Support to configure cinder backend_defaults

This patch introduces a new Class cinder::backend::defaults, that
provides a way to configure parameters for all cinder
backends by default in [backend_defaults] section of
cinder configuration file.

This parameter use_multipath_for_image_xfer is supported currently.

Change-Id: Ie7cb0c11a2b9526b61a70a5f359862a24723026c

manifests/backend/defaults.pp

@@ -0,0 +1,21 @@
+# == Class: cinder::backend::defaults
+#
+# Cinder backend defaults
+#
+# === Parameters
+#
+# [*use_multipath_for_image_xfer*]
+#   (Optional) Whether to use multipath during create-volume-from-image and
+#   copy-volume-to-image operations.
+#   Defaults to $::os_service_default
+#
+class cinder::backend::defaults (
+  $use_multipath_for_image_xfer = $::os_service_default,
+) {
+
+  include cinder::deps
+
+  cinder_config {
+    'backend_defaults/use_multipath_for_image_xfer': value => $use_multipath_for_image_xfer;
+  }
+}

releasenotes/notes/introduce_new_class_for_cinder_backend_defaults-f1f63f755dfdef47.yaml

@@ -0,0 +1,7 @@
+---
+features:
+    - |
+      Introduce a new Class cinder::backend::defaults, that provides a
+      way to configure parameters for all cinder backends in [backend_defaults]
+      section of cinder configuration file.
+      This parameter ``use_multipath_for_image_xfer`` is supported currently.

spec/classes/cinder_backend_defaults_spec.rb

@@ -0,0 +1,30 @@
+require 'spec_helper'
+
+describe 'cinder::backend::defaults' do
+
+  shared_examples 'cinder backend defaults' do
+
+    context 'configure cinder with default backend_defaults parameters' do
+      it { is_expected.to contain_cinder_config('backend_defaults/use_multipath_for_image_xfer').with_value('<SERVICE DEFAULT>') }
+    end
+
+    context 'configure cinder with user defined backend_defaults parameters' do
+      let(:params) do
+        { :use_multipath_for_image_xfer => true, }
+      end
+      it { is_expected.to contain_cinder_config('backend_defaults/use_multipath_for_image_xfer').with_value(true) }
+    end
+  end
+
+  on_supported_os({
+    :supported_os => OSDefaults.get_supported_os
+  }).each do |os,facts|
+    context "on #{os}" do
+      let (:facts) do
+        facts.merge!(OSDefaults.get_facts)
+      end
+
+      it_behaves_like 'cinder backend defaults'
+    end
+  end
+end

spec/classes/cinder_backends_spec.rb

@@ -71,7 +71,7 @@ describe 'cinder::backends' do
   end
 
   on_supported_os({
-    :supported_os   => OSDefaults.get_supported_os
+    :supported_os => OSDefaults.get_supported_os
   }).each do |os,facts|
     context "on #{os}" do
       let (:facts) do