make 6443 as a constant

kind/actions/cluster_actions.go

@@ -24,6 +24,7 @@ import (
 
 	"github.com/pkg/errors"
 	k8sversion "k8s.io/apimachinery/pkg/util/version"
+	constkind "sigs.k8s.io/cluster-api-provider-docker/kind/constants"
 	"sigs.k8s.io/cluster-api-provider-docker/kind/kubeadm"
 	"sigs.k8s.io/cluster-api-provider-docker/third_party/forked/loadbalancer"
 	"sigs.k8s.io/kind/pkg/cluster/constants"
@@ -99,7 +100,7 @@ func ConfigureLoadBalancer(clusterName string) error {
 		if err != nil {
 			return errors.Wrapf(err, "failed to get IP for node %s", n.Name())
 		}
-		backendServers[n.Name()] = fmt.Sprintf("%s:%d", controlPlaneIPv4, 6443)
+		backendServers[n.Name()] = fmt.Sprintf("%s:%d", controlPlaneIPv4, constkind.APIServerPort)
 	}
 
 	// create loadbalancer config data
@@ -126,7 +127,8 @@ func KubeadmConfig(node *nodes.Node, clusterName, lbip string) error {
 		return errors.Wrap(err, "failed to get kubernetes version from node")
 	}
 
-	kubeadmConfig, err := kubeadm.InitConfiguration(kubeVersion, clusterName, fmt.Sprintf("%s:%d", lbip, 6443))
+	kubeadmConfig, err := kubeadm.InitConfiguration(kubeVersion, clusterName,
+		fmt.Sprintf("%s:%d", lbip, constkind.APIServerPort))
 
 	if err != nil {
 		return errors.Wrap(err, "failed to generate kubeadm config content")

kind/actions/kind.go

@@ -27,6 +27,7 @@ import (
 	"strings"
 
 	"github.com/pkg/errors"
+	constkind "sigs.k8s.io/cluster-api-provider-docker/kind/constants"
 	"sigs.k8s.io/cluster-api-provider-docker/third_party/forked/loadbalancer"
 	"sigs.k8s.io/kind/pkg/cluster/config/defaults"
 	"sigs.k8s.io/kind/pkg/cluster/constants"
@@ -247,7 +248,7 @@ func GetLoadBalancerHostAndPort(allNodes []nodes.Node) (string, int32, error) {
 	if err != nil {
 		return "", 0, err
 	}
-	port, err := node.Ports(6443)
+	port, err := node.Ports(constkind.APIServerPort)
 	return ipv4, port, err
 }
 

kind/constants/constants.go

@@ -0,0 +1,21 @@
+/*
+Copyright 2019 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package constants
+
+// APIServerPort is the expected default APIServerPort on the control plane node(s)
+// https://kubernetes.io/docs/reference/access-authn-authz/controlling-access/#api-server-ports-and-ips
+const APIServerPort = 6443

kind/kubeadm/config.go

@@ -24,6 +24,7 @@ import (
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	kubeadmv1beta1 "k8s.io/kubernetes/cmd/kubeadm/app/apis/kubeadm/v1beta1"
 	"k8s.io/kubernetes/pkg/kubelet/apis/config"
+	"sigs.k8s.io/cluster-api-provider-docker/kind/constants"
 )
 
 const (
@@ -52,7 +53,7 @@ func InitConfiguration(version, name, controlPlaneEndpoint string) ([]byte, erro
 			},
 		},
 		LocalAPIEndpoint: kubeadmv1beta1.APIEndpoint{
-			BindPort: int32(6443),
+			BindPort: int32(constants.APIServerPort),
 		},
 		NodeRegistration: kubeadmv1beta1.NodeRegistrationOptions{
 			CRISocket: "/run/containerd/containerd.sock",