Deprecate the redundant cinder::backend_host parameter

The cinder::backend_host parameter is redundant, because it is not used
in the cinder class where the parameter is defined but is used to only
override the cinder::backends::backend_host parameter.

Change-Id: Ife5f8bdcfd4e982b7ffa5532b2a23d48c65d501f

manifests/backends.pp

@@ -12,12 +12,12 @@
 #
 # [*backend_host*]
 #   (optional) Backend override of host value.
-#   Defaults to undef
+#   Defaults to $::os_service_default
 #
 # Author: Andrew Woodward <awoodward@mirantis.com>
 class cinder::backends (
   $enabled_backends = undef,
-  $backend_host     = undef,
+  $backend_host     = $::os_service_default,
 ) {
 
   include cinder::deps
@@ -26,6 +26,10 @@ class cinder::backends (
     $backend_host_real = $::cinder::backend_host
   } else {
     $backend_host_real = $backend_host
+    if ! $backend_host_real {
+      warning('Using a false value for backend_host is deprecated. \
+Use $::os_service_default instead')
+    }
   }
 
   if $enabled_backends == undef {

manifests/init.pp

@@ -337,7 +337,6 @@ class cinder (
   $host                               = $::os_service_default,
   $enable_new_services                = $::os_service_default,
   $purge_config                       = false,
-  $backend_host                       = undef,
   $enable_force_upload                = $::os_service_default,
   # DEPRECATED PARAMETERS
   $database_min_pool_size             = undef,
@@ -348,6 +347,7 @@ class cinder (
   $database_retry_interval            = undef,
   $database_max_overflow              = undef,
   $amqp_allow_insecure_clients        = undef,
+  $backend_host                       = undef,
 ) inherits cinder::params {
 
   include cinder::deps
@@ -465,15 +465,14 @@ removed in a future realse. Use cinder::db::database_max_overflow instead')
     'key_manager/backend':                      value => $keymgr_backend;
     'barbican/barbican_endpoint':               value => $keymgr_encryption_api_url;
     'barbican/auth_endpoint':                   value => $keymgr_encryption_auth_url;
-    # NOTE(abishop): $backend_host is not written here because it is not a valid
-    # DEFAULT option. It is only recognized in the backend sections. Instead,
-    # for backward compatibility, backends.pp references this parameter.
   }
 
   if $backend_host != undef {
     if defined(Class[cinder::backends]){
       fail('The cinder::backend_host parameter has no effect unless cinder::backends is included later')
     }
+    warning('The cinder::backend_host parameter is deprecated. \
+Use the cinder::backends::backend_host parameter instead')
   }
 
   # V3 APIs

releasenotes/notes/deprecate-cinder-backend_host-8998890a80cbf783.yaml

@@ -0,0 +1,10 @@
+---
+deprecations:
+  - |
+    The ``cinder::backend_host`` parameter has been deprecated and will be
+    remove in a future release. Use the ``cinder::backends::backend_host``
+    parameter instead.
+
+  - |
+    Passing a false value for ``cinder::backends::backend_host`` has been
+    deprecated. Use ``$::os_service_default`` instead.

spec/classes/cinder_backends_spec.rb

@@ -43,9 +43,9 @@ describe 'cinder::backends' do
 
       it 'configures cinder.conf with default params' do
         is_expected.to contain_cinder_config('DEFAULT/enabled_backends').with_value(p[:enabled_backends].join(','))
-        is_expected.to_not contain_cinder_config('lowcost/backend_host')
+        is_expected.to contain_cinder_config('lowcost/backend_host').with_value('<SERVICE DEFAULT>')
-        is_expected.to_not contain_cinder_config('regular/backend_host')
+        is_expected.to contain_cinder_config('regular/backend_host').with_value('<SERVICE DEFAULT>')
-        is_expected.to_not contain_cinder_config('premium/backend_host')
+        is_expected.to contain_cinder_config('premium/backend_host').with_value('<SERVICE DEFAULT>')
       end
     end