add ability to mount single config file

Change-Id: I328d73b6ee80410ad633fded1ef35d3ceeb77f2a
diff --git a/README.rst b/README.rst
index 0ee5fa5..e2be335 100644
--- a/README.rst
+++ b/README.rst
@@ -568,6 +568,19 @@
               key: policy.json
               path: policy.json
 
+To mount single configuration file instead of whole directory:
+
+.. code-block:: yaml
+
+  service:
+    memcached:
+      container:
+        memcached:
+          volumes:
+            - name: volume1
+              mountPath: /volume/config.conf
+              sub_path: config.conf
+
 Generating Jobs
 ===============
 
diff --git a/kubernetes/files/rc.yml b/kubernetes/files/rc.yml
index 04f737d..e012918 100644
--- a/kubernetes/files/rc.yml
+++ b/kubernetes/files/rc.yml
@@ -85,7 +85,10 @@
           {%- for volume in container.volumes %}
             - name:  {{ volume.name }}
               mountPath: {{ volume.mount }}
-              readOnly: {{ volume.read_only }}
+              readOnly: {{ volume.get('read_only', 'False') }}
+              {%- if volume.sub_path is defined %}
+              subPath: {{ volume.sub_path }}
+              {%- endif %}
           {%- endfor %}
           {%- endif %}
           {%- if container.liveness_probe is defined %}