kubernetes · machine424 · Oct 24, 2023 · dgrisonnet · Aug 28, 2024 · machine424
diff --git a/pkg/kubelet/kubelet.go b/pkg/kubelet/kubelet.go
@@ -1497,6 +1497,7 @@ func (kl *Kubelet) initializeModules() error {
 	metrics.Register(
 		collectors.NewVolumeStatsCollector(kl),
 		collectors.NewLogMetricsCollector(kl.StatsProvider.ListPodStats),
+		collectors.NewEmptyDirMetricsCollector(kl),
 	)
 	metrics.SetNodeName(kl.nodeName)
 	servermetrics.Register()

diff --git a/pkg/kubelet/metrics/collectors/emptydir_metrics.go b/pkg/kubelet/metrics/collectors/emptydir_metrics.go
@@ -0,0 +1,143 @@
+/*
+Copyright 2024 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package collectors
+
+import (
+	"context"
+
+	v1 "k8s.io/api/core/v1"
+	"k8s.io/component-base/metrics"
+	"k8s.io/klog/v2"
+
+	kubeletmetrics "k8s.io/kubernetes/pkg/kubelet/metrics"
+	serverstats "k8s.io/kubernetes/pkg/kubelet/server/stats"
+)
+
+var (
+	emptyDirUsedBytesDesc = metrics.NewDesc(
+		metrics.BuildFQName(
+			"",
+			kubeletmetrics.KubeletSubsystem,
+			kubeletmetrics.EmptyDirUsedBytesKey,
+		),
+		"Bytes used by the emptyDir volume. Only volumes on the default medium are considered.",
+		[]string{
+			"volume_name",
+			"namespace",
+			"pod",
+		},
+		nil,
+		metrics.ALPHA,
+		"",
+	)
+	emptyDirSizeLimitBytesDesc = metrics.NewDesc(
+		metrics.BuildFQName(
+			"",
+			kubeletmetrics.KubeletSubsystem,
+			kubeletmetrics.EmptyDirSizeLimitBytesKey,
+		),
+		"Size limit of the emptyDir volume in bytes, if set. Only volumes on the default medium are considered.",
+		[]string{
+			"volume_name",
+			"namespace",
+			"pod",
+		},
+		nil,
+		metrics.ALPHA,
+		"",
+	)
+)
+
+type emptyDirMetricsCollector struct {
+	metrics.BaseStableCollector
+
+	statsProvider serverstats.Provider
+}
+
+// Check if emptyDirMetricsCollector implements necessary interface
+var _ metrics.StableCollector = &emptyDirMetricsCollector{}
+
+// NewEmptyDirMetricsCollector implements the metrics.StableCollector interface and
+// exposes metrics about pod's emptyDir.
+func NewEmptyDirMetricsCollector(statsProvider serverstats.Provider) metrics.StableCollector {
+	return &emptyDirMetricsCollector{statsProvider: statsProvider}
+}
+
+// DescribeWithStability implements the metrics.StableCollector interface.
+func (c *emptyDirMetricsCollector) DescribeWithStability(ch chan<- *metrics.Desc) {
+	ch <- emptyDirUsedBytesDesc
+	ch <- emptyDirSizeLimitBytesDesc
+}
+
+// CollectWithStability implements the metrics.StableCollector interface.
+func (c *emptyDirMetricsCollector) CollectWithStability(ch chan<- metrics.Metric) {
+	podStats, err := c.statsProvider.ListPodStats(context.Background())
+	if err != nil {
+		klog.ErrorS(err, "Failed to get pod stats")
+		return
+	}
+
+	for _, podStat := range podStats {
+		podName := podStat.PodRef.Name
+		podNamespace := podStat.PodRef.Namespace
+
+		if podStat.VolumeStats == nil {
+			klog.V(5).InfoS("Pod has no volume stats", "pod", podName, "namespace", podNamespace)
+			continue
+		}
+
+		pod, found := c.statsProvider.GetPodByName(podNamespace, podName)
+		if !found {
+			klog.V(5).InfoS("Couldn't get pod", "pod", podName, "namespace", podNamespace)
+			continue
+		}
+
+		podVolumes := make(map[string]v1.Volume, len(pod.Spec.Volumes))
+		for _, volume := range pod.Spec.Volumes {
+			podVolumes[volume.Name] = volume
+		}
+
+		for _, volumeStat := range podStat.VolumeStats {
+			if volume, found := podVolumes[volumeStat.Name]; found {
+				// Only consider volumes on the default medium.
+				if volume.EmptyDir != nil && volume.EmptyDir.Medium == v1.StorageMediumDefault {
+					if volumeStat.UsedBytes != nil {
 if c.Logs != nil && c.Logs.UsedBytes != nil { 
 if c.Logs != nil && c.Logs.UsedBytes != nil { 
+						ch <- metrics.NewLazyConstMetric(
+							emptyDirUsedBytesDesc,
+							metrics.GaugeValue,
+							float64(*volumeStat.UsedBytes),
+							volumeStat.Name,
+							podNamespace,
+							podName,
+						)
+					}
+					if volume.EmptyDir.SizeLimit != nil {
+						ch <- metrics.NewLazyConstMetric(
+							emptyDirSizeLimitBytesDesc,
+							metrics.GaugeValue,
+							volume.EmptyDir.SizeLimit.AsApproximateFloat64(),
+							volumeStat.Name,
+							podNamespace,
+							podName,
+						)
+					}
+				}
+			}
+
+		}
+	}
+}
diff --git a/pkg/kubelet/metrics/collectors/emptydir_metrics_test.go b/pkg/kubelet/metrics/collectors/emptydir_metrics_test.go
@@ -0,0 +1,158 @@
+/*
+Copyright 2024 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package collectors
+
+import (
+	"context"
+	"strings"
+	"testing"
+
+	"k8s.io/apimachinery/pkg/api/resource"
+
+	v1 "k8s.io/api/core/v1"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/component-base/metrics/testutil"
+	statsapi "k8s.io/kubelet/pkg/apis/stats/v1alpha1"
+	statstest "k8s.io/kubernetes/pkg/kubelet/server/stats/testing"
+)
+
+func TestEmptyDirCollector(t *testing.T) {
+
+	testNamespace := "test-namespace"
+	existingPodNameWithStats := "foo"
+	podNameWithoutStats := "bar"
+
+	podStats := []statsapi.PodStats{
+		{
+			PodRef: statsapi.PodReference{
+				Name:      existingPodNameWithStats,
+				Namespace: testNamespace,
+				UID:       "UID_foo",
+			},
+			StartTime: metav1.Now(),
+			VolumeStats: []statsapi.VolumeStats{
+				{
+					Name: "foo-emptydir-1",
+					FsStats: statsapi.FsStats{
+						UsedBytes: newUint64Pointer(2101248),
+					},
+				},
+				{
+					Name: "foo-emptydir-2",
+					FsStats: statsapi.FsStats{
+						UsedBytes: newUint64Pointer(6488064),
+					},
+				},
+				{
+					Name: "foo-memory-emptydir",
+					FsStats: statsapi.FsStats{
+						UsedBytes: newUint64Pointer(25362432),
+					},
+				},
+				{
+					Name: "foo-configmap",
+					FsStats: statsapi.FsStats{
+						UsedBytes: newUint64Pointer(4096),
+					},
+				},
+			},
+		},
+	}
+
+	existingPod := &v1.Pod{
+		ObjectMeta: metav1.ObjectMeta{
+			Name:      existingPodNameWithStats,
+			Namespace: testNamespace,
+		},
+		Spec: v1.PodSpec{
+			Volumes: []v1.Volume{
+				{
+					Name: "foo-emptydir-1",
+					VolumeSource: v1.VolumeSource{
+						EmptyDir: &v1.EmptyDirVolumeSource{SizeLimit: resource.NewQuantity(3000100, resource.BinarySI)},
+					},
+				},
+				{
+					Name: "foo-emptydir-2",
+					VolumeSource: v1.VolumeSource{
+						EmptyDir: &v1.EmptyDirVolumeSource{},
+					},
+				},
+				{
+					Name: "foo-memory-emptydir",
+					VolumeSource: v1.VolumeSource{
+						EmptyDir: &v1.EmptyDirVolumeSource{Medium: v1.StorageMediumMemory},
+					},
+				},
+				{
+					Name: "foo-configmap",
+					VolumeSource: v1.VolumeSource{
+						ConfigMap: &v1.ConfigMapVolumeSource{},
+					},
+				},
+			},
+		},
+	}
+
+	podWithoutStats := &v1.Pod{
+		ObjectMeta: metav1.ObjectMeta{
+			Name:      podNameWithoutStats,
+			Namespace: testNamespace,
+		},
+		Spec: v1.PodSpec{
+			Volumes: []v1.Volume{
+				{
+					Name: "bar-emptydir",
+					VolumeSource: v1.VolumeSource{
+						EmptyDir: &v1.EmptyDirVolumeSource{},
+					},
+				},
+			},
+		},
+	}
+
+	mockStatsProvider := statstest.NewMockProvider(t)
+
+	mockStatsProvider.EXPECT().ListPodStats(context.Background()).Return(podStats, nil).Maybe()
+	mockStatsProvider.EXPECT().
+		GetPodByName(testNamespace, existingPodNameWithStats).
+		Return(existingPod, true).
+		Maybe()
+	mockStatsProvider.EXPECT().
+		GetPodByName(testNamespace, podNameWithoutStats).
+		Return(podWithoutStats, true).
+		Maybe()
+
+	err := testutil.CustomCollectAndCompare(
+		&emptyDirMetricsCollector{statsProvider: mockStatsProvider},
+		strings.NewReader(`
+		# HELP kubelet_pod_emptydir_volume_size_limit_bytes [ALPHA] Size limit of the emptyDir volume in bytes, if set. Only volumes on the default medium are considered.
+		# TYPE kubelet_pod_emptydir_volume_size_limit_bytes gauge
+		kubelet_pod_emptydir_volume_size_limit_bytes{namespace="test-namespace",pod="foo",volume_name="foo-emptydir-1"} 3.0001e+06
+		# HELP kubelet_pod_emptydir_volume_used_bytes [ALPHA] Bytes used by the emptyDir volume. Only volumes on the default medium are considered.
+		# TYPE kubelet_pod_emptydir_volume_used_bytes gauge
+		kubelet_pod_emptydir_volume_used_bytes{namespace="test-namespace",pod="foo",volume_name="foo-emptydir-1"} 2.101248e+06
+		kubelet_pod_emptydir_volume_used_bytes{namespace="test-namespace",pod="foo",volume_name="foo-emptydir-2"} 6.488064e+06
+		`),
+		"kubelet_pod_emptydir_volume_size_limit_bytes",
+		"kubelet_pod_emptydir_volume_used_bytes",
+	)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+}
diff --git a/pkg/kubelet/metrics/metrics.go b/pkg/kubelet/metrics/metrics.go
@@ -58,6 +58,8 @@ const (
 	PreemptionsKey                     = "preemptions"
 	VolumeStatsCapacityBytesKey        = "volume_stats_capacity_bytes"
 	VolumeStatsAvailableBytesKey       = "volume_stats_available_bytes"
+	EmptyDirUsedBytesKey               = "pod_emptydir_volume_used_bytes"
+	EmptyDirSizeLimitBytesKey          = "pod_emptydir_volume_size_limit_bytes"
 	VolumeStatsUsedBytesKey            = "volume_stats_used_bytes"
 	VolumeStatsInodesKey               = "volume_stats_inodes"
 	VolumeStatsInodesFreeKey           = "volume_stats_inodes_free"