Check if the dns add-on is working properly and skip invalid TCP services

controllers/nginx-third-party/main.go

@@ -63,14 +63,24 @@ func main() {
 		glog.Fatalf("Please specify --default-backend")
 	}
 
+	glog.Info("Checking if DNS is working")
+	ip, err := checkDNS(*defaultSvc)
+	if err != nil {
+		glog.Fatalf("Please check if the DNS addon is working properly.\n%v", err)
+	}
+	glog.Infof("IP address of '%v' service: %s", *defaultSvc, ip)
+
 	kubeClient, err := unversioned.NewInCluster()
 	if err != nil {
 		glog.Fatalf("failed to create client: %v", err)
 	}
 
 	lbInfo, _ := getLBDetails(kubeClient)
-	defSvc := getService(kubeClient, *defaultSvc)
-	defError := getService(kubeClient, *customErrorSvc)
+	defSvc, err := getService(kubeClient, *defaultSvc)
+	if err != nil {
+		glog.Fatalf("no default backend service found: %v", err)
+	}
+	defError, _ := getService(kubeClient, *customErrorSvc)
 
 	// Start loadbalancer controller
 	lbc, err := NewLoadBalancerController(kubeClient, *resyncPeriod, defSvc, defError, *watchNamespace, lbInfo)

controllers/nginx-third-party/nginx/command.go

@@ -30,6 +30,7 @@ const (
 // Start starts a nginx (master process) and waits. If the process ends
 // we need to kill the controller process and return the reason.
 func (ngx *NginxManager) Start() {
+	glog.Info("Starting nginx...")
 	cmd := exec.Command("nginx")
 	cmd.Stdout = os.Stdout
 	cmd.Stderr = os.Stderr

controllers/nginx-third-party/utils.go

@@ -19,6 +19,7 @@ package main
 import (
 	"encoding/json"
 	"fmt"
+	"net"
 	"os"
 	"strconv"
 	"strings"
@@ -36,6 +37,11 @@ import (
 	"k8s.io/kubernetes/pkg/util/workqueue"
 )
 
+const (
+	httpPort  = "80"
+	httpsPort = "443"
+)
+
 var (
 	errMissingPodInfo = fmt.Errorf("Unable to get POD information")
 
@@ -160,40 +166,35 @@ func getLBDetails(kubeClient *unversioned.Client) (rc *lbInfo, err error) {
 	}
 }
 
-func getService(kubeClient *unversioned.Client, name string) nginx.Service {
+func getService(kubeClient *unversioned.Client, name string) (nginx.Service, error) {
 	if name == "" {
-		return nginx.Service{}
+		return nginx.Service{}, fmt.Errorf("Empty string is not a valid service name")
 	}
 
-	// Wait for the default backend Service. There's no pretty way to do this.
 	parts := strings.Split(name, "/")
 	if len(parts) != 2 {
-		glog.Fatalf("Default backend should take the form namespace/name: %v", name)
+		glog.Fatalf("Please check the service format (namespace/name) in service %v", name)
 	}
 
 	defaultPort, err := getServicePorts(kubeClient, parts[0], parts[1])
 	if err != nil {
-		glog.Fatalf("Could not configure default backend %v: %v", name, err)
+		return nginx.Service{}, fmt.Errorf("Error obtaining service %v: %v", name, err)
 	}
 
 	return nginx.Service{
 		ServiceName: parts[1],
 		ServicePort: defaultPort[0], //TODO: which port?
 		Namespace:   parts[0],
-	}
+	}, nil
 }
 
-// getServicePorts returns the po
+// getServicePorts returns the ports defined in a service spec
 func getServicePorts(kubeClient *unversioned.Client, ns, name string) (ports []string, err error) {
 	var svc *api.Service
-	glog.Infof("Waiting for %v/%v", ns, name)
-	wait.Poll(1*time.Second, 5*time.Minute, func() (bool, error) {
+	glog.Infof("Checking service %v/%v", ns, name)
 	svc, err = kubeClient.Services(ns).Get(name)
 	if err != nil {
-			if glog.V(2) {
-				glog.Errorf("%v", err)
-			}
-			return false, nil
+		return
 	}
 
 	for _, p := range svc.Spec.Ports {
@@ -204,8 +205,6 @@ func getServicePorts(kubeClient *unversioned.Client, ns, name string) (ports []s
 	}
 
 	glog.Infof("Ports for %v/%v : %v", ns, name, ports)
-		return true, nil
-	})
 
 	return
 }
@@ -219,7 +218,18 @@ func getTcpServices(kubeClient *unversioned.Client, tcpServices string) []nginx.
 
 		namePort := strings.Split(svc, ":")
 		if len(namePort) == 2 {
-			tcpSvc := getService(kubeClient, namePort[0])
+			tcpSvc, err := getService(kubeClient, namePort[0])
+			if err != nil {
+				glog.Errorf("%s", err)
+				continue
+			}
+
+			// the exposed TCP service cannot use 80 or 443 as ports
+			if namePort[1] == httpPort || namePort[1] == httpsPort {
+				glog.Errorf("The TCP service %v cannot use ports 80 or 443 (it creates a conflict with nginx)", svc)
+				continue
+			}
+
 			tcpSvc.ExposedPort = namePort[1]
 			svcs = append(svcs, tcpSvc)
 		} else {
@@ -229,3 +239,13 @@ func getTcpServices(kubeClient *unversioned.Client, tcpServices string) []nginx.
 
 	return svcs
 }
+
+func checkDNS(name string) (*net.IPAddr, error) {
+	parts := strings.Split(name, "/")
+	if len(parts) != 2 {
+		glog.Fatalf("Please check the service format (namespace/name) in service %v", name)
+	}
+
+	host := fmt.Sprintf("%v.%v", parts[1], parts[0])
+	return net.ResolveIPAddr("ip4", host)
+}