Add metric deleting_pods_total

pkg/controller/podgc/gc_controller.go

@@ -76,6 +76,9 @@ func NewPodGC(ctx context.Context, kubeClient clientset.Interface, podInformer c
 // This function is only intended for integration tests
 func NewPodGCInternal(ctx context.Context, kubeClient clientset.Interface, podInformer coreinformers.PodInformer,
 	nodeInformer coreinformers.NodeInformer, terminatedPodThreshold int, gcCheckPeriod, quarantineTime time.Duration) *PodGCController {
+	// Register prometheus metrics
+	Register()
+
 	gcc := &PodGCController{
 		kubeClient:             kubeClient,
 		terminatedPodThreshold: terminatedPodThreshold,
@@ -173,9 +176,11 @@ func (gcc *PodGCController) gcTerminating(ctx context.Context, pods []*v1.Pod) {
 		wait.Add(1)
 		go func(pod *v1.Pod) {
 			defer wait.Done()
+			deletingPodsTotal.WithLabelValues().Inc()
 			if err := gcc.markFailedAndDeletePod(ctx, pod); err != nil {
 				// ignore not founds
 				utilruntime.HandleError(err)
+				deletingPodsErrorTotal.WithLabelValues().Inc()
 			}
 		}(terminatingPods[i])
 	}

pkg/controller/podgc/gc_controller_test.go

@@ -35,6 +35,7 @@ import (
 	clienttesting "k8s.io/client-go/testing"
 	"k8s.io/client-go/util/workqueue"
 	featuregatetesting "k8s.io/component-base/featuregate/testing"
+	metricstestutil "k8s.io/component-base/metrics/testutil"
 	"k8s.io/kubernetes/pkg/controller"
 	"k8s.io/kubernetes/pkg/controller/testutil"
 	"k8s.io/kubernetes/pkg/features"
@@ -631,6 +632,8 @@ func TestGCTerminating(t *testing.T) {
 			verifyDeletedAndPatchedPods(t, client, test.deletedPodNames, test.patchedPodNames)
 		})
 	}
+	// deletingPodsTotal is 7 in this test
+	testDeletingPodsMetrics(t, 7)
 }
 
 func verifyDeletedAndPatchedPods(t *testing.T, client *fake.Clientset, wantDeletedPodNames, wantPatchedPodNames sets.String) {
@@ -645,6 +648,26 @@ func verifyDeletedAndPatchedPods(t *testing.T, client *fake.Clientset, wantDelet
 	}
 }
 
+func testDeletingPodsMetrics(t *testing.T, inputDeletingPodsTotal int) {
+	t.Helper()
+
+	actualDeletingPodsTotal, err := metricstestutil.GetCounterMetricValue(deletingPodsTotal.WithLabelValues())
+	if err != nil {
+		t.Errorf("Error getting actualDeletingPodsTotal")
+	}
+	if actualDeletingPodsTotal != float64(inputDeletingPodsTotal) {
+		t.Errorf("Expected desiredDeletingPodsTotal to be %d, got %v", inputDeletingPodsTotal, actualDeletingPodsTotal)
+	}
+
+	actualDeletingPodsErrorTotal, err := metricstestutil.GetCounterMetricValue(deletingPodsErrorTotal.WithLabelValues())
+	if err != nil {
+		t.Errorf("Error getting actualDeletingPodsErrorTotal")
+	}
+	if actualDeletingPodsErrorTotal != float64(0) {
+		t.Errorf("Expected desiredDeletingPodsTotal to be %d, got %v", 0, actualDeletingPodsErrorTotal)
+	}
+}
+
 func setupNewSimpleClient(nodes []*v1.Node, pods []*v1.Pod) *fake.Clientset {
 	podList := &v1.PodList{}
 	for _, podItem := range pods {

pkg/controller/podgc/metrics.go

@@ -0,0 +1,61 @@
+/*
+Copyright 2022 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 podgc
+
+import (
+	"sync"
+
+	"k8s.io/component-base/metrics"
+	"k8s.io/component-base/metrics/legacyregistry"
+)
+
+const (
+	podGCController   = "pod_gc_collector"
+	deletingPods      = "deleting_pods_total"
+	deletingPodsError = "deleting_pods_error_total"
+)
+
+var (
+	deletingPodsTotal = metrics.NewCounterVec(
+		&metrics.CounterOpts{
+			Subsystem:      podGCController,
+			Name:           deletingPods,
+			Help:           "Number of pods that are being forcefully deleted since the Pod GC Controller started.",
+			StabilityLevel: metrics.ALPHA,
+		},
+		[]string{},
+	)
+	deletingPodsErrorTotal = metrics.NewCounterVec(
+		&metrics.CounterOpts{
+			Subsystem:      podGCController,
+			Name:           deletingPodsError,
+			Help:           "Number of errors encountered when forcefully deleting the pods since the Pod GC Controller started.",
+			StabilityLevel: metrics.ALPHA,
+		},
+		[]string{},
+	)
+)
+
+var registerMetrics sync.Once
+
+// Register the metrics that are to be monitored.
+func Register() {
+	registerMetrics.Do(func() {
+		legacyregistry.MustRegister(deletingPodsTotal)
+		legacyregistry.MustRegister(deletingPodsErrorTotal)
+	})
+}