Pipe through the ability to set the external hostname for swagger URLs.

cmd/kube-apiserver/app/server.go

@@ -23,6 +23,7 @@ import (
 	"crypto/tls"
 	"net"
 	"net/http"
+	"os"
 	"strconv"
 	"strings"
 	"time"
@@ -45,6 +46,7 @@ import (
 // APIServer runs a kubernetes api server.
 type APIServer struct {
 	WideOpenPort               int
+	ExternalHost               string
 	Address                    util.IP
 	PublicAddressOverride      util.IP
 	ReadOnlyPort               int
@@ -151,6 +153,7 @@ func (s *APIServer) AddFlags(fs *pflag.FlagSet) {
 	client.BindKubeletClientConfigFlags(fs, &s.KubeletConfig)
 	fs.StringVar(&s.ClusterName, "cluster_name", s.ClusterName, "The instance prefix for the cluster")
 	fs.BoolVar(&s.EnableProfiling, "profiling", false, "Enable profiling via web interface host:port/debug/pprof/")
+	fs.StringVar(&s.ExternalHost, "external_hostname", "", "The hostname to use when generating externalized URLs for this master (e.g. Swagger API Docs.)")
 }
 
 // TODO: Longer term we should read this from some config store, rather than a flag.
@@ -227,6 +230,30 @@ func (s *APIServer) Run(_ []string) error {
 	admissionControlPluginNames := strings.Split(s.AdmissionControl, ",")
 	admissionController := admission.NewFromPlugins(client, admissionControlPluginNames, s.AdmissionControlConfigFile)
 
+	if len(s.ExternalHost) == 0 {
+		// TODO: extend for other providers
+		if s.CloudProvider == "gce" {
+			instances, supported := cloud.Instances()
+			if !supported {
+				glog.Fatalf("gce cloud provider has no instances.  this shouldn't happen. exiting.")
+			}
+			name, err := os.Hostname()
+			if err != nil {
+				glog.Fatalf("failed to get hostname: %v", err)
+			}
+			addrs, err := instances.NodeAddresses(name)
+			if err != nil {
+				glog.Warningf("unable to obtain external host address from cloud provider: %v", err)
+			} else {
+				for _, addr := range addrs {
+					if addr.Type == api.NodeExternalIP {
+						s.ExternalHost = addr.Address
+					}
+				}
+			}
+		}
+	}
+
 	config := &master.Config{
 		Cloud:                  cloud,
 		EtcdHelper:             helper,
@@ -249,6 +276,7 @@ func (s *APIServer) Run(_ []string) error {
 		EnableV1Beta3:          v1beta3,
 		MasterServiceNamespace: s.MasterServiceNamespace,
 		ClusterName:            s.ClusterName,
+		ExternalHost:           s.ExternalHost,
 	}
 	m := master.New(config)
 

pkg/master/master.go

@@ -107,6 +107,9 @@ type Config struct {
 	// Defaults to 6443 if not set.
 	ReadWritePort int
 
+	// ExternalHost is the host name to use for external (public internet) facing URLs (e.g. Swagger)
+	ExternalHost string
+
 	// If nil, the first result from net.InterfaceAddrs will be used.
 	PublicAddress net.IP
 
@@ -141,7 +144,10 @@ type Master struct {
 	v1beta3               bool
 	requestContextMapper  api.RequestContextMapper
 
-	publicIP             net.IP
+	// External host is the name that should be used in external (public internet) URLs for this master
+	externalHost string
+	// clusterIP is the IP address of the master within the cluster.
+	clusterIP            net.IP
 	publicReadOnlyPort   int
 	publicReadWritePort  int
 	serviceReadOnlyIP    net.IP
@@ -277,7 +283,8 @@ func New(c *Config) *Master {
 		cacheTimeout: c.CacheTimeout,
 
 		masterCount:         c.MasterCount,
-		publicIP:            c.PublicAddress,
+		externalHost:        c.ExternalHost,
+		clusterIP:           c.PublicAddress,
 		publicReadOnlyPort:  c.ReadOnlyPort,
 		publicReadWritePort: c.ReadWritePort,
 		serviceReadOnlyIP:   serviceReadOnlyIP,
@@ -494,14 +501,23 @@ func (m *Master) init(c *Config) {
 // register their own web services into the Kubernetes mux prior to initialization
 // of swagger, so that other resource types show up in the documentation.
 func (m *Master) InstallSwaggerAPI() {
-	webServicesUrl := ""
-	// Use the secure read write port, if available.
-	if m.publicReadWritePort != 0 {
-		webServicesUrl = "https://" + net.JoinHostPort(m.publicIP.String(), strconv.Itoa(m.publicReadWritePort))
-	} else {
-		// Use the read only port.
-		webServicesUrl = "http://" + net.JoinHostPort(m.publicIP.String(), strconv.Itoa(m.publicReadOnlyPort))
+	hostAndPort := m.externalHost
+	protocol := "https://"
+
+	// TODO: this is kind of messed up, we should just pipe in the full URL from the outside, rather
+	// than guessing at it.
+	if len(m.externalHost) == 0 && m.clusterIP != nil {
+		host := m.clusterIP.String()
+		if m.publicReadWritePort != 0 {
+			hostAndPort = net.JoinHostPort(host, strconv.Itoa(m.publicReadWritePort))
+		} else {
+			// Use the read only port.
+			hostAndPort = net.JoinHostPort(host, strconv.Itoa(m.publicReadOnlyPort))
+			protocol = "http://"
+		}
 	}
+	webServicesUrl := protocol + hostAndPort
+
 	// Enable swagger UI and discovery API
 	swaggerConfig := swagger.Config{
 		WebServicesUrl:  webServicesUrl,

pkg/master/publish.go

@@ -40,7 +40,7 @@ func (m *Master) serviceWriterLoop(stop chan struct{}) {
 			if err := m.createMasterServiceIfNeeded("kubernetes", m.serviceReadWriteIP, m.serviceReadWritePort); err != nil {
 				glog.Errorf("Can't create rw service: %v", err)
 			}
-			if err := m.ensureEndpointsContain("kubernetes", m.publicIP, m.publicReadWritePort); err != nil {
+			if err := m.ensureEndpointsContain("kubernetes", m.clusterIP, m.publicReadWritePort); err != nil {
 				glog.Errorf("Can't create rw endpoints: %v", err)
 			}
 		}
@@ -65,7 +65,7 @@ func (m *Master) roServiceWriterLoop(stop chan struct{}) {
 			if err := m.createMasterServiceIfNeeded("kubernetes-ro", m.serviceReadOnlyIP, m.serviceReadOnlyPort); err != nil {
 				glog.Errorf("Can't create ro service: %v", err)
 			}
-			if err := m.ensureEndpointsContain("kubernetes-ro", m.publicIP, m.publicReadOnlyPort); err != nil {
+			if err := m.ensureEndpointsContain("kubernetes-ro", m.clusterIP, m.publicReadOnlyPort); err != nil {
 				glog.Errorf("Can't create ro endpoints: %v", err)
 			}
 		}