Add hook to generate metadata from service profiles

This enables the deployer to dynamically add nova metadata to the
servers based on the output of service profiles that implement the
metadata_settings key in the role_data output for the profiles.

One can set an implementation via the OS::TripleO::ServerMetadataHook
resource, which currently is set as OS::Heat::None. So, because of
the default implementation, if left untouched it actually does
nothing.

Currently, besides the list, which is metadata_settings, this hook also
takes the name of the node that it's setting the metadata for.

This is useful for nova vendordata plugins that can parse said metadata.

Change-Id: I8a937f711f0b90156fbb6c4632760435ef846474

2 files changed, 20 insertions, 0 deletions

diff --git a/puppet/services/README.rst b/puppet/services/README.rst
index 856b306e..6e4e9c1d 100644
--- a/puppet/services/README.rst
+++ b/puppet/services/README.rst
@@ -74,3 +74,17 @@ step, "step2" for the second, etc.
    6) Start control-plane services
 
    7) Any additional online migration tasks (e.g data migrations)
+
+Nova Server Metadata Settings
+-----------------------------
+
+One can use the hook of type `OS::TripleO::ServiceServerMetadataHook` to pass
+entries to the nova instances' metadata. It is, however, disabled by default.
+In order to overwrite it one needs to define it in the resource registry. An
+implementation of this hook needs to conform to the following:
+
+* It needs to define an input called `RoleData` of json type. This gets as
+  input the contents of the `role_data` for each role's ServiceChain.
+
+* This needs to define an output called `metadata` which will be given to the
+  Nova Server resource as the instance's metadata.
diff --git a/puppet/services/services.yaml b/puppet/services/services.yaml
index 13df5bbe..97f87061 100644
--- a/puppet/services/services.yaml
+++ b/puppet/services/services.yaml
@@ -42,6 +42,11 @@ resources:
   LoggingConfiguration:
     type: OS::TripleO::LoggingConfiguration
 
+  ServiceServerMetadataHook:
+    type: OS::TripleO::ServiceServerMetadataHook
+    properties:
+      RoleData: {get_attr: [ServiceChain, role_data]}
+
 outputs:
   role_data:
     description: Combined Role data for this set of services.
@@ -113,3 +118,4 @@ outputs:
           # Note we use distinct() here to filter any identical tasks, e.g yum update for all services
           expression: $.data.where($ != null).select($.get('upgrade_tasks')).where($ != null).flatten().distinct()
           data: {get_attr: [ServiceChain, role_data]}
+      service_metadata_settings: {get_attr: [ServiceServerMetadataHook, metadata]}