fix get external address for the authentication service

internal/discovery/foreign-cluster-operator/foreign-cluster-controller.go

@@ -494,8 +494,18 @@ func (r *ForeignClusterReconciler) getAddress() (string, error) {
 			klog.Error(err)
 			return "", err
 		}
+		lbIngress := svc.Status.LoadBalancer.Ingress[0]
 		// return the external service IP
-		return svc.Status.LoadBalancer.Ingress[0].IP, nil
+		if hostname := lbIngress.Hostname; hostname != "" {
+			return hostname, nil
+		} else if ip := lbIngress.IP; ip != "" {
+			return ip, nil
+		} else {
+			// the service has no external IPs
+			err := goerrors.New("no valid external IP for LoadBalancer Service")
+			klog.Error(err)
+			return "", err
+		}
 	}
 
 	// get the IP from the Nodes, to be used with NodePort services
@@ -515,23 +525,12 @@ func (r *ForeignClusterReconciler) getAddress() (string, error) {
 	}
 
 	node := nodes.Items[0]
-	for _, addr := range node.Status.Addresses {
-		// get the accresses that are IPs, other addresses (like the hostname) can not be reachable and valid for a remote host
-		if addr.Type == apiv1.NodeExternalIP || addr.Type == apiv1.NodeInternalIP {
-			return addr.Address, nil
-		}
-	}
+	return discoveryPkg.GetAddress(&node)
 
-	// we was not able to get an address in any of the previous cases:
+	// when an error occurs, it means that we was not able to get an address in any of the previous cases:
 	// 1. no overwrite variable is set
 	// 2. the service is not of type LoadBalancer
 	// 3. there are no nodes in the cluster to get the IP for a NodePort service
-	err = errors.NewNotFound(schema.GroupResource{
-		Group:    apiv1.GroupName,
-		Resource: "nodes",
-	}, "no valid ip")
-	klog.Error(err)
-	return "", err
 }
 
 // get the external port where the Authentication Service is reachable from the external world

pkg/discovery/nodeUtils.go

@@ -0,0 +1,48 @@
+package discovery
+
+import (
+	"fmt"
+
+	v1 "k8s.io/api/core/v1"
+	"k8s.io/klog"
+)
+
+var preferOrder = []v1.NodeAddressType{
+	v1.NodeExternalDNS,
+	v1.NodeExternalIP,
+	v1.NodeInternalDNS,
+	v1.NodeInternalIP,
+	v1.NodeHostName,
+}
+
+// return an address from a Node pool
+func GetAddressFromNodeList(nodes []v1.Node) (string, error) {
+	for _, addrType := range preferOrder {
+		for _, node := range nodes {
+			if addr, err := getAddressByType(&node, addrType); err != nil {
+				klog.V(4).Info(err.Error())
+				continue
+			} else {
+				klog.V(4).Infof("found address %v with type %v", addr, addrType)
+				return addr, nil
+			}
+		}
+	}
+	return "", fmt.Errorf("no address found")
+}
+
+// return an address for a Node
+func GetAddress(node *v1.Node) (string, error) {
+	return GetAddressFromNodeList([]v1.Node{
+		*node,
+	})
+}
+
+func getAddressByType(node *v1.Node, addrType v1.NodeAddressType) (string, error) {
+	for _, addr := range node.Status.Addresses {
+		if addr.Type == addrType {
+			return addr.Address, nil
+		}
+	}
+	return "", fmt.Errorf("no address with type %v found in node %v", addrType, node.Name)
+}

pkg/kubeconfig/create.go

@@ -3,7 +3,9 @@ package kubeconfig
 import (
 	"context"
 	"errors"
+
 	"github.com/liqotech/liqo/pkg/clusterConfig"
+	"github.com/liqotech/liqo/pkg/discovery"
 	corev1 "k8s.io/api/core/v1"
 	v1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/apimachinery/pkg/runtime"
@@ -26,14 +28,19 @@ func CreateKubeConfigFromServiceAccount(apiServerConfigProvider clusterConfig.Ap
 			LabelSelector: "node-role.kubernetes.io/master",
 		})
 		if err != nil {
+			klog.Error(err)
 			return "", err
 		}
-		if len(nodes.Items) == 0 || len(nodes.Items[0].Status.Addresses) == 0 {
+		if len(nodes.Items) == 0 {
 			err = errors.New("no APISERVER env variable found and no master node found, one of the two values must be present")
-			klog.Error(err, err.Error())
+			klog.Error(err)
+			return "", err
+		}
+		address, err = discovery.GetAddressFromNodeList(nodes.Items)
+		if err != nil {
+			klog.Error(err)
 			return "", err
 		}
-		address = nodes.Items[0].Status.Addresses[0].Address
 	}
 
 	port := apiServerConfigProvider.GetApiServerConfig().Port
@@ -54,6 +61,7 @@ func CreateKubeConfigFromServiceAccount(apiServerConfigProvider clusterConfig.Ap
 	cnf := kubeconfigutil.CreateWithToken(server, "service-cluster", serviceAccount.Name, caCrt, token)
 	r, err := runtime.Encode(clientcmdlatest.Codec, cnf)
 	if err != nil {
+		klog.Error(err)
 		return "", err
 	}
 	return string(r), nil