Added Hostname and Subdomain field to Pod.Spec

cluster/addons/dns/README.md

@@ -60,24 +60,55 @@ When enabled, pods are assigned a DNS A record in the form of `pod-ip-address.my
 For example, a pod with ip `1.2.3.4` in the namespace `default` with a dns name of `cluster.local` would have an entry: `1-2-3-4.default.pod.cluster.local`.
 
 
-####A Records and hostname Based on Pod Annotations - A Beta Feature in Kubernetes v1.2
+####A Records and hostname based on Pod's hostname and subdomain fields
 Currently when a pod is created, its hostname is the Pod's `metadata.name` value.
+
 With v1.2, users can specify a Pod annotation, `pod.beta.kubernetes.io/hostname`, to specify what the Pod's hostname should be.
 If the annotation is specified, the annotation value takes precendence over the Pod's name, to be the hostname of the pod.
 For example, given a Pod with annotation `pod.beta.kubernetes.io/hostname: my-pod-name`, the Pod will have its hostname set to "my-pod-name".
 
+With v1.3, the PodSpec has a `hostname` field, which can be used to specify the Pod's hostname. This field value takes precedence over the
+`pod.beta.kubernetes.io/hostname` annotation value.
+
 v1.2 introduces a beta feature where the user can specify a Pod annotation, `pod.beta.kubernetes.io/subdomain`, to specify what the Pod's subdomain should be.
 If the annotation is specified, the fully qualified Pod hostname will be "<hostname>.<subdomain>.<pod namespace>.svc.<cluster domain>".
 For example, given a Pod with the hostname annotation set to "foo", and the subdomain annotation set to "bar", in namespace "my-namespace", the pod will set its own FQDN as "foo.bar.my-namespace.svc.cluster.local"
 
+With v1.3, the PodSpec has a `subdomain` field, which can be used to specify the Pod's subdomain. This field value takes precedence over the
+`pod.beta.kubernetes.io/subdomain` annotation value.
+
+Example:
+
+```yaml
+apiVersion: v1
+kind: Pod
+metadata:
+  name: busybox
+  namespace: default
+spec:
+  hostname: busybox-1
+  subdomain: default
+  containers:
+  - image: busybox
+    command:
+      - sleep
+      - "3600"
+    name: busybox
+```
+
 If there exists a headless service in the same namespace as the pod and with the same name as the subdomain, the cluster's KubeDNS Server will also return an A record for the Pod's fully qualified hostname.
-Given a Pod with the hostname annotation set to "foo" and the subdomain annotation set to "bar", and a headless Service named "bar" in the same namespace, the pod will see it's own FQDN as "foo.bar.my-namespace.svc.cluster.local". DNS will serve an A record at that name, pointing to the Pod's IP.
+Given a Pod with the hostname set to "foo" and the subdomain set to "bar", and a headless Service named "bar" in the same namespace, the pod will see it's own FQDN as "foo.bar.my-namespace.svc.cluster.local". DNS will serve an A record at that name, pointing to the Pod's IP.
 
 With v1.2, the Endpoints object also has a new annotation `endpoints.beta.kubernetes.io/hostnames-map`. Its value is the json representation of map[string(IP)][endpoints.HostRecord], for example: '{"10.245.1.6":{HostName: "my-webserver"}}'.
 If the Endpoints are for a headless service, then A records will be created with the format <hostname>.<service name>.<pod namespace>.svc.<cluster domain>
 For the example json, if endpoints are for a headless service named "bar", and one of the endpoints has IP "10.245.1.6", then a A record will be created with the name "my-webserver.bar.my-namespace.svc.cluster.local" and the A record lookup would return "10.245.1.6".
 This endpoints annotation generally does not need to be specified by end-users, but can used by the internal service controller to deliver the aforementioned feature.
 
+With v1.3, The Endpoints object can specify the `hostname` for any endpoint, along with its IP. The hostname field takes precedence over the hostname value
+that might have been specified via the  `endpoints.beta.kubernetes.io/hostnames-map` annotation.
+
+With v1.3, the following annotations are deprecated: `pod.beta.kubernetes.io/hostname`, `pod.beta.kubernetes.io/subdomain`, `endpoints.beta.kubernetes.io/hostnames-map`
+
 ## How do I find the DNS server?
 The DNS server itself runs as a Kubernetes Service.  This gives it a stable IP
 address.  When you run the SkyDNS service, you want to assign a static IP to use for

cluster/addons/dns/kube2sky/kube2sky.go

@@ -161,28 +161,27 @@ func getSkyMsg(ip string, port int) *skymsg.Service {
 }
 
 func (ks *kube2sky) generateRecordsForHeadlessService(subdomain string, e *kapi.Endpoints, svc *kapi.Service) error {
-	glog.V(4).Infof("Endpoints Annotations: %v", e.Annotations)
+	// TODO: remove this after v1.4 is released and the old annotations are EOL
+	podHostnames, err := getPodHostnamesFromAnnotation(e.Annotations)
+	if err != nil {
+		return err
+	}
 	for idx := range e.Subsets {
 		for subIdx := range e.Subsets[idx].Addresses {
-			endpointIP := e.Subsets[idx].Addresses[subIdx].IP
+			address := &e.Subsets[idx].Addresses[subIdx]
+			endpointIP := address.IP
 			b, err := json.Marshal(getSkyMsg(endpointIP, 0))
 			if err != nil {
 				return err
 			}
 			recordValue := string(b)
-			recordLabel := getHash(recordValue)
-			if serializedPodHostnames := e.Annotations[endpoints.PodHostnamesAnnotation]; len(serializedPodHostnames) > 0 {
-				podHostnames := map[string]endpoints.HostRecord{}
-				err := json.Unmarshal([]byte(serializedPodHostnames), &podHostnames)
-				if err != nil {
-					return err
-				}
-				if hostRecord, exists := podHostnames[string(endpointIP)]; exists {
-					if validation.IsDNS1123Label(hostRecord.HostName) {
-						recordLabel = hostRecord.HostName
-					}
-				}
+			var recordLabel string
+			if hostLabel, exists := getHostname(address, podHostnames); exists {
+				recordLabel = hostLabel
+			} else {
+				recordLabel = getHash(recordValue)
 			}
+
 			recordKey := buildDNSNameString(subdomain, recordLabel)
 
 			glog.V(2).Infof("Setting DNS record: %v -> %q\n", recordKey, recordValue)
@@ -205,6 +204,30 @@ func (ks *kube2sky) generateRecordsForHeadlessService(subdomain string, e *kapi.
 	return nil
 }
 
+func getHostname(address *kapi.EndpointAddress, podHostnames map[string]endpoints.HostRecord) (string, bool) {
+	if len(address.Hostname) > 0 {
+		return address.Hostname, true
+	}
+	if hostRecord, exists := podHostnames[address.IP]; exists && validation.IsDNS1123Label(hostRecord.HostName) {
+		return hostRecord.HostName, true
+	}
+	return "", false
+}
+
+func getPodHostnamesFromAnnotation(annotations map[string]string) (map[string]endpoints.HostRecord, error) {
+	hostnames := map[string]endpoints.HostRecord{}
+
+	if annotations != nil {
+		if serializedHostnames, exists := annotations[endpoints.PodHostnamesAnnotation]; exists && len(serializedHostnames) > 0 {
+			err := json.Unmarshal([]byte(serializedHostnames), &hostnames)
+			if err != nil {
+				return nil, err
+			}
+		}
+	}
+	return hostnames, nil
+}
+
 func (ks *kube2sky) getServiceFromEndpoints(e *kapi.Endpoints) (*kapi.Service, error) {
 	key, err := kcache.MetaNamespaceKeyFunc(e)
 	if err != nil {

cluster/addons/dns/skydns-rc.yaml.in

@@ -50,7 +50,7 @@ spec:
         - name: etcd-storage
           mountPath: /var/etcd/data
       - name: kube2sky
-        image: gcr.io/google_containers/kube2sky:1.14
+        image: gcr.io/google_containers/kube2sky-amd64:1.15
         resources:
           # TODO: Set memory limits when we've profiled the container for large
           # clusters, then set request = limit to keep this container in