Merge pull request #9491 from johngmyers/nodeport-dns

Default ClusterDNS appropriately when NodeLocalDNS is enabled
kubernetes · Jul 6, 2020 · a97fc42 · a97fc42
2 parents 61cb11b + 004f7b5
commit a97fc42
Show file tree

Hide file tree

Showing 3 changed files with 12 additions and 17 deletions.
diff --git a/docs/cluster_spec.md b/docs/cluster_spec.md
@@ -583,7 +583,7 @@ spec:
 
 ## Node local DNS cache
 
-As of kops 1.18, you can enable NodeLocal DNSCache if you are using CoreDNS. It is used to improve improve the Cluster DNS performance by running a dns caching agent on cluster nodes as a DaemonSet.
+As of kops 1.18, you can enable NodeLocal DNSCache if you are using CoreDNS. It is used to improve the Cluster DNS performance by running a dns caching agent on cluster nodes as a DaemonSet.
 
 ```yaml
 spec:
@@ -593,16 +593,6 @@ spec:
       enabled: true
 ```
 
-If you are using kube-proxy in ipvs mode or Cilium as CNI, you have to set the nodeLocalDNS as ClusterDNS.
-
-```yaml
-spec:
-  kubelet:
-    clusterDNS: 169.254.20.10
-  masterKubelet:
-    clusterDNS: 169.254.20.10
-```
-
 ## kubeControllerManager
 This block contains configurations for the `controller-manager`.
 

diff --git a/pkg/apis/kops/validation/validation.go b/pkg/apis/kops/validation/validation.go
@@ -1096,11 +1096,11 @@ func validateNodeLocalDNS(spec *kops.ClusterSpec, fldpath *field.Path) field.Err
 	}
 
 	if (spec.KubeProxy != nil && spec.KubeProxy.ProxyMode == "ipvs") || (spec.Networking != nil && spec.Networking.Cilium != nil) {
-		if spec.Kubelet != nil && spec.Kubelet.ClusterDNS != spec.KubeDNS.NodeLocalDNS.LocalIP {
+		if spec.Kubelet != nil && spec.Kubelet.ClusterDNS != "" && spec.Kubelet.ClusterDNS != spec.KubeDNS.NodeLocalDNS.LocalIP {
 			allErrs = append(allErrs, field.Forbidden(fldpath.Child("kubelet", "clusterDNS"), "Kubelet ClusterDNS must be set to the default IP address for LocalIP"))
 		}
 
-		if spec.MasterKubelet != nil && spec.MasterKubelet.ClusterDNS != spec.KubeDNS.NodeLocalDNS.LocalIP {
+		if spec.MasterKubelet != nil && spec.MasterKubelet.ClusterDNS != "" && spec.MasterKubelet.ClusterDNS != spec.KubeDNS.NodeLocalDNS.LocalIP {
 			allErrs = append(allErrs, field.Forbidden(fldpath.Child("kubelet", "clusterDNS"), "MasterKubelet ClusterDNS must be set to the default IP address for LocalIP"))
 		}
 	}

diff --git a/pkg/model/components/kubelet.go b/pkg/model/components/kubelet.go
@@ -82,11 +82,16 @@ func (b *KubeletOptionsBuilder) BuildOptions(o interface{}) error {
 	}
 
 	if clusterSpec.Kubelet.ClusterDNS == "" {
-		ip, err := WellKnownServiceIP(clusterSpec, 10)
-		if err != nil {
-			return err
+		if clusterSpec.KubeDNS != nil && clusterSpec.KubeDNS.NodeLocalDNS != nil && fi.BoolValue(clusterSpec.KubeDNS.NodeLocalDNS.Enabled) &&
+			((clusterSpec.KubeProxy != nil && clusterSpec.KubeProxy.ProxyMode == "ipvs") || (clusterSpec.Networking != nil && clusterSpec.Networking.Cilium != nil)) {
+			clusterSpec.Kubelet.ClusterDNS = clusterSpec.KubeDNS.NodeLocalDNS.LocalIP
+		} else {
+			ip, err := WellKnownServiceIP(clusterSpec, 10)
+			if err != nil {
+				return err
+			}
+			clusterSpec.Kubelet.ClusterDNS = ip.String()
 		}
-		clusterSpec.Kubelet.ClusterDNS = ip.String()
 	}
 
 	clusterSpec.MasterKubelet.RegisterSchedulable = fi.Bool(false)