From c28cdfbd431256a88a4cb117abcf67309fb26393 Mon Sep 17 00:00:00 2001
From: Justin Santa Barbara <justin@fathomdb.com>
Date: Fri, 12 Jun 2015 11:40:34 -0400
Subject: [PATCH 1/4] For kubelet, differentiate between the nodeName and the
 hostname

This will allow us to use a nodeName that is not the hostname,
for example on clouds where the hostname is not the natural identifier
for a node.
---
 cmd/kubelet/app/server.go       | 12 ++++++---
 pkg/kubelet/config/apiserver.go |  4 +--
 pkg/kubelet/config/common.go    | 14 +++++------
 pkg/kubelet/config/file.go      |  8 +++---
 pkg/kubelet/config/http.go      |  8 +++---
 pkg/kubelet/kubelet.go          | 43 ++++++++++++++++++---------------
 6 files changed, 49 insertions(+), 40 deletions(-)

diff --git a/cmd/kubelet/app/server.go b/cmd/kubelet/app/server.go
index 241b835e0e6..995a567b11b 100644
--- a/cmd/kubelet/app/server.go
+++ b/cmd/kubelet/app/server.go
@@ -565,8 +565,10 @@ func SimpleKubelet(client *client.Client,
 // Eventually, #2 will be replaced with instances of #3
 func RunKubelet(kcfg *KubeletConfig, builder KubeletBuilder) error {
 	kcfg.Hostname = nodeutil.GetHostname(kcfg.HostnameOverride)
+	kcfg.NodeName = kcfg.Hostname
+
 	eventBroadcaster := record.NewBroadcaster()
-	kcfg.Recorder = eventBroadcaster.NewRecorder(api.EventSource{Component: "kubelet", Host: kcfg.Hostname})
+	kcfg.Recorder = eventBroadcaster.NewRecorder(api.EventSource{Component: "kubelet", Host: kcfg.NodeName})
 	eventBroadcaster.StartLogging(glog.Infof)
 	if kcfg.KubeClient != nil {
 		glog.V(4).Infof("Sending events to api server.")
@@ -625,17 +627,17 @@ func makePodSourceConfig(kc *KubeletConfig) *config.PodConfig {
 	// define file config source
 	if kc.ConfigFile != "" {
 		glog.Infof("Adding manifest file: %v", kc.ConfigFile)
-		config.NewSourceFile(kc.ConfigFile, kc.Hostname, kc.FileCheckFrequency, cfg.Channel(kubelet.FileSource))
+		config.NewSourceFile(kc.ConfigFile, kc.NodeName, kc.FileCheckFrequency, cfg.Channel(kubelet.FileSource))
 	}
 
 	// define url config source
 	if kc.ManifestURL != "" {
 		glog.Infof("Adding manifest url: %v", kc.ManifestURL)
-		config.NewSourceURL(kc.ManifestURL, kc.Hostname, kc.HTTPCheckFrequency, cfg.Channel(kubelet.HTTPSource))
+		config.NewSourceURL(kc.ManifestURL, kc.NodeName, kc.HTTPCheckFrequency, cfg.Channel(kubelet.HTTPSource))
 	}
 	if kc.KubeClient != nil {
 		glog.Infof("Watching apiserver")
-		config.NewSourceApiserver(kc.KubeClient, kc.Hostname, cfg.Channel(kubelet.ApiserverSource))
+		config.NewSourceApiserver(kc.KubeClient, kc.NodeName, cfg.Channel(kubelet.ApiserverSource))
 	}
 	return cfg
 }
@@ -656,6 +658,7 @@ type KubeletConfig struct {
 	FileCheckFrequency             time.Duration
 	HTTPCheckFrequency             time.Duration
 	Hostname                       string
+	NodeName                       string
 	PodInfraContainerImage         string
 	SyncFrequency                  time.Duration
 	RegistryPullQPS                float64
@@ -715,6 +718,7 @@ func createAndInitKubelet(kc *KubeletConfig) (k KubeletBootstrap, pc *config.Pod
 	pc = makePodSourceConfig(kc)
 	k, err = kubelet.NewMainKubelet(
 		kc.Hostname,
+		kc.NodeName,
 		kc.DockerClient,
 		kubeClient,
 		kc.RootDirectory,
diff --git a/pkg/kubelet/config/apiserver.go b/pkg/kubelet/config/apiserver.go
index 56794ca3e74..88bb84b48a0 100644
--- a/pkg/kubelet/config/apiserver.go
+++ b/pkg/kubelet/config/apiserver.go
@@ -26,8 +26,8 @@ import (
 )
 
 // NewSourceApiserver creates a config source that watches and pulls from the apiserver.
-func NewSourceApiserver(c *client.Client, hostname string, updates chan<- interface{}) {
-	lw := cache.NewListWatchFromClient(c, "pods", api.NamespaceAll, fields.OneTermEqualSelector(client.PodHost, hostname))
+func NewSourceApiserver(c *client.Client, nodeName string, updates chan<- interface{}) {
+	lw := cache.NewListWatchFromClient(c, "pods", api.NamespaceAll, fields.OneTermEqualSelector(client.PodHost, nodeName))
 	newSourceApiserverFromLW(lw, updates)
 }
 
diff --git a/pkg/kubelet/config/common.go b/pkg/kubelet/config/common.go
index b757bba3aa7..d5a4bd42799 100644
--- a/pkg/kubelet/config/common.go
+++ b/pkg/kubelet/config/common.go
@@ -33,16 +33,16 @@ import (
 	"github.com/golang/glog"
 )
 
-// Generate a pod name that is unique among nodes by appending the hostname.
-func generatePodName(name, hostname string) string {
-	return fmt.Sprintf("%s-%s", name, hostname)
+// Generate a pod name that is unique among nodes by appending the nodeName.
+func generatePodName(name, nodeName string) string {
+	return fmt.Sprintf("%s-%s", name, nodeName)
 }
 
-func applyDefaults(pod *api.Pod, source string, isFile bool, hostname string) error {
+func applyDefaults(pod *api.Pod, source string, isFile bool, nodeName string) error {
 	if len(pod.UID) == 0 {
 		hasher := md5.New()
 		if isFile {
-			fmt.Fprintf(hasher, "host:%s", hostname)
+			fmt.Fprintf(hasher, "host:%s", nodeName)
 			fmt.Fprintf(hasher, "file:%s", source)
 		} else {
 			fmt.Fprintf(hasher, "url:%s", source)
@@ -57,7 +57,7 @@ func applyDefaults(pod *api.Pod, source string, isFile bool, hostname string) er
 	if len(pod.Name) == 0 {
 		pod.Name = string(pod.UID)
 	}
-	pod.Name = generatePodName(pod.Name, hostname)
+	pod.Name = generatePodName(pod.Name, nodeName)
 	glog.V(5).Infof("Generated Name %q for UID %q from URL %s", pod.Name, pod.UID, source)
 
 	if pod.Namespace == "" {
@@ -66,7 +66,7 @@ func applyDefaults(pod *api.Pod, source string, isFile bool, hostname string) er
 	glog.V(5).Infof("Using namespace %q for pod %q from %s", pod.Namespace, pod.Name, source)
 
 	// Set the Host field to indicate this pod is scheduled on the current node.
-	pod.Spec.NodeName = hostname
+	pod.Spec.NodeName = nodeName
 
 	pod.ObjectMeta.SelfLink = getSelfLink(pod.Name, pod.Namespace)
 	return nil
diff --git a/pkg/kubelet/config/file.go b/pkg/kubelet/config/file.go
index 3ef6a17f877..3d73010dd2e 100644
--- a/pkg/kubelet/config/file.go
+++ b/pkg/kubelet/config/file.go
@@ -34,14 +34,14 @@ import (
 
 type sourceFile struct {
 	path     string
-	hostname string
+	nodeName string
 	updates  chan<- interface{}
 }
 
-func NewSourceFile(path string, hostname string, period time.Duration, updates chan<- interface{}) {
+func NewSourceFile(path string, nodeName string, period time.Duration, updates chan<- interface{}) {
 	config := &sourceFile{
 		path:     path,
-		hostname: hostname,
+		nodeName: nodeName,
 		updates:  updates,
 	}
 	glog.V(1).Infof("Watching path %q", path)
@@ -55,7 +55,7 @@ func (s *sourceFile) run() {
 }
 
 func (s *sourceFile) applyDefaults(pod *api.Pod, source string) error {
-	return applyDefaults(pod, source, true, s.hostname)
+	return applyDefaults(pod, source, true, s.nodeName)
 }
 
 func (s *sourceFile) extractFromPath() error {
diff --git a/pkg/kubelet/config/http.go b/pkg/kubelet/config/http.go
index e8d69f85290..de536ae3b74 100644
--- a/pkg/kubelet/config/http.go
+++ b/pkg/kubelet/config/http.go
@@ -33,15 +33,15 @@ import (
 
 type sourceURL struct {
 	url      string
-	hostname string
+	nodeName string
 	updates  chan<- interface{}
 	data     []byte
 }
 
-func NewSourceURL(url, hostname string, period time.Duration, updates chan<- interface{}) {
+func NewSourceURL(url, nodeName string, period time.Duration, updates chan<- interface{}) {
 	config := &sourceURL{
 		url:      url,
-		hostname: hostname,
+		nodeName: nodeName,
 		updates:  updates,
 		data:     nil,
 	}
@@ -56,7 +56,7 @@ func (s *sourceURL) run() {
 }
 
 func (s *sourceURL) applyDefaults(pod *api.Pod) error {
-	return applyDefaults(pod, s.url, false, s.hostname)
+	return applyDefaults(pod, s.url, false, s.nodeName)
 }
 
 func (s *sourceURL) extractFromURL() error {
diff --git a/pkg/kubelet/kubelet.go b/pkg/kubelet/kubelet.go
index 6d88c53001a..d1070cc390b 100644
--- a/pkg/kubelet/kubelet.go
+++ b/pkg/kubelet/kubelet.go
@@ -114,6 +114,7 @@ func waitUntilRuntimeIsUp(cr kubecontainer.Runtime, timeout time.Duration) error
 // New creates a new Kubelet for use in main
 func NewMainKubelet(
 	hostname string,
+	nodeName string,
 	dockerClient dockertools.DockerInterface,
 	kubeClient client.Interface,
 	rootDirectory string,
@@ -179,7 +180,7 @@ func NewMainKubelet(
 	if kubeClient != nil {
 		// TODO: cache.NewListWatchFromClient is limited as it takes a client implementation rather
 		// than an interface. There is no way to construct a list+watcher using resource name.
-		fieldSelector := fields.Set{client.ObjectNameField: hostname}.AsSelector()
+		fieldSelector := fields.Set{client.ObjectNameField: nodeName}.AsSelector()
 		listWatch := &cache.ListWatch{
 			ListFunc: func() (runtime.Object, error) {
 				return kubeClient.Nodes().List(labels.Everything(), fieldSelector)
@@ -197,8 +198,8 @@ func NewMainKubelet(
 	// TODO: what is namespace for node?
 	nodeRef := &api.ObjectReference{
 		Kind:      "Node",
-		Name:      hostname,
-		UID:       types.UID(hostname),
+		Name:      nodeName,
+		UID:       types.UID(nodeName),
 		Namespace: "",
 	}
 
@@ -224,6 +225,7 @@ func NewMainKubelet(
 
 	klet := &Kubelet{
 		hostname:                       hostname,
+		nodeName:                       nodeName,
 		dockerClient:                   dockerClient,
 		kubeClient:                     kubeClient,
 		rootDirectory:                  rootDirectory,
@@ -362,6 +364,7 @@ type nodeLister interface {
 // Kubelet is the main kubelet implementation.
 type Kubelet struct {
 	hostname       string
+	nodeName       string
 	dockerClient   dockertools.DockerInterface
 	runtimeCache   kubecontainer.RuntimeCache
 	kubeClient     client.Interface
@@ -637,13 +640,13 @@ func (kl *Kubelet) GetNode() (*api.Node, error) {
 	if err != nil {
 		return nil, errors.New("cannot list nodes")
 	}
-	host := kl.GetHostname()
+	nodeName := kl.nodeName
 	for _, n := range l.Items {
-		if n.Name == host {
+		if n.Name == nodeName {
 			return &n, nil
 		}
 	}
-	return nil, fmt.Errorf("node %v not found", host)
+	return nil, fmt.Errorf("node %v not found", nodeName)
 }
 
 // Starts garbage collection theads.
@@ -709,7 +712,7 @@ func (kl *Kubelet) Run(updates <-chan PodUpdate) {
 func (kl *Kubelet) initialNodeStatus() (*api.Node, error) {
 	node := &api.Node{
 		ObjectMeta: api.ObjectMeta{
-			Name:   kl.hostname,
+			Name:   kl.nodeName,
 			Labels: map[string]string{"kubernetes.io/hostname": kl.hostname},
 		},
 	}
@@ -718,18 +721,20 @@ func (kl *Kubelet) initialNodeStatus() (*api.Node, error) {
 		if !ok {
 			return nil, fmt.Errorf("failed to get instances from cloud provider")
 		}
+
 		// TODO(roberthbailey): Can we do this without having credentials to talk
 		// to the cloud provider?
 		// TODO: ExternalID is deprecated, we'll have to drop this code
-		externalID, err := instances.ExternalID(kl.hostname)
+		externalID, err := instances.ExternalID(kl.nodeName)
 		if err != nil {
 			return nil, fmt.Errorf("failed to get external ID from cloud provider: %v", err)
 		}
 		node.Spec.ExternalID = externalID
+
 		// TODO: We can't assume that the node has credentials to talk to the
 		// cloudprovider from arbitrary nodes. At most, we should talk to a
 		// local metadata server here.
-		node.Spec.ProviderID, err = cloudprovider.GetInstanceProviderID(kl.cloud, kl.hostname)
+		node.Spec.ProviderID, err = cloudprovider.GetInstanceProviderID(kl.cloud, kl.nodeName)
 		if err != nil {
 			return nil, err
 		}
@@ -760,13 +765,13 @@ func (kl *Kubelet) registerWithApiserver() {
 		glog.V(2).Infof("Attempting to register node %s", node.Name)
 		if _, err := kl.kubeClient.Nodes().Create(node); err != nil {
 			if apierrors.IsAlreadyExists(err) {
-				currentNode, err := kl.kubeClient.Nodes().Get(kl.hostname)
+				currentNode, err := kl.kubeClient.Nodes().Get(kl.nodeName)
 				if err != nil {
-					glog.Errorf("error getting node %q: %v", kl.hostname, err)
+					glog.Errorf("error getting node %q: %v", kl.nodeName, err)
 					continue
 				}
 				if currentNode == nil {
-					glog.Errorf("no node instance returned for %q", kl.hostname)
+					glog.Errorf("no node instance returned for %q", kl.nodeName)
 					continue
 				}
 				if currentNode.Spec.ExternalID == node.Spec.ExternalID {
@@ -1824,10 +1829,10 @@ func (kl *Kubelet) updateNodeStatus() error {
 }
 
 func (kl *Kubelet) recordNodeStatusEvent(event string) {
-	glog.V(2).Infof("Recording %s event message for node %s", event, kl.hostname)
+	glog.V(2).Infof("Recording %s event message for node %s", event, kl.nodeName)
 	// TODO: This requires a transaction, either both node status is updated
 	// and event is recorded or neither should happen, see issue #6055.
-	kl.recorder.Eventf(kl.nodeRef, event, "Node %s status is now: %s", kl.hostname, event)
+	kl.recorder.Eventf(kl.nodeRef, event, "Node %s status is now: %s", kl.nodeName, event)
 }
 
 // Maintains Node.Spec.Unschedulable value from previous run of tryUpdateNodeStatus()
@@ -1844,7 +1849,7 @@ func (kl *Kubelet) setNodeStatus(node *api.Node) error {
 		}
 		// TODO(roberthbailey): Can we do this without having credentials to talk
 		// to the cloud provider?
-		nodeAddresses, err := instances.NodeAddresses(kl.hostname)
+		nodeAddresses, err := instances.NodeAddresses(kl.nodeName)
 		if err != nil {
 			return fmt.Errorf("failed to get node address from cloud provider: %v", err)
 		}
@@ -1898,7 +1903,7 @@ func (kl *Kubelet) setNodeStatus(node *api.Node) error {
 			// TODO: This requires a transaction, either both node status is updated
 			// and event is recorded or neither should happen, see issue #6055.
 			kl.recorder.Eventf(kl.nodeRef, "rebooted",
-				"Node %s has been rebooted, boot id: %s", kl.hostname, info.BootID)
+				"Node %s has been rebooted, boot id: %s", kl.nodeName, info.BootID)
 		}
 		node.Status.NodeInfo.BootID = info.BootID
 	}
@@ -1987,12 +1992,12 @@ func (kl *Kubelet) setNodeStatus(node *api.Node) error {
 // tryUpdateNodeStatus tries to update node status to master. If ReconcileCBR0
 // is set, this function will also confirm that cbr0 is configured correctly.
 func (kl *Kubelet) tryUpdateNodeStatus() error {
-	node, err := kl.kubeClient.Nodes().Get(kl.hostname)
+	node, err := kl.kubeClient.Nodes().Get(kl.nodeName)
 	if err != nil {
-		return fmt.Errorf("error getting node %q: %v", kl.hostname, err)
+		return fmt.Errorf("error getting node %q: %v", kl.nodeName, err)
 	}
 	if node == nil {
-		return fmt.Errorf("no node instance returned for %q", kl.hostname)
+		return fmt.Errorf("no node instance returned for %q", kl.nodeName)
 	}
 	if err := kl.setNodeStatus(node); err != nil {
 		return err

From efaead81dc7220e3921ede18358aca5d6c566c19 Mon Sep 17 00:00:00 2001
From: Justin Santa Barbara <justin@fathomdb.com>
Date: Fri, 12 Jun 2015 11:42:38 -0400
Subject: [PATCH 2/4] Allow cloud providers to return a node identifier
 different from the hostname

---
 cmd/kubelet/app/server.go                | 22 +++++++++++++++++++++-
 pkg/cloudprovider/aws/aws.go             |  4 ++++
 pkg/cloudprovider/cloud.go               |  3 +++
 pkg/cloudprovider/fake/fake.go           |  5 +++++
 pkg/cloudprovider/gce/gce.go             |  5 +++++
 pkg/cloudprovider/mesos/mesos.go         |  5 +++++
 pkg/cloudprovider/openstack/openstack.go |  5 +++++
 pkg/cloudprovider/ovirt/ovirt.go         |  5 +++++
 pkg/cloudprovider/rackspace/rackspace.go |  5 +++++
 pkg/cloudprovider/vagrant/vagrant.go     |  5 +++++
 pkg/kubelet/kubelet.go                   |  1 +
 11 files changed, 64 insertions(+), 1 deletion(-)

diff --git a/cmd/kubelet/app/server.go b/cmd/kubelet/app/server.go
index 995a567b11b..4d67bbb1d7c 100644
--- a/cmd/kubelet/app/server.go
+++ b/cmd/kubelet/app/server.go
@@ -565,7 +565,27 @@ func SimpleKubelet(client *client.Client,
 // Eventually, #2 will be replaced with instances of #3
 func RunKubelet(kcfg *KubeletConfig, builder KubeletBuilder) error {
 	kcfg.Hostname = nodeutil.GetHostname(kcfg.HostnameOverride)
-	kcfg.NodeName = kcfg.Hostname
+
+	if kcfg.NodeName == "" {
+		// Query the cloud provider for our node name, default to Hostname
+		nodeName := kcfg.Hostname
+		if kcfg.Cloud != nil {
+			var err error
+			instances, ok := kcfg.Cloud.Instances()
+			if !ok {
+				return fmt.Errorf("failed to get instances from cloud provider")
+			}
+
+			nodeName, err = instances.CurrentNodeName(kcfg.Hostname)
+			if err != nil {
+				return fmt.Errorf("error fetching current instance name from cloud provider: %v", err)
+			}
+
+			glog.V(2).Infof("cloud provider determined current node name to be %s", nodeName)
+		}
+
+		kcfg.NodeName = nodeName
+	}
 
 	eventBroadcaster := record.NewBroadcaster()
 	kcfg.Recorder = eventBroadcaster.NewRecorder(api.EventSource{Component: "kubelet", Host: kcfg.NodeName})
diff --git a/pkg/cloudprovider/aws/aws.go b/pkg/cloudprovider/aws/aws.go
index 4a899966b42..c6a9d099ebf 100644
--- a/pkg/cloudprovider/aws/aws.go
+++ b/pkg/cloudprovider/aws/aws.go
@@ -234,6 +234,10 @@ func (self *AWSCloud) AddSSHKeyToAllInstances(user string, keyData []byte) error
 	return errors.New("unimplemented")
 }
 
+func (a *AWSCloud) CurrentNodeName(hostname string) (string, error) {
+	return hostname, nil
+}
+
 // Implementation of EC2.Instances
 func (self *awsSdkEC2) DescribeInstances(request *ec2.DescribeInstancesInput) ([]*ec2.Instance, error) {
 	// Instances are paged
diff --git a/pkg/cloudprovider/cloud.go b/pkg/cloudprovider/cloud.go
index e5d371ffeb3..3e0d50086ab 100644
--- a/pkg/cloudprovider/cloud.go
+++ b/pkg/cloudprovider/cloud.go
@@ -111,6 +111,9 @@ type Instances interface {
 	// AddSSHKeyToAllInstances adds an SSH public key as a legal identity for all instances
 	// expected format for the key is standard ssh-keygen format: <protocol> <blob>
 	AddSSHKeyToAllInstances(user string, keyData []byte) error
+	// Returns the name of the node we are currently running on
+	// On most clouds (e.g. GCE) this is the hostname, so we provide the hostname
+	CurrentNodeName(hostname string) (string, error)
 }
 
 // Route is a representation of an advanced routing rule.
diff --git a/pkg/cloudprovider/fake/fake.go b/pkg/cloudprovider/fake/fake.go
index ed81d523899..96f39e3abde 100644
--- a/pkg/cloudprovider/fake/fake.go
+++ b/pkg/cloudprovider/fake/fake.go
@@ -149,6 +149,11 @@ func (f *FakeCloud) AddSSHKeyToAllInstances(user string, keyData []byte) error {
 	return errors.New("unimplemented")
 }
 
+// Implementation of Instances.CurrentNodeName
+func (f *FakeCloud) CurrentNodeName(hostname string) (string, error) {
+	return hostname, nil
+}
+
 // NodeAddresses is a test-spy implementation of Instances.NodeAddresses.
 // It adds an entry "node-addresses" into the internal method call record.
 func (f *FakeCloud) NodeAddresses(instance string) ([]api.NodeAddress, error) {
diff --git a/pkg/cloudprovider/gce/gce.go b/pkg/cloudprovider/gce/gce.go
index d7cdb8a8d05..13be7164bb0 100644
--- a/pkg/cloudprovider/gce/gce.go
+++ b/pkg/cloudprovider/gce/gce.go
@@ -483,6 +483,11 @@ func (gce *GCECloud) getInstanceByName(name string) (*compute.Instance, error) {
 	return res, nil
 }
 
+// Implementation of Instances.CurrentNodeName
+func (gce *GCECloud) CurrentNodeName(hostname string) (string, error) {
+	return hostname, nil
+}
+
 func (gce *GCECloud) AddSSHKeyToAllInstances(user string, keyData []byte) error {
 	return wait.Poll(2*time.Second, 30*time.Second, func() (bool, error) {
 		project, err := gce.service.Projects.Get(gce.projectID).Do()
diff --git a/pkg/cloudprovider/mesos/mesos.go b/pkg/cloudprovider/mesos/mesos.go
index 600c9050ac3..266fd80f989 100644
--- a/pkg/cloudprovider/mesos/mesos.go
+++ b/pkg/cloudprovider/mesos/mesos.go
@@ -78,6 +78,11 @@ func newMesosCloud(configReader io.Reader) (*MesosCloud, error) {
 	}
 }
 
+// Implementation of Instances.CurrentNodeName
+func (c *MesosCloud) CurrentNodeName(hostname string) (string, error) {
+	return hostname, nil
+}
+
 func (c *MesosCloud) AddSSHKeyToAllInstances(user string, keyData []byte) error {
 	return errors.New("unimplemented")
 }
diff --git a/pkg/cloudprovider/openstack/openstack.go b/pkg/cloudprovider/openstack/openstack.go
index c4349ebf09d..f0ed6f0e7d7 100644
--- a/pkg/cloudprovider/openstack/openstack.go
+++ b/pkg/cloudprovider/openstack/openstack.go
@@ -317,6 +317,11 @@ func getAddressByName(api *gophercloud.ServiceClient, name string) (string, erro
 	return s, nil
 }
 
+// Implementation of Instances.CurrentNodeName
+func (i *Instances) CurrentNodeName(hostname string) (string, error) {
+	return hostname, nil
+}
+
 func (i *Instances) AddSSHKeyToAllInstances(user string, keyData []byte) error {
 	return errors.New("unimplemented")
 }
diff --git a/pkg/cloudprovider/ovirt/ovirt.go b/pkg/cloudprovider/ovirt/ovirt.go
index abcfff64539..6b4682411df 100644
--- a/pkg/cloudprovider/ovirt/ovirt.go
+++ b/pkg/cloudprovider/ovirt/ovirt.go
@@ -275,6 +275,11 @@ func (v *OVirtCloud) GetNodeResources(name string) (*api.NodeResources, error) {
 	return nil, nil
 }
 
+// Implementation of Instances.CurrentNodeName
+func (v *OVirtCloud) CurrentNodeName(hostname string) (string, error) {
+	return hostname, nil
+}
+
 func (v *OVirtCloud) AddSSHKeyToAllInstances(user string, keyData []byte) error {
 	return errors.New("unimplemented")
 }
diff --git a/pkg/cloudprovider/rackspace/rackspace.go b/pkg/cloudprovider/rackspace/rackspace.go
index 38f2c25ebaf..e3fc2b4f3b2 100644
--- a/pkg/cloudprovider/rackspace/rackspace.go
+++ b/pkg/cloudprovider/rackspace/rackspace.go
@@ -380,6 +380,11 @@ func (i *Instances) AddSSHKeyToAllInstances(user string, keyData []byte) error {
 	return errors.New("unimplemented")
 }
 
+// Implementation of Instances.CurrentNodeName
+func (i *Instances) CurrentNodeName(hostname string) (string, error) {
+	return hostname, nil
+}
+
 func (i *Instances) GetNodeResources(name string) (*api.NodeResources, error) {
 	glog.V(2).Infof("GetNodeResources(%v) called", name)
 
diff --git a/pkg/cloudprovider/vagrant/vagrant.go b/pkg/cloudprovider/vagrant/vagrant.go
index e4e89ed453e..ed0bf2c91e9 100644
--- a/pkg/cloudprovider/vagrant/vagrant.go
+++ b/pkg/cloudprovider/vagrant/vagrant.go
@@ -135,6 +135,11 @@ func (v *VagrantCloud) AddSSHKeyToAllInstances(user string, keyData []byte) erro
 	return errors.New("unimplemented")
 }
 
+// Implementation of Instances.CurrentNodeName
+func (v *VagrantCloud) CurrentNodeName(hostname string) (string, error) {
+	return hostname, nil
+}
+
 // NodeAddresses returns the NodeAddresses of a particular machine instance.
 func (v *VagrantCloud) NodeAddresses(instance string) ([]api.NodeAddress, error) {
 	// Due to vagrant not running with a dedicated DNS setup, we return the IP address of a minion as its hostname at this time
diff --git a/pkg/kubelet/kubelet.go b/pkg/kubelet/kubelet.go
index d1070cc390b..7a6b5c40983 100644
--- a/pkg/kubelet/kubelet.go
+++ b/pkg/kubelet/kubelet.go
@@ -1849,6 +1849,7 @@ func (kl *Kubelet) setNodeStatus(node *api.Node) error {
 		}
 		// TODO(roberthbailey): Can we do this without having credentials to talk
 		// to the cloud provider?
+		// TODO(justinsb): We can if CurrentNodeName() was actually CurrentNode() and returned an interface
 		nodeAddresses, err := instances.NodeAddresses(kl.nodeName)
 		if err != nil {
 			return fmt.Errorf("failed to get node address from cloud provider: %v", err)

From c89b0cd807526dfb690b3e16bb57d62809f0ffbe Mon Sep 17 00:00:00 2001
From: Justin Santa Barbara <justin@fathomdb.com>
Date: Thu, 11 Jun 2015 20:37:57 -0400
Subject: [PATCH 3/4] AWS: Use the instance id as the node name

The EC2 instance id is the canonical node name on EC2.
---
 pkg/cloudprovider/aws/aws.go      | 98 ++++++++++++-------------------
 pkg/cloudprovider/aws/aws_test.go | 28 ++++-----
 2 files changed, 52 insertions(+), 74 deletions(-)

diff --git a/pkg/cloudprovider/aws/aws.go b/pkg/cloudprovider/aws/aws.go
index c6a9d099ebf..67dad251cd4 100644
--- a/pkg/cloudprovider/aws/aws.go
+++ b/pkg/cloudprovider/aws/aws.go
@@ -235,7 +235,11 @@ func (self *AWSCloud) AddSSHKeyToAllInstances(user string, keyData []byte) error
 }
 
 func (a *AWSCloud) CurrentNodeName(hostname string) (string, error) {
-	return hostname, nil
+	selfInstance, err := a.getSelfAWSInstance()
+	if err != nil {
+		return "", err
+	}
+	return selfInstance.awsID, nil
 }
 
 // Implementation of EC2.Instances
@@ -551,7 +555,7 @@ func (aws *AWSCloud) Routes() (cloudprovider.Routes, bool) {
 
 // NodeAddresses is an implementation of Instances.NodeAddresses.
 func (aws *AWSCloud) NodeAddresses(name string) ([]api.NodeAddress, error) {
-	instance, err := aws.getInstanceByDnsName(name)
+	instance, err := aws.getInstanceById(name)
 	if err != nil {
 		return nil, err
 	}
@@ -585,7 +589,8 @@ func (aws *AWSCloud) NodeAddresses(name string) ([]api.NodeAddress, error) {
 
 // ExternalID returns the cloud provider ID of the specified instance (deprecated).
 func (aws *AWSCloud) ExternalID(name string) (string, error) {
-	inst, err := aws.getInstanceByDnsName(name)
+	// TODO: Do we need to verify it exists, or can we just return name
+	inst, err := aws.getInstanceById(name)
 	if err != nil {
 		return "", err
 	}
@@ -594,7 +599,8 @@ func (aws *AWSCloud) ExternalID(name string) (string, error) {
 
 // InstanceID returns the cloud provider ID of the specified instance.
 func (aws *AWSCloud) InstanceID(name string) (string, error) {
-	inst, err := aws.getInstanceByDnsName(name)
+	// TODO: Do we need to verify it exists, or can we just construct it knowing our AZ (or via caching?)
+	inst, err := aws.getInstanceById(name)
 	if err != nil {
 		return "", err
 	}
@@ -603,46 +609,6 @@ func (aws *AWSCloud) InstanceID(name string) (string, error) {
 	return "/" + orEmpty(inst.Placement.AvailabilityZone) + "/" + orEmpty(inst.InstanceID), nil
 }
 
-// Return the instances matching the relevant private dns name.
-func (s *AWSCloud) getInstanceByDnsName(name string) (*ec2.Instance, error) {
-	filters := []*ec2.Filter{
-		newEc2Filter("private-dns-name", name),
-	}
-	filters = s.addFilters(filters)
-	request := &ec2.DescribeInstancesInput{
-		Filters: filters,
-	}
-
-	instances, err := s.ec2.DescribeInstances(request)
-	if err != nil {
-		return nil, err
-	}
-
-	matchingInstances := []*ec2.Instance{}
-	for _, instance := range instances {
-		// TODO: Push running logic down into filter?
-		if !isAlive(instance) {
-			continue
-		}
-
-		if orEmpty(instance.PrivateDNSName) != name {
-			// TODO: Should we warn here? - the filter should have caught this
-			// (this will happen in the tests if they don't fully mock the EC2 API)
-			continue
-		}
-
-		matchingInstances = append(matchingInstances, instance)
-	}
-
-	if len(matchingInstances) == 0 {
-		return nil, fmt.Errorf("no instances found for host: %s", name)
-	}
-	if len(matchingInstances) > 1 {
-		return nil, fmt.Errorf("multiple instances found for host: %s", name)
-	}
-	return matchingInstances[0], nil
-}
-
 // Check if the instance is alive (running or pending)
 // We typically ignore instances that are not alive
 func isAlive(instance *ec2.Instance) bool {
@@ -702,16 +668,9 @@ func (s *AWSCloud) getInstancesByRegex(regex string) ([]string, error) {
 			continue
 		}
 
-		privateDNSName := orEmpty(instance.PrivateDNSName)
-		if privateDNSName == "" {
-			glog.V(2).Infof("skipping EC2 instance (no PrivateDNSName): %s",
-				orEmpty(instance.InstanceID))
-			continue
-		}
-
 		for _, tag := range instance.Tags {
 			if orEmpty(tag.Key) == "Name" && re.MatchString(orEmpty(tag.Value)) {
-				matchingInstances = append(matchingInstances, privateDNSName)
+				matchingInstances = append(matchingInstances, orEmpty(instance.InstanceID))
 				break
 			}
 		}
@@ -728,7 +687,7 @@ func (aws *AWSCloud) List(filter string) ([]string, error) {
 
 // GetNodeResources implements Instances.GetNodeResources
 func (aws *AWSCloud) GetNodeResources(name string) (*api.NodeResources, error) {
-	instance, err := aws.getInstanceByDnsName(name)
+	instance, err := aws.getInstanceById(name)
 	if err != nil {
 		return nil, err
 	}
@@ -1189,7 +1148,7 @@ func (aws *AWSCloud) getAwsInstance(instanceName string) (*awsInstance, error) {
 			return nil, fmt.Errorf("error getting self-instance: %v", err)
 		}
 	} else {
-		instance, err := aws.getInstanceByDnsName(instanceName)
+		instance, err := aws.getInstanceById(instanceName)
 		if err != nil {
 			return nil, fmt.Errorf("error finding instance: %v", err)
 		}
@@ -1656,7 +1615,7 @@ func (s *AWSCloud) CreateTCPLoadBalancer(name, region string, publicIP net.IP, p
 		return nil, fmt.Errorf("publicIP cannot be specified for AWS ELB")
 	}
 
-	instances, err := s.getInstancesByDnsNames(hosts)
+	instances, err := s.getInstancesByIds(hosts)
 	if err != nil {
 		return nil, err
 	}
@@ -2068,7 +2027,7 @@ func (s *AWSCloud) EnsureTCPLoadBalancerDeleted(name, region string) error {
 
 // UpdateTCPLoadBalancer implements TCPLoadBalancer.UpdateTCPLoadBalancer
 func (s *AWSCloud) UpdateTCPLoadBalancer(name, region string, hosts []string) error {
-	instances, err := s.getInstancesByDnsNames(hosts)
+	instances, err := s.getInstancesByIds(hosts)
 	if err != nil {
 		return err
 	}
@@ -2143,21 +2102,40 @@ func (s *AWSCloud) UpdateTCPLoadBalancer(name, region string, hosts []string) er
 }
 
 // TODO: Make efficient
-func (a *AWSCloud) getInstancesByDnsNames(names []string) ([]*ec2.Instance, error) {
+func (a *AWSCloud) getInstancesByIds(ids []string) ([]*ec2.Instance, error) {
 	instances := []*ec2.Instance{}
-	for _, name := range names {
-		instance, err := a.getInstanceByDnsName(name)
+	for _, id := range ids {
+		instance, err := a.getInstanceById(id)
 		if err != nil {
 			return nil, err
 		}
 		if instance == nil {
-			return nil, fmt.Errorf("unable to find instance " + name)
+			return nil, fmt.Errorf("unable to find instance " + id)
 		}
 		instances = append(instances, instance)
 	}
 	return instances, nil
 }
 
+// Returns the instance with the specified ID
+func (a *AWSCloud) getInstanceById(instanceID string) (*ec2.Instance, error) {
+	request := &ec2.DescribeInstancesInput{
+		InstanceIDs: []*string{&instanceID},
+	}
+
+	instances, err := a.ec2.DescribeInstances(request)
+	if err != nil {
+		return nil, err
+	}
+	if len(instances) == 0 {
+		return nil, fmt.Errorf("no instances found for instance: %s", instanceID)
+	}
+	if len(instances) > 1 {
+		return nil, fmt.Errorf("multiple instances found for instance: %s", instanceID)
+	}
+	return instances[0], nil
+}
+
 // Add additional filters, to match on our tags
 // This lets us run multiple k8s clusters in a single EC2 AZ
 func (s *AWSCloud) addFilters(filters []*ec2.Filter) []*ec2.Filter {
diff --git a/pkg/cloudprovider/aws/aws_test.go b/pkg/cloudprovider/aws/aws_test.go
index 469b8e352da..60462a74155 100644
--- a/pkg/cloudprovider/aws/aws_test.go
+++ b/pkg/cloudprovider/aws/aws_test.go
@@ -412,7 +412,7 @@ func TestList(t *testing.T) {
 		Value: aws.String("foo"),
 	}
 	instance0.Tags = []*ec2.Tag{&tag0}
-	instance0.PrivateDNSName = aws.String("instance1")
+	instance0.InstanceID = aws.String("instance0")
 	state0 := ec2.InstanceState{
 		Name: aws.String("running"),
 	}
@@ -424,7 +424,7 @@ func TestList(t *testing.T) {
 		Value: aws.String("bar"),
 	}
 	instance1.Tags = []*ec2.Tag{&tag1}
-	instance1.PrivateDNSName = aws.String("instance2")
+	instance1.InstanceID = aws.String("instance1")
 	state1 := ec2.InstanceState{
 		Name: aws.String("running"),
 	}
@@ -436,7 +436,7 @@ func TestList(t *testing.T) {
 		Value: aws.String("baz"),
 	}
 	instance2.Tags = []*ec2.Tag{&tag2}
-	instance2.PrivateDNSName = aws.String("instance3")
+	instance2.InstanceID = aws.String("instance2")
 	state2 := ec2.InstanceState{
 		Name: aws.String("running"),
 	}
@@ -448,7 +448,7 @@ func TestList(t *testing.T) {
 		Value: aws.String("quux"),
 	}
 	instance3.Tags = []*ec2.Tag{&tag3}
-	instance3.PrivateDNSName = aws.String("instance4")
+	instance3.InstanceID = aws.String("instance3")
 	state3 := ec2.InstanceState{
 		Name: aws.String("running"),
 	}
@@ -462,8 +462,8 @@ func TestList(t *testing.T) {
 		expect []string
 	}{
 		{"blahonga", []string{}},
-		{"quux", []string{"instance4"}},
-		{"a", []string{"instance2", "instance3"}},
+		{"quux", []string{"instance3"}},
+		{"a", []string{"instance1", "instance2"}},
 	}
 
 	for _, item := range table {
@@ -493,7 +493,7 @@ func TestNodeAddresses(t *testing.T) {
 	var instance1 ec2.Instance
 
 	//0
-	instance0.PrivateDNSName = aws.String("instance1")
+	instance0.InstanceID = aws.String("instance-same")
 	instance0.PrivateIPAddress = aws.String("192.168.0.1")
 	instance0.PublicIPAddress = aws.String("1.2.3.4")
 	instance0.InstanceType = aws.String("c3.large")
@@ -503,7 +503,7 @@ func TestNodeAddresses(t *testing.T) {
 	instance0.State = &state0
 
 	//1
-	instance1.PrivateDNSName = aws.String("instance1")
+	instance1.InstanceID = aws.String("instance-same")
 	instance1.PrivateIPAddress = aws.String("192.168.0.2")
 	instance1.InstanceType = aws.String("c3.large")
 	state1 := ec2.InstanceState{
@@ -514,19 +514,19 @@ func TestNodeAddresses(t *testing.T) {
 	instances := []*ec2.Instance{&instance0, &instance1}
 
 	aws1 := mockInstancesResp([]*ec2.Instance{})
-	_, err1 := aws1.NodeAddresses("instance")
+	_, err1 := aws1.NodeAddresses("instance-mismatch")
 	if err1 == nil {
 		t.Errorf("Should error when no instance found")
 	}
 
 	aws2 := mockInstancesResp(instances)
-	_, err2 := aws2.NodeAddresses("instance1")
+	_, err2 := aws2.NodeAddresses("instance-same")
 	if err2 == nil {
 		t.Errorf("Should error when multiple instances found")
 	}
 
 	aws3 := mockInstancesResp(instances[0:1])
-	addrs3, err3 := aws3.NodeAddresses("instance1")
+	addrs3, err3 := aws3.NodeAddresses("instance-same")
 	if err3 != nil {
 		t.Errorf("Should not error when instance found")
 	}
@@ -562,7 +562,7 @@ func TestGetResources(t *testing.T) {
 	var instance2 ec2.Instance
 
 	//0
-	instance0.PrivateDNSName = aws.String("m3.medium")
+	instance0.InstanceID = aws.String("m3.medium")
 	instance0.InstanceType = aws.String("m3.medium")
 	state0 := ec2.InstanceState{
 		Name: aws.String("running"),
@@ -570,7 +570,7 @@ func TestGetResources(t *testing.T) {
 	instance0.State = &state0
 
 	//1
-	instance1.PrivateDNSName = aws.String("r3.8xlarge")
+	instance1.InstanceID = aws.String("r3.8xlarge")
 	instance1.InstanceType = aws.String("r3.8xlarge")
 	state1 := ec2.InstanceState{
 		Name: aws.String("running"),
@@ -578,7 +578,7 @@ func TestGetResources(t *testing.T) {
 	instance1.State = &state1
 
 	//2
-	instance2.PrivateDNSName = aws.String("unknown.type")
+	instance2.InstanceID = aws.String("unknown.type")
 	instance2.InstanceType = aws.String("unknown.type")
 	state2 := ec2.InstanceState{
 		Name: aws.String("running"),

From 77e1bd3f56fea95a128bd3d9fe02fa78e9c6492c Mon Sep 17 00:00:00 2001
From: Justin Santa Barbara <justin@fathomdb.com>
Date: Tue, 16 Jun 2015 10:32:53 -0400
Subject: [PATCH 4/4] NodeName != HostName: Fixes for contrib/mesos

---
 contrib/mesos/pkg/executor/service/service.go | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/contrib/mesos/pkg/executor/service/service.go b/contrib/mesos/pkg/executor/service/service.go
index ad738fd8a24..dd3b6605b9e 100644
--- a/contrib/mesos/pkg/executor/service/service.go
+++ b/contrib/mesos/pkg/executor/service/service.go
@@ -259,6 +259,8 @@ func (s *KubeletExecutorServer) Run(hks hyperkube.Interface, _ []string) error {
 		DockerExecHandler:         dockerExecHandler,
 	}
 
+	kcfg.NodeName = kcfg.Hostname
+
 	err = app.RunKubelet(&kcfg, app.KubeletBuilder(func(kc *app.KubeletConfig) (app.KubeletBootstrap, *kconfig.PodConfig, error) {
 		return s.createAndInitKubelet(kc, hks, clientConfig, shutdownCloser)
 	}))
@@ -319,6 +321,7 @@ func (ks *KubeletExecutorServer) createAndInitKubelet(
 
 	klet, err := kubelet.NewMainKubelet(
 		kc.Hostname,
+		kc.NodeName,
 		kc.DockerClient,
 		kubeClient,
 		kc.RootDirectory,