Merge pull request #51553 from wongma7/pvc-prometheus

Automatic merge from submit-queue

Expose PVC metrics via kubelet prometheus

This depends on https://github.com/kubernetes/kubernetes/pull/51448, opening early though. second commit is mine and mostly a copy/paste job.

implements metrics listed in here https://github.com/kubernetes/community/pull/855 following method here https://github.com/kubernetes/community/pull/930#issuecomment-325509736

**Which issue this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close that issue when PR gets merged)*: https://github.com/kubernetes/features/issues/363

**Special notes for your reviewer**:

**Release note**:

```release-note
PersistentVolumeClaim metrics like "volume_stats_inodes" and "volume_stats_capacity_bytes" are now reported via kubelet prometheus
```

pkg/kubelet/metrics/metrics.go

@@ -26,18 +26,24 @@ import (
 )
 
 const (
-	KubeletSubsystem           = "kubelet"
-	PodWorkerLatencyKey        = "pod_worker_latency_microseconds"
-	PodStartLatencyKey         = "pod_start_latency_microseconds"
-	CgroupManagerOperationsKey = "cgroup_manager_latency_microseconds"
-	DockerOperationsLatencyKey = "docker_operations_latency_microseconds"
-	DockerOperationsKey        = "docker_operations"
-	DockerOperationsErrorsKey  = "docker_operations_errors"
-	DockerOperationsTimeoutKey = "docker_operations_timeout"
-	PodWorkerStartLatencyKey   = "pod_worker_start_latency_microseconds"
-	PLEGRelistLatencyKey       = "pleg_relist_latency_microseconds"
-	PLEGRelistIntervalKey      = "pleg_relist_interval_microseconds"
-	EvictionStatsAgeKey        = "eviction_stats_age_microseconds"
+	KubeletSubsystem             = "kubelet"
+	PodWorkerLatencyKey          = "pod_worker_latency_microseconds"
+	PodStartLatencyKey           = "pod_start_latency_microseconds"
+	CgroupManagerOperationsKey   = "cgroup_manager_latency_microseconds"
+	DockerOperationsLatencyKey   = "docker_operations_latency_microseconds"
+	DockerOperationsKey          = "docker_operations"
+	DockerOperationsErrorsKey    = "docker_operations_errors"
+	DockerOperationsTimeoutKey   = "docker_operations_timeout"
+	PodWorkerStartLatencyKey     = "pod_worker_start_latency_microseconds"
+	PLEGRelistLatencyKey         = "pleg_relist_latency_microseconds"
+	PLEGRelistIntervalKey        = "pleg_relist_interval_microseconds"
+	EvictionStatsAgeKey          = "eviction_stats_age_microseconds"
+	VolumeStatsCapacityBytesKey  = "volume_stats_capacity_bytes"
+	VolumeStatsAvailableBytesKey = "volume_stats_available_bytes"
+	VolumeStatsUsedBytesKey      = "volume_stats_used_bytes"
+	VolumeStatsInodesKey         = "volume_stats_inodes"
+	VolumeStatsInodesFreeKey     = "volume_stats_inodes_free"
+	VolumeStatsInodesUsedKey     = "volume_stats_inodes_used"
 	// Metrics keys of remote runtime operations
 	RuntimeOperationsKey        = "runtime_operations"
 	RuntimeOperationsLatencyKey = "runtime_operations_latency_microseconds"
@@ -162,6 +168,54 @@ var (
 		},
 		[]string{"eviction_signal"},
 	)
+	VolumeStatsCapacityBytes = prometheus.NewGaugeVec(
+		prometheus.GaugeOpts{
+			Subsystem: KubeletSubsystem,
+			Name:      VolumeStatsCapacityBytesKey,
+			Help:      "Capacity in bytes of the volume",
+		},
+		[]string{"namespace", "persistentvolumeclaim"},
+	)
+	VolumeStatsAvailableBytes = prometheus.NewGaugeVec(
+		prometheus.GaugeOpts{
+			Subsystem: KubeletSubsystem,
+			Name:      VolumeStatsAvailableBytesKey,
+			Help:      "Number of available bytes in the volume",
+		},
+		[]string{"namespace", "persistentvolumeclaim"},
+	)
+	VolumeStatsUsedBytes = prometheus.NewGaugeVec(
+		prometheus.GaugeOpts{
+			Subsystem: KubeletSubsystem,
+			Name:      VolumeStatsUsedBytesKey,
+			Help:      "Number of used bytes in the volume",
+		},
+		[]string{"namespace", "persistentvolumeclaim"},
+	)
+	VolumeStatsInodes = prometheus.NewGaugeVec(
+		prometheus.GaugeOpts{
+			Subsystem: KubeletSubsystem,
+			Name:      VolumeStatsInodesKey,
+			Help:      "Maximum number of inodes in the volume",
+		},
+		[]string{"namespace", "persistentvolumeclaim"},
+	)
+	VolumeStatsInodesFree = prometheus.NewGaugeVec(
+		prometheus.GaugeOpts{
+			Subsystem: KubeletSubsystem,
+			Name:      VolumeStatsInodesFreeKey,
+			Help:      "Number of free inodes in the volume",
+		},
+		[]string{"namespace", "persistentvolumeclaim"},
+	)
+	VolumeStatsInodesUsed = prometheus.NewGaugeVec(
+		prometheus.GaugeOpts{
+			Subsystem: KubeletSubsystem,
+			Name:      VolumeStatsInodesUsedKey,
+			Help:      "Number of used inodes in the volume",
+		},
+		[]string{"namespace", "persistentvolumeclaim"},
+	)
 )
 
 var registerMetrics sync.Once
@@ -186,6 +240,12 @@ func Register(containerCache kubecontainer.RuntimeCache) {
 		prometheus.MustRegister(RuntimeOperationsLatency)
 		prometheus.MustRegister(RuntimeOperationsErrors)
 		prometheus.MustRegister(EvictionStatsAge)
+		prometheus.MustRegister(VolumeStatsCapacityBytes)
+		prometheus.MustRegister(VolumeStatsAvailableBytes)
+		prometheus.MustRegister(VolumeStatsUsedBytes)
+		prometheus.MustRegister(VolumeStatsInodes)
+		prometheus.MustRegister(VolumeStatsInodesFree)
+		prometheus.MustRegister(VolumeStatsInodesUsed)
 	})
 }
 

pkg/kubelet/server/stats/BUILD

@@ -15,6 +15,7 @@ go_library(
         "//pkg/kubelet/apis/stats/v1alpha1:go_default_library",
         "//pkg/kubelet/cm:go_default_library",
         "//pkg/kubelet/container:go_default_library",
+        "//pkg/kubelet/metrics:go_default_library",
         "//pkg/kubelet/util/format:go_default_library",
         "//pkg/volume:go_default_library",
         "//vendor/github.com/emicklei/go-restful:go_default_library",

pkg/kubelet/server/stats/volume_stat_calculator.go

@@ -24,6 +24,7 @@ import (
 	"k8s.io/api/core/v1"
 	"k8s.io/apimachinery/pkg/util/wait"
 	stats "k8s.io/kubernetes/pkg/kubelet/apis/stats/v1alpha1"
+	"k8s.io/kubernetes/pkg/kubelet/metrics"
 	"k8s.io/kubernetes/pkg/kubelet/util/format"
 	"k8s.io/kubernetes/pkg/volume"
 
@@ -85,6 +86,7 @@ func (s *volumeStatCalculator) GetLatest() (PodVolumeStats, bool) {
 }
 
 // calcAndStoreStats calculates PodVolumeStats for a given pod and writes the result to the s.latest cache.
+// If the pod references PVCs, the prometheus metrics for those are updated with the result.
 func (s *volumeStatCalculator) calcAndStoreStats() {
 	// Find all Volumes for the Pod
 	volumes, found := s.statsProvider.ListVolumesForPod(s.pod.UID)
@@ -117,6 +119,8 @@ func (s *volumeStatCalculator) calcAndStoreStats() {
 				Namespace: s.pod.GetNamespace(),
 			}
 			fsStats = append(fsStats, s.parsePodVolumeStats(name, &pvcRef, metric))
+			// Set the PVC's prometheus metrics
+			s.setPVCMetrics(&pvcRef, metric)
 		} else {
 			fsStats = append(fsStats, s.parsePodVolumeStats(name, nil, metric))
 		}
@@ -141,3 +145,13 @@ func (s *volumeStatCalculator) parsePodVolumeStats(podName string, pvcRef *stats
 			UsedBytes: &used, Inodes: &inodes, InodesFree: &inodesFree, InodesUsed: &inodesUsed},
 	}
 }
+
+// setPVCMetrics sets the given PVC's prometheus metrics to match the given volume.Metrics
+func (s *volumeStatCalculator) setPVCMetrics(pvcRef *stats.PVCReference, metric *volume.Metrics) {
+	metrics.VolumeStatsAvailableBytes.WithLabelValues(pvcRef.Namespace, pvcRef.Name).Set(float64(metric.Available.Value()))
+	metrics.VolumeStatsCapacityBytes.WithLabelValues(pvcRef.Namespace, pvcRef.Name).Set(float64(metric.Capacity.Value()))
+	metrics.VolumeStatsUsedBytes.WithLabelValues(pvcRef.Namespace, pvcRef.Name).Set(float64(metric.Used.Value()))
+	metrics.VolumeStatsInodes.WithLabelValues(pvcRef.Namespace, pvcRef.Name).Set(float64(metric.Inodes.Value()))
+	metrics.VolumeStatsInodesFree.WithLabelValues(pvcRef.Namespace, pvcRef.Name).Set(float64(metric.InodesFree.Value()))
+	metrics.VolumeStatsInodesUsed.WithLabelValues(pvcRef.Namespace, pvcRef.Name).Set(float64(metric.InodesUsed.Value()))
+}