Add support for free-form configuration of kolla-build.conf

Provide extra configuration of kolla-build.conf via
$KAYOBE_CONFIG_PATH/kolla/kolla-build.conf.

ansible/kolla-build.yml

@@ -4,3 +4,4 @@
   roles:
     - role: kolla
     - role: kolla-build
+      kolla_build_extra_config_path: "{{ kayobe_config_path }}/kolla/kolla-build.conf"

ansible/roles/kolla-build/defaults/main.yml

@@ -2,6 +2,9 @@
 # Directory where Kolla config files will be installed.
 kolla_build_config_path:
 
+# Path to extra kolla configuration files.
+kolla_build_extra_config_path:
+
 # Valid options are [ centos, fedora, oraclelinux, ubuntu ]
 kolla_base_distro:
 
@@ -34,3 +37,6 @@ kolla_build_blocks: {}
 # most commonly packages. The operation should be one of override, append or
 # remove. The value should be a list.
 kolla_build_customizations: {}
+
+# Free-form extra configuration for kolla-build.
+kolla_extra_build: {}

ansible/roles/kolla-build/tasks/main.yml

@@ -1,4 +1,18 @@
 ---
+- name: Check whether a Kolla build extra configuration file exists
+  local_action:
+    module: stat
+    path: "{{ kolla_build_extra_config_path }}"
+    get_checksum: False
+    get_md5: False
+    mime: False
+  register: stat_result
+
+- name: Set a fact containing extra configuration
+  set_fact:
+    kolla_build_extra_config: "{{ lookup('template', kolla_build_extra_config_path) }}"
+  when: stat_result.stat.exists
+
 - name: Ensure the Kolla build configuration files exist
   template:
     src: "{{ item.src }}"

ansible/roles/kolla-build/templates/kolla-build.conf.j2

@@ -33,3 +33,11 @@ reference = {{ source_def.reference }}
 {% endif %}
 
 {% endfor %}
+
+{% if kolla_build_extra_config is defined %}
+#######################
+# Extra configuration
+#######################
+
+{{ kolla_build_extra_config }}
+{% endif %}