DO NOT MERGE: Add per pod/namespace eviction counter to assess impact

pkg/registry/core/pod/storage/eviction.go

@@ -58,6 +58,7 @@ var EvictionsRetry = wait.Backoff{
 }
 
 func newEvictionStorage(store rest.StandardStorage, podDisruptionBudgetClient policyclient.PodDisruptionBudgetsGetter) *EvictionREST {
+	registerMetrics()
 	return &EvictionREST{store: store, podDisruptionBudgetClient: podDisruptionBudgetClient}
 }
 
@@ -161,6 +162,9 @@ func (r *EvictionREST) Create(ctx context.Context, name string, obj runtime.Obje
 		if err != nil {
 			return err
 		}
+		if pod.DeletionTimestamp == nil {
+			evictionsTotal.Inc()
+		}
 		deletedPod = true
 		return nil
 	})
@@ -267,6 +271,9 @@ func (r *EvictionREST) Create(ctx context.Context, name string, obj runtime.Obje
 		return nil, err
 	}
 
+	evictionsTotal.Inc()
+	//evictionsTotal.WithLabelValues(pod.Namespace, pod.Name).Inc()
+
 	// Success!
 	return &metav1.Status{Status: metav1.StatusSuccess}, nil
 }

pkg/registry/core/pod/storage/metrics.go

@@ -0,0 +1,32 @@
+package storage
+
+import (
+	"sync"
+
+	"k8s.io/component-base/metrics"
+	"k8s.io/component-base/metrics/legacyregistry"
+)
+
+const metricsSubsystem = "kube_apiserver"
+
+var (
+	// EvictionsTotal is the number of successful evictions performed.
+	// This metric is incremented exactly one time per pod.
+	evictionsTotal = metrics.NewGauge(
+		&metrics.GaugeOpts{
+			Subsystem:      metricsSubsystem,
+			Name:           "evictions_total",
+			Help:           "The number of successful evictions performed for each pod. This is incremented exactly once when a pod is marked deleted.",
+			StabilityLevel: metrics.ALPHA,
+		},
+	)
+)
+
+var registerMetricsOnce sync.Once
+
+// registerMetrics registers storage metrics.
+func registerMetrics() {
+	registerMetricsOnce.Do(func() {
+		legacyregistry.MustRegister(evictionsTotal)
+	})
+}