--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/contrib/provision/roles/nginx/defaults/main.yml	Thu Apr 07 23:10:03 2016 +0800
@@ -0,0 +1,4 @@
+---
+nginx_resolver: '8.8.8.8 [2001:4860:4860::8888] 8.8.4.4 [2001:4860:4860::8844]'
+nginx_resolver_timeout: 5s
+...

--- a/contrib/provision/roles/tram-im/templates/etc/nginx/sites-available/tram-im	Thu Apr 07 23:00:45 2016 +0800
+++ b/contrib/provision/roles/tram-im/templates/etc/nginx/sites-available/tram-im	Thu Apr 07 23:10:03 2016 +0800
@@ -29,8 +29,8 @@
 
     # OCSP
     ssl_stapling on;
-    resolver 8.8.8.8 [2001:4860:4860::8888] 8.8.4.4 [2001:4860:4860::8844];
-    resolver_timeout 5s;
+    resolver {{ nginx_resolver }};
+    resolver_timeout {{ nginx_resolver_timeout }};
 
     # access from <frame | iframe | object>: DENY | SAMEORIGIN | ALLOW-FROM uri
     add_header X-Frame-Options 'SAMEORIGIN';