Kubernetes SD: Add node name and host IP to pod discovery

retrieval/discovery/kubernetes/discovery.go

@@ -62,6 +62,10 @@ const (
 	podLabelPrefix = metaLabelPrefix + "pod_label_"
 	// podAnnotationPrefix is the prefix for prom label names corresponding to k8s annotations for a target pod
 	podAnnotationPrefix = metaLabelPrefix + "pod_annotation_"
+	// podNodeLabel is the name for the label containing the name of the node that a pod is scheduled on to
+	podNodeNameLabel = metaLabelPrefix + "pod_node_name"
+	// podHostIPLabel is the name for the label containing the IP of the node that a pod is scheduled on to
+	podHostIPLabel = metaLabelPrefix + "pod_host_ip"
 
 	sourceServicePrefix = "services"
 	// serviceNamespaceLabel is the name for the label containing a target's service namespace.

retrieval/discovery/kubernetes/discovery_test.go

@@ -117,9 +117,11 @@ func pod(name string, containers []Container) *Pod {
 					Status: "True",
 				},
 			},
+			HostIP: "2.2.2.2",
 		},
 		PodSpec: PodSpec{
 			Containers: c,
+			NodeName:   "test-node",
 		},
 	}
 }
@@ -147,6 +149,12 @@ func TestUpdatePodTargets(t *testing.T) {
 			t.Fatalf("expected 0 targets, received %d", len(result))
 		}
 
+		// Return no targets for a pod that has no HostIP
+		result = updatePodTargets(&Pod{PodStatus: PodStatus{PodIP: "1.1.1.1", Phase: "Running"}}, true)
+		if len(result) > 0 {
+			t.Fatalf("expected 0 targets, received %d", len(result))
+		}
+
 		// A pod with all valid containers should return one target per container with allContainers=true
 		result = updatePodTargets(pod("easy", []Container{container("a", portsA), container("b", portsB)}), true)
 		if len(result) != 2 {
@@ -167,6 +175,12 @@ func TestUpdatePodTargets(t *testing.T) {
 		if result[1][podContainerPortMapPrefix+"https"] != "443" {
 			t.Fatalf("expected result[1][podContainerPortMapPrefix + 'https'] to be '443', but was %s", result[1][podContainerPortMapPrefix+"https"])
 		}
+		if result[0][podNodeNameLabel] != "test-node" {
+			t.Fatalf("expected result[0] podNodeNameLabel 'test-node', received '%s'", result[0][podNodeNameLabel])
+		}
+		if result[0][podHostIPLabel] != "2.2.2.2" {
+			t.Fatalf("expected result[0] podHostIPLabel '2.2.2.2', received '%s'", result[0][podHostIPLabel])
+		}
 
 		// A pod with all valid containers should return one target with allContainers=false, and it should be the alphabetically first container
 		result = updatePodTargets(pod("easy", []Container{container("a", portsA), container("b", portsB)}), false)

retrieval/discovery/kubernetes/pod.go

@@ -255,6 +255,12 @@ func updatePodTargets(pod *Pod, allContainers bool) []model.LabelSet {
 		return targets
 	}
 
+	// Should never hit this (running pods should always have this set), but better to be defensive.
+	if pod.PodStatus.HostIP == "" {
+		log.Debugf("skipping pod %s -- PodStatus.HostIP is empty", pod.ObjectMeta.Name)
+		return targets
+	}
+
 	ready := "unknown"
 	for _, cond := range pod.PodStatus.Conditions {
 		if strings.ToLower(cond.Type) == "ready" {
@@ -293,6 +299,8 @@ func updatePodTargets(pod *Pod, allContainers bool) []model.LabelSet {
 			podContainerNameLabel:     model.LabelValue(container.Name),
 			podContainerPortNameLabel: model.LabelValue(tcpPorts[0].Name),
 			podReadyLabel:             model.LabelValue(ready),
+			podNodeNameLabel:          model.LabelValue(pod.PodSpec.NodeName),
+			podHostIPLabel:            model.LabelValue(pod.PodStatus.HostIP),
 		}
 
 		for _, port := range tcpPorts {

retrieval/discovery/kubernetes/types.go

@@ -285,10 +285,12 @@ type PodStatus struct {
 	Phase      string         `json:"phase" description:"Current condition of the pod. More info: http://kubernetes.io/v1.1/docs/user-guide/pod-states.html#pod-phase"`
 	PodIP      string         `json:"podIP" description:"IP address allocated to the pod. Routable at least within the cluster. Empty if not yet allocated."`
 	Conditions []PodCondition `json:"conditions" description:"Current service state of pod."`
+	HostIP     string         `json:"hostIP,omitempty" description:"IP address of the host to which the pod is assigned. Empty if not yet scheduled."`
 }
 
 type PodSpec struct {
 	Containers []Container `json:"containers" description:"list of containers, see http://kubernetes.io/v1.1/docs/api-reference/v1/definitions.html#_v1_container"`
+	NodeName   string      `json:"nodeName,omitempty" description:"NodeName is a request to schedule this pod onto a specific node. If it is non-empty, the scheduler simply schedules this pod onto that node, assuming that it fits resource requirements."`
 }
 
 type PodCondition struct {