proxy/iptables: don't proxy ExternalName services

pkg/proxy/iptables/proxier.go

@@ -471,6 +471,11 @@ func buildServiceMap(allServices []api.Service, oldServiceMap proxyServiceMap) (
 			glog.V(3).Infof("Skipping service %s due to clusterIP = %q", svcName, service.Spec.ClusterIP)
 			continue
 		}
+		// Even if ClusterIP is set, ServiceTypeExternalName services don't get proxied
+		if service.Spec.Type == api.ServiceTypeExternalName {
+			glog.V(3).Infof("Skipping service %s due to Type=ExternalName", svcName)
+			continue
+		}
 
 		for i := range service.Spec.Ports {
 			servicePort := &service.Spec.Ports[i]

pkg/proxy/iptables/proxier_test.go

@@ -1053,4 +1053,30 @@ func TestBuildServiceMapServiceHeadless(t *testing.T) {
 	}
 }
 
+func TestBuildServiceMapServiceTypeExternalName(t *testing.T) {
+	services := []api.Service{
+		makeTestService("somewhere-else", "external-name", func(svc *api.Service) {
+			svc.Spec.Type = api.ServiceTypeExternalName
+			svc.Spec.ClusterIP = "172.16.55.4" // Should be ignored
+			svc.Spec.ExternalName = "foo2.bar.com"
+			svc.Spec.Ports = addTestPort(svc.Spec.Ports, "blah", "UDP", 1235, 5321, 0)
+		}),
+	}
+
+	serviceMap, hcAdd, hcDel, staleUDPServices := buildServiceMap(services, make(proxyServiceMap))
+	if len(serviceMap) != 0 {
+		t.Errorf("expected service map length 0, got %v", serviceMap)
+	}
+	// No proxied services, so no healthchecks
+	if len(hcAdd) != 0 {
+		t.Errorf("expected healthcheck add length 0, got %v", hcAdd)
+	}
+	if len(hcDel) != 0 {
+		t.Errorf("expected healthcheck del length 0, got %v", hcDel)
+	}
+	if len(staleUDPServices) != 0 {
+		t.Errorf("expected stale UDP services length 0, got %v", staleUDPServices)
+	}
+}
+
 // TODO(thockin): add *more* tests for syncProxyRules() or break it down further and test the pieces.