Support configuration of yum.conf

Options are configured via the 'yum_config' variable.

Change-Id: Iaf46dbf22e0ad2b9e43926e899ce454d19662cc3
Story: 2004935
Task: 29327

ansible/roles/yum/defaults/main.yml

@@ -1,4 +1,8 @@
 ---
+# Yum configuration. Dict mapping Yum config option names to their values.
+# yum_config:
+#   proxy: http://proxy.example.com
+yum_config: {}
 
 # Whether or not to use a local Yum mirror.
 yum_use_local_mirror: false

ansible/roles/yum/tasks/local-mirror.yml

@@ -1,5 +1,4 @@
 ---
-
 - name: Replace | Disable YUM fastestmirror plugin (CentOS)
   replace:
     dest: /etc/yum/pluginconf.d/fastestmirror.conf

ansible/roles/yum/tasks/main.yml

@@ -1,6 +1,15 @@
 ---
 - block:
-    - include_tasks: redhat.yml
+    - name: Ensure yum.conf configuration exists
+      ini_file:
+        path: /etc/yum.conf
+        section: "main"
+        option: "{{ item.key }}"
+        value:  "{{ item.value }}"
+      loop: "{{ query('dict', yum_config) }}"
+      become: true
+
+    - include_tasks: local-mirror.yml
       when: yum_use_local_mirror | bool
 
     - include_tasks: custom_repo.yml

doc/source/configuration/hosts.rst

@@ -176,6 +176,19 @@ Package Repositories
 Kayobe supports configuration of package repositories via Yum, via variables in
 ``${KAYOBE_CONFIG_PATH}/yum.yml``.
 
+Configuration of yum.conf
+-------------------------
+
+Global configuration of Yum is stored in ``/etc/yum.conf``, and options can be
+set via the ``yum_config`` variable. Options are added to the ``[main]``
+section of the file. For example, to configure Yum to use a proxy server:
+
+.. code-block:: yaml
+   :caption: ``yum.yml``
+
+   yum_config:
+     proxy: https://proxy.example.com
+
 CentOS and EPEL Mirrors
 -----------------------
 

etc/kayobe/yum.yml

@@ -1,4 +1,8 @@
 ---
+# Yum configuration. Dict mapping Yum config option names to their values.
+# yum_config:
+#   proxy: http://proxy.example.com
+#yum_config:
 
 # Whether or not to use a local Yum mirror.
 #yum_use_local_mirror: false

releasenotes/notes/yum-config-58274185a00004e8.yaml

@@ -0,0 +1,5 @@
+---
+features:
+  - |
+    Adds support for configuration of options in ``/etc/yum.conf``, via the
+    ``yum_config`` variable.