From d570ea6381344950498a91c7ef7e59b7df92b9b7 Mon Sep 17 00:00:00 2001
From: Manuel de Brito Fontes <aledbf@gmail.com>
Date: Tue, 10 Jan 2017 09:54:32 -0300
Subject: [PATCH] Add resolver configuration to nginx

---
 controllers/nginx/pkg/template/configmap.go      | 8 ++++++++
 controllers/nginx/pkg/template/configmap_test.go | 7 +++++++
 2 files changed, 15 insertions(+)

diff --git a/controllers/nginx/pkg/template/configmap.go b/controllers/nginx/pkg/template/configmap.go
index 76d0b90f1..9e1b8ab9c 100644
--- a/controllers/nginx/pkg/template/configmap.go
+++ b/controllers/nginx/pkg/template/configmap.go
@@ -26,6 +26,7 @@ import (
 	"k8s.io/kubernetes/pkg/api"
 
 	"k8s.io/ingress/controllers/nginx/pkg/config"
+	"k8s.io/ingress/core/pkg/net/dns"
 )
 
 const (
@@ -69,6 +70,13 @@ func ReadConfig(conf *api.ConfigMap) config.Configuration {
 	to.SkipAccessLogURLs = skipUrls
 	to.WhitelistSourceRange = whitelist
 
+	h, err := dns.GetSystemNameServers()
+	if err != nil {
+		glog.Warningf("unexpected error reading system nameservers: %v", err)
+	} else {
+		to.Resolver = h
+	}
+
 	config := &mapstructure.DecoderConfig{
 		Metadata:         nil,
 		WeaklyTypedInput: true,
diff --git a/controllers/nginx/pkg/template/configmap_test.go b/controllers/nginx/pkg/template/configmap_test.go
index 0edbefe24..0bbdc4cf4 100644
--- a/controllers/nginx/pkg/template/configmap_test.go
+++ b/controllers/nginx/pkg/template/configmap_test.go
@@ -21,6 +21,7 @@ import (
 	"testing"
 
 	"k8s.io/ingress/controllers/nginx/pkg/config"
+	"k8s.io/ingress/core/pkg/net/dns"
 	"k8s.io/kubernetes/pkg/api"
 )
 
@@ -53,6 +54,12 @@ func TestMergeConfigMapToStruct(t *testing.T) {
 	def.UseProxyProtocol = true
 	def.GzipTypes = "text/html"
 
+	h, err := dns.GetSystemNameServers()
+	if err != nil {
+		t.Errorf("unexpected error: %v", err)
+	}
+	def.Resolver = h
+
 	to := ReadConfig(conf)
 	if !reflect.DeepEqual(def, to) {
 		t.Errorf("expected %v but retuned %v", def, to)