Kubernetes support externalname service

docs/user-guide/kubernetes.md

@@ -428,3 +428,59 @@ You should now be able to visit the websites in your browser.
 * [cheeses.local/stilton](http://cheeses.local/stilton/)
 * [cheeses.local/cheddar](http://cheeses.local/cheddar/)
 * [cheeses.local/wensleydale](http://cheeses.local/wensleydale/)
+
+## Disable passing the Host header
+By default Træfɪk will pass the incoming Host header on to the upstream resource. There
+are times however where you may not want this to be the case. For example if your service
+is of the ExternalName type.
+
+### Disable entirely
+Add the following to your toml config:
+```toml
+disablePassHostHeaders = true
+```
+
+### Disable per ingress
+To disable passing the Host header per ingress resource set the "traefik.frontend.passHostHeader"
+annotation on your ingress to "false".
+
+Here is an example ingress definition:
+```yaml
+apiVersion: extensions/v1beta1
+kind: Ingress
+metadata:
+  name: example
+  annotations:
+    traefik.frontend.passHostHeader: "false"
+spec:
+  rules:
+  - host: example.com
+    http:
+      paths:
+      - path: /static
+        backend:
+          serviceName: static
+          servicePort: https
+```
+
+And an example service definition:
+```yaml
+apiVersion: v1
+kind: Service
+metadata:
+  name: static
+spec:
+  ports:
+  - name: https
+    port: 443
+  type: ExternalName
+  externalName: static.otherdomain.com
+```
+
+If you were to visit example.com/static the request would then be passed onto
+static.otherdomain.com/static and static.otherdomain.com would receive the
+request with the Host header being static.otherdomain.com.
+
+Note: The per ingress annotation overides whatever the global value is set to. So you
+could set `disablePassHostHeaders` to true in your toml file and then enable passing
+the host header per ingress if you wanted.

provider/kubernetes.go

@@ -107,7 +107,6 @@ func (provider *Kubernetes) loadIngresses(k8sClient k8s.Client) (*types.Configur
 		map[string]*types.Backend{},
 		map[string]*types.Frontend{},
 	}
-	PassHostHeader := provider.getPassHostHeader()
 	for _, i := range ingresses {
 		for _, r := range i.Spec.Rules {
 			if r.HTTP == nil {
@@ -124,6 +123,19 @@ func (provider *Kubernetes) loadIngresses(k8sClient k8s.Client) (*types.Configur
 						},
 					}
 				}
+
+				PassHostHeader := provider.getPassHostHeader()
+
+				passHostHeaderAnnotation := i.Annotations["traefik.frontend.passHostHeader"]
+				switch passHostHeaderAnnotation {
+				case "true":
+					PassHostHeader = true
+				case "false":
+					PassHostHeader = false
+				default:
+					log.Warnf("Unknown value of %s for traefik.frontend.passHostHeader, falling back to %s", passHostHeaderAnnotation, PassHostHeader)
+				}
+
 				if _, exists := templateObjects.Frontends[r.Host+pa.Path]; !exists {
 					templateObjects.Frontends[r.Host+pa.Path] = &types.Frontend{
 						Backend:        r.Host + pa.Path,
@@ -193,28 +205,44 @@ func (provider *Kubernetes) loadIngresses(k8sClient k8s.Client) (*types.Configur
 						if port.Port == 443 {
 							protocol = "https"
 						}
-						endpoints, exists, err := k8sClient.GetEndpoints(service.ObjectMeta.Namespace, service.ObjectMeta.Name)
-						if err != nil || !exists {
-							log.Errorf("Error retrieving endpoints %s/%s: %v", service.ObjectMeta.Namespace, service.ObjectMeta.Name, err)
-							continue
-						}
-						if len(endpoints.Subsets) == 0 {
-							log.Warnf("Endpoints not found for %s/%s, falling back to Service ClusterIP", service.ObjectMeta.Namespace, service.ObjectMeta.Name)
-							templateObjects.Backends[r.Host+pa.Path].Servers[string(service.UID)] = types.Server{
-								URL:    protocol + "://" + service.Spec.ClusterIP + ":" + strconv.Itoa(int(port.Port)),
+						if service.Spec.Type == "ExternalName" {
+							url := protocol + "://" + service.Spec.ExternalName
+							name := url
+
+							templateObjects.Backends[r.Host+pa.Path].Servers[name] = types.Server{
+								URL:    url,
 								Weight: 1,
 							}
 						} else {
-							for _, subset := range endpoints.Subsets {
-								for _, address := range subset.Addresses {
-									url := protocol + "://" + address.IP + ":" + strconv.Itoa(endpointPortNumber(port, subset.Ports))
-									name := url
-									if address.TargetRef != nil && address.TargetRef.Name != "" {
-										name = address.TargetRef.Name
-									}
-									templateObjects.Backends[r.Host+pa.Path].Servers[name] = types.Server{
-										URL:    url,
-										Weight: 1,
+							endpoints, exists, err := k8sClient.GetEndpoints(service.ObjectMeta.Namespace, service.ObjectMeta.Name)
+							if err != nil {
+								log.Errorf("Error while retrieving endpoints from k8s API %s/%s: %v", service.ObjectMeta.Namespace, service.ObjectMeta.Name, err)
+								continue
+							}
+
+							if !exists {
+								log.Errorf("Service not found for %s/%s", service.ObjectMeta.Namespace, service.ObjectMeta.Name)
+								continue
+							}
+
+							if len(endpoints.Subsets) == 0 {
+								log.Warnf("Endpoints not found for %s/%s, falling back to Service ClusterIP", service.ObjectMeta.Namespace, service.ObjectMeta.Name)
+								templateObjects.Backends[r.Host+pa.Path].Servers[string(service.UID)] = types.Server{
+									URL:    protocol + "://" + service.Spec.ClusterIP + ":" + strconv.Itoa(int(port.Port)),
+									Weight: 1,
+								}
+							} else {
+								for _, subset := range endpoints.Subsets {
+									for _, address := range subset.Addresses {
+										url := protocol + "://" + address.IP + ":" + strconv.Itoa(endpointPortNumber(port, subset.Ports))
+										name := url
+										if address.TargetRef != nil && address.TargetRef.Name != "" {
+											name = address.TargetRef.Name
+										}
+										templateObjects.Backends[r.Host+pa.Path].Servers[name] = types.Server{
+											URL:    url,
+											Weight: 1,
+										}
 									}
 								}
 							}