add 25s bucket

staging/src/k8s.io/apiserver/pkg/admission/metrics/metrics.go

@@ -178,7 +178,7 @@ func newAdmissionMetrics() *AdmissionMetrics {
 				Subsystem:      subsystem,
 				Name:           "webhook_admission_duration_seconds",
 				Help:           "Admission webhook latency histogram in seconds, identified by name and broken out for each operation and API resource and type (validate or admit).",
-				Buckets:        []float64{0.005, 0.025, 0.1, 0.5, 1.0, 2.5, 10},
+				Buckets:        []float64{0.005, 0.025, 0.1, 0.5, 1.0, 2.5, 10, 25},
 				StabilityLevel: metrics.STABLE,
 			},
 			[]string{"name", "type", "operation", "rejected"},

test/instrumentation/testdata/stable-metrics-list.yaml

@@ -291,6 +291,7 @@
   - 1
   - 2.5
   - 10
+  - 25
 - name: current_inflight_requests
   subsystem: apiserver
   help: Maximal number of currently used inflight request limit of this apiserver