enable health check SLI metrics for apiserver

Change-Id: I1b43e6dfea35b8c3bfdf5daaa8b42adff2fbc786

staging/src/k8s.io/apiserver/pkg/server/config.go

@@ -67,6 +67,7 @@ import (
 	"k8s.io/client-go/informers"
 	restclient "k8s.io/client-go/rest"
 	"k8s.io/component-base/logs"
+	"k8s.io/component-base/metrics/prometheus/slis"
 	"k8s.io/klog/v2"
 	openapicommon "k8s.io/kube-openapi/pkg/common"
 	"k8s.io/kube-openapi/pkg/validation/spec"
@@ -884,8 +885,10 @@ func installAPI(s *GenericAPIServer, c *Config) {
 	if c.EnableMetrics {
 		if c.EnableProfiling {
 			routes.MetricsWithReset{}.Install(s.Handler.NonGoRestfulMux)
+			slis.SLIMetricsWithReset{}.Install(s.Handler.NonGoRestfulMux)
 		} else {
 			routes.DefaultMetrics{}.Install(s.Handler.NonGoRestfulMux)
+			slis.SLIMetrics{}.Install(s.Handler.NonGoRestfulMux)
 		}
 	}
 

staging/src/k8s.io/apiserver/pkg/server/config_test.go

@@ -169,6 +169,7 @@ func TestNewWithDelegate(t *testing.T) {
 		"/livez/poststarthook/storage-object-count-tracker-hook",
 		"/livez/poststarthook/wrapping-post-start-hook",
 		"/metrics",
+		"/metrics/slis",
 		"/readyz",
 		"/readyz/delegate-health",
 		"/readyz/informer-sync",

staging/src/k8s.io/apiserver/pkg/server/healthz/healthz.go

@@ -18,6 +18,7 @@ package healthz
 
 import (
 	"bytes"
+	"context"
 	"fmt"
 	"net/http"
 	"reflect"
@@ -30,6 +31,7 @@ import (
 	"k8s.io/apimachinery/pkg/util/wait"
 	"k8s.io/apiserver/pkg/endpoints/metrics"
 	"k8s.io/apiserver/pkg/server/httplog"
+	"k8s.io/component-base/metrics/prometheus/slis"
 	"k8s.io/klog/v2"
 )
 
@@ -237,6 +239,7 @@ func handleRootHealth(name string, firstTimeHealthy func(), checks ...HealthChec
 				continue
 			}
 			if err := check.Check(r); err != nil {
+				slis.ObserveHealthcheck(context.Background(), check.Name(), name, slis.Error)
 				// don't include the error since this endpoint is public.  If someone wants more detail
 				// they should have explicit permission to the detailed checks.
 				fmt.Fprintf(&individualCheckOutput, "[-]%s failed: reason withheld\n", check.Name())
@@ -244,6 +247,7 @@ func handleRootHealth(name string, firstTimeHealthy func(), checks ...HealthChec
 				fmt.Fprintf(&failedVerboseLogOutput, "[-]%s failed: %v\n", check.Name(), err)
 				failedChecks = append(failedChecks, check.Name())
 			} else {
+				slis.ObserveHealthcheck(context.Background(), check.Name(), name, slis.Success)
 				fmt.Fprintf(&individualCheckOutput, "[+]%s ok\n", check.Name())
 			}
 		}