers you may want to adjust your
+#           env.d/cinder.yml file to run cinder-volumes in containers.
 #
 #           Option: netapp_storage_family (required, string)
 #           Access method, typically 'ontap_7mode' or 'ontap_cluster'.