Add kubelet_node_name metrics

pkg/kubelet/kubelet.go

@@ -1303,6 +1303,7 @@ func (kl *Kubelet) initializeModules() error {
 		collectors.NewVolumeStatsCollector(kl),
 		collectors.NewLogMetricsCollector(kl.StatsProvider.ListPodStats),
 	)
+	metrics.SetNodeName(kl.nodeName)
 
 	// Setup filesystem directories.
 	if err := kl.setupDataDirs(); err != nil {

pkg/kubelet/metrics/BUILD

@@ -13,6 +13,7 @@ go_library(
         "//pkg/features:go_default_library",
         "//pkg/kubelet/container:go_default_library",
         "//staging/src/k8s.io/api/core/v1:go_default_library",
+        "//staging/src/k8s.io/apimachinery/pkg/types:go_default_library",
         "//staging/src/k8s.io/apiserver/pkg/util/feature:go_default_library",
         "//vendor/github.com/prometheus/client_golang/prometheus:go_default_library",
         "//vendor/k8s.io/klog:go_default_library",

pkg/kubelet/metrics/metrics.go

@@ -23,6 +23,7 @@ import (
 
 	"github.com/prometheus/client_golang/prometheus"
 	corev1 "k8s.io/api/core/v1"
+	"k8s.io/apimachinery/pkg/types"
 	utilfeature "k8s.io/apiserver/pkg/util/feature"
 	"k8s.io/klog"
 	"k8s.io/kubernetes/pkg/features"
@@ -31,6 +32,8 @@ import (
 
 const (
 	KubeletSubsystem             = "kubelet"
+	NodeNameKey                  = "node_name"
+	NodeLabelKey                 = "node"
 	PodWorkerLatencyKey          = "pod_worker_latency_microseconds"
 	PodStartLatencyKey           = "pod_start_latency_microseconds"
 	CgroupManagerOperationsKey   = "cgroup_manager_latency_microseconds"
@@ -65,6 +68,14 @@ const (
 )
 
 var (
+	NodeName = prometheus.NewGaugeVec(
+		prometheus.GaugeOpts{
+			Subsystem: KubeletSubsystem,
+			Name:      NodeNameKey,
+			Help:      "The node's name. The count is always 1.",
+		},
+		[]string{NodeLabelKey},
+	)
 	ContainersPerPodCount = prometheus.NewSummary(
 		prometheus.SummaryOpts{
 			Subsystem: KubeletSubsystem,
@@ -207,6 +218,7 @@ var registerMetrics sync.Once
 func Register(containerCache kubecontainer.RuntimeCache, collectors ...prometheus.Collector) {
 	// Register the metrics.
 	registerMetrics.Do(func() {
+		prometheus.MustRegister(NodeName)
 		prometheus.MustRegister(PodWorkerLatency)
 		prometheus.MustRegister(PodStartLatency)
 		prometheus.MustRegister(CgroupManagerLatency)
@@ -372,3 +384,7 @@ func SetConfigError(err bool) {
 		ConfigError.Set(0)
 	}
 }
+
+func SetNodeName(name types.NodeName) {
+	NodeName.WithLabelValues(string(name)).Set(1)
+}