Always use coreDNS by default

upup/pkg/fi/cloudup/bootstrapchannelbuilder/bootstrapchannelbuilder.go

@@ -356,14 +356,8 @@ func (b *BootstrapChannelBuilder) buildAddons(c *fi.ModelBuilderContext) (*Addon
 
 	kubeDNS := b.Cluster.Spec.KubeDNS
 
-	// This checks if the Kubernetes version is greater than or equal to 1.20
-	// and makes the default DNS server as CoreDNS if the DNS provider is not specified
-	// and the Kubernetes version is >=1.19
 	if kubeDNS.Provider == "" {
-		kubeDNS.Provider = "KubeDNS"
-		if b.Cluster.IsKubernetesGTE("1.20") {
-			kubeDNS.Provider = "CoreDNS"
-		}
+		kubeDNS.Provider = "CoreDNS"
 	}
 
 	if kubeDNS.Provider == "KubeDNS" {

upup/pkg/fi/cloudup/tests/bootstrapchannelbuilder/metrics-server/insecure-1.19/manifest.yaml

@@ -19,11 +19,11 @@ spec:
       k8s-addon: core.addons.k8s.io
     version: 9.99.0
   - id: k8s-1.12
-    manifest: kube-dns.addons.k8s.io/k8s-1.12.yaml
-    manifestHash: 6031d02efd43be93b5e17323df6b5eb80d4e3149675fa0c58e86f610d60b94e2
-    name: kube-dns.addons.k8s.io
+    manifest: coredns.addons.k8s.io/k8s-1.12.yaml
+    manifestHash: c930f84e40f98a66d2d21f5abb02300980216e73abcc78d4641c4d65335fc065
+    name: coredns.addons.k8s.io
     selector:
-      k8s-addon: kube-dns.addons.k8s.io
+      k8s-addon: coredns.addons.k8s.io
     version: 9.99.0
   - id: k8s-1.9
     manifest: kubelet-api.rbac.addons.k8s.io/k8s-1.9.yaml

upup/pkg/fi/cloudup/tests/bootstrapchannelbuilder/metrics-server/secure-1.19/manifest.yaml

@@ -19,11 +19,11 @@ spec:
       k8s-addon: core.addons.k8s.io
     version: 9.99.0
   - id: k8s-1.12
-    manifest: kube-dns.addons.k8s.io/k8s-1.12.yaml
-    manifestHash: 6031d02efd43be93b5e17323df6b5eb80d4e3149675fa0c58e86f610d60b94e2
-    name: kube-dns.addons.k8s.io
+    manifest: coredns.addons.k8s.io/k8s-1.12.yaml
+    manifestHash: c930f84e40f98a66d2d21f5abb02300980216e73abcc78d4641c4d65335fc065
+    name: coredns.addons.k8s.io
     selector:
-      k8s-addon: kube-dns.addons.k8s.io
+      k8s-addon: coredns.addons.k8s.io
     version: 9.99.0
   - id: k8s-1.9
     manifest: kubelet-api.rbac.addons.k8s.io/k8s-1.9.yaml