Set default TTL for memcache item expiration

Fixes: PROD-26960

Change-Id: I8880277c1c0fa3b6cbea1c26fcdf09d13b92a5e8
(cherry picked from commit 25b53070d6d625c58fb4a92728130b6122caae98)

Enable default TTL for memcache item expiration

Includes oslo_templates/files/queens/oslo/_cache.conf file
in the [cache] section of nova.conf

Change-Id: I7e6ed812cc95cb492b255171c12314d89a8343de
Related-Prod: PROD-26960
(cherry picked from commit 068f1534282f5f1d0a8be86c9425e6e5a20d48f4)
diff --git a/metadata/service/control/single.yml b/metadata/service/control/single.yml
index c525974..5030462 100644
--- a/metadata/service/control/single.yml
+++ b/metadata/service/control/single.yml
@@ -74,6 +74,13 @@
         password: ${_param:metadata_password}
       cache:
         engine: memcached
+        # NOTE (dukov) Do not change this unless you 100% sure what you are doing
+        expiration_time: 600
+        backend_argument:
+          # NOTE (dukov) WARNING! This parameter depends on expiration_time.
+          # Value of 'memcached_expire_time' must be bigger than 'expiration_time'
+          memcached_expire_time:
+            value: 660
         members:
         - host: ${_param:single_address}
           port: 11211