From a32671a9cddddf6c7c9c2c4d215a3b577fce3854 Mon Sep 17 00:00:00 2001
From: Dominic Gunn <dominic@fable.sh>
Date: Mon, 17 Jun 2019 14:08:46 +0100
Subject: [PATCH] Configurable coredns ttl

---
 builtin/files/cluster.yaml.tmpl               |  3 +++
 .../files/userdata/cloud-config-controller    |  3 ++-
 pkg/api/cluster.go                            |  1 +
 pkg/api/types.go                              |  1 +
 pkg/model/cluster_test.go                     | 22 +++++++++++++++++++
 5 files changed, 29 insertions(+), 1 deletion(-)

diff --git a/builtin/files/cluster.yaml.tmpl b/builtin/files/cluster.yaml.tmpl
index b7eff80b7..d2ea6acd0 100644
--- a/builtin/files/cluster.yaml.tmpl
+++ b/builtin/files/cluster.yaml.tmpl
@@ -1328,6 +1328,9 @@ kubeDns:
   # - --neg-ttl=10
   # - --no-ping
 
+  # When enabled, will modify the TTL of the coredns service.
+  # ttl: 30
+
   # When enabled, will deploy kube-dns to K8s controllers instead of workers.
   # deployToControllers: false
 
diff --git a/builtin/files/userdata/cloud-config-controller b/builtin/files/userdata/cloud-config-controller
index 4cb773e9a..c2878f728 100644
--- a/builtin/files/userdata/cloud-config-controller
+++ b/builtin/files/userdata/cloud-config-controller
@@ -3784,13 +3784,14 @@ write_files:
                     pods insecure
                     upstream
                     fallthrough in-addr.arpa ip6.arpa
+                    ttl {{ .KubeDns.TTL }}
                 }
                 forward . /etc/resolv.conf {
                     except cluster.local
                     health_check 5s
                 }
                 prometheus :9153
-                cache 30
+                cache {{ .KubeDns.TTL }}
                 loop
                 reload
                 loadbalance
diff --git a/pkg/api/cluster.go b/pkg/api/cluster.go
index 1d61f86ab..639b2e5d8 100644
--- a/pkg/api/cluster.go
+++ b/pkg/api/cluster.go
@@ -154,6 +154,7 @@ func NewDefaultCluster() *Cluster {
 				Provider:            "coredns",
 				NodeLocalResolver:   false,
 				DeployToControllers: false,
+				TTL:                 30,
 				Autoscaler: KubeDnsAutoscaler{
 					CoresPerReplica: 256,
 					NodesPerReplica: 16,
diff --git a/pkg/api/types.go b/pkg/api/types.go
index 4c648dc6d..91f7a253d 100644
--- a/pkg/api/types.go
+++ b/pkg/api/types.go
@@ -209,6 +209,7 @@ type KubeDns struct {
 	NodeLocalResolver        bool              `yaml:"nodeLocalResolver"`
 	NodeLocalResolverOptions []string          `yaml:"nodeLocalResolverOptions"`
 	DeployToControllers      bool              `yaml:"deployToControllers"`
+	TTL                      int               `yaml:"ttl"`
 	Autoscaler               KubeDnsAutoscaler `yaml:"autoscaler"`
 }
 
diff --git a/pkg/model/cluster_test.go b/pkg/model/cluster_test.go
index 1ff319c6e..f71f625f7 100644
--- a/pkg/model/cluster_test.go
+++ b/pkg/model/cluster_test.go
@@ -1122,6 +1122,7 @@ func TestKubeDns(t *testing.T) {
 				Provider:            "coredns",
 				NodeLocalResolver:   false,
 				DeployToControllers: false,
+				TTL:                 30,
 				Autoscaler: api.KubeDnsAutoscaler{
 					CoresPerReplica: 256,
 					NodesPerReplica: 16,
@@ -1139,6 +1140,7 @@ kubeDns:
 				Provider:            "coredns",
 				NodeLocalResolver:   false,
 				DeployToControllers: false,
+				TTL:                 30,
 				Autoscaler: api.KubeDnsAutoscaler{
 					CoresPerReplica: 256,
 					NodesPerReplica: 16,
@@ -1160,6 +1162,7 @@ kubeDns:
 				Provider:            "coredns",
 				NodeLocalResolver:   true,
 				DeployToControllers: true,
+				TTL:                 30,
 				Autoscaler: api.KubeDnsAutoscaler{
 					CoresPerReplica: 5,
 					NodesPerReplica: 10,
@@ -1176,6 +1179,25 @@ kubeDns:
 				Provider:            "coredns",
 				NodeLocalResolver:   false,
 				DeployToControllers: false,
+				TTL:                 30,
+				Autoscaler: api.KubeDnsAutoscaler{
+					CoresPerReplica: 256,
+					NodesPerReplica: 16,
+					Min:             2,
+				},
+			},
+		},
+		{
+			conf: `
+kubeDns:
+  provider: coredns
+  ttl: 5
+`,
+			kubeDns: api.KubeDns{
+				Provider:            "coredns",
+				NodeLocalResolver:   false,
+				DeployToControllers: false,
+				TTL:                 5,
 				Autoscaler: api.KubeDnsAutoscaler{
 					CoresPerReplica: 256,
 					NodesPerReplica: 16,