tripleo-hieradata: add hieradata_files param

If hieradata_files is set (must be a list), Ansible will configure
/etc/puppet/hiera.yaml with the right configuration for Hiera.

Note: we now use hiera3 for backward compatibility but in the future we
will switch to hiera5.

Change-Id: Ia5f11ea1a2f16b736ed7053c5182c7f5a7eb1f4b
implements: blueprint reduce-deployment-resources

roles/tripleo-hieradata/README.md

@@ -12,6 +12,7 @@ Required:
 * `hieradata_variable_start_string` -- string marking the beginning of a template print statement.
 * `hieradata_variable_end_string` -- string marking the end of a template print statement.
 * `hieradata_per_host` -- whether or not we configure hieradata per host.
+* `hieradata_files` -- List of hieradata files (Order matters for Hierarchy).
 
 Test playbook
 -------------

roles/tripleo-hieradata/defaults/main.yaml

@@ -1,4 +1,5 @@
 hieradata_template: ""
+hieradata_files: []
 # jinja2 escape trick for simple {{ and }} strings:
 hieradata_variable_start_string: "{{ '{{' }}"
 hieradata_variable_end_string: "{{ '}}' }}"

roles/tripleo-hieradata/tasks/main.yaml

@@ -4,6 +4,22 @@
     state: directory
     mode: 0700
 
+- name: Write hiera config
+  when: hieradata_files != []
+  copy:
+    mode: 0600
+    dest:  /etc/puppet/hiera.yaml
+    # TODO(emilien) Switch to Hiera5 format once we stop calling Hiera CLI
+    # which is deprecated and should be replaced by "puppet lookup" command.
+    content: |
+      ---
+      :backends:
+        - json
+      :json:
+        :datadir: /etc/puppet/hieradata
+      :hierarchy:
+      {{ hieradata_files }}
+
 - name: Template hieradata file
   when: hieradata_template != ""
   delegate_to: localhost

roles/tripleo-hieradata/test-playbook.yaml

@@ -8,3 +8,6 @@
         # jinja2 escape trick for simple {{ and }} strings:
         variable_start_string: "{{ '{{' }}"
         variable_end_string: "{{ '}}' }}"
+        hieradata_files:
+          - node
+          - common