Expose new /metrics endpoint to allow monitoring of addon-resizer

addon-resizer/Makefile

@@ -22,7 +22,7 @@ ARCH ?= amd64
 export DOCKER_CLI_EXPERIMENTAL=enabled
 
 GOARM=7
-GOLANG_VERSION = 1.21
+GOLANG_VERSION = 1.22
 REGISTRY = gcr.io/k8s-staging-autoscaling
 IMGNAME = addon-resizer
 IMAGE = $(REGISTRY)/$(IMGNAME)

addon-resizer/go.mod

@@ -1,24 +1,27 @@
 module k8s.io/autoscaler/addon-resizer
 
-go 1.21
+go 1.22.0
 
 require (
 	github.com/google/go-cmp v0.6.0
 	github.com/prometheus/client_model v0.6.1
 	github.com/prometheus/common v0.52.3
 	github.com/spf13/pflag v1.0.5
 	gopkg.in/inf.v0 v0.9.1
-	k8s.io/api v0.29.4
-	k8s.io/apimachinery v0.29.4
-	k8s.io/client-go v0.29.4
-	k8s.io/klog/v2 v2.110.1
+	k8s.io/api v0.30.1
+	k8s.io/apimachinery v0.30.1
+	k8s.io/client-go v0.30.1
+	k8s.io/klog/v2 v2.120.1
 )
 
 require (
+	github.com/beorn7/perks v1.0.1 // indirect
+	github.com/blang/semver/v4 v4.0.0 // indirect
+	github.com/cespare/xxhash/v2 v2.2.0 // indirect
 	github.com/davecgh/go-spew v1.1.1 // indirect
 	github.com/emicklei/go-restful/v3 v3.11.0 // indirect
 	github.com/evanphx/json-patch v4.12.0+incompatible // indirect
-	github.com/go-logr/logr v1.3.0 // indirect
+	github.com/go-logr/logr v1.4.1 // indirect
 	github.com/go-openapi/jsonpointer v0.19.6 // indirect
 	github.com/go-openapi/jsonreference v0.20.2 // indirect
 	github.com/go-openapi/swag v0.22.3 // indirect
@@ -36,6 +39,8 @@ require (
 	github.com/modern-go/reflect2 v1.0.2 // indirect
 	github.com/munnerz/goautoneg v0.0.0-20191010083416-a7dc8b61c822 // indirect
 	github.com/pkg/errors v0.9.1 // indirect
+	github.com/prometheus/client_golang v1.19.0 // indirect
+	github.com/prometheus/procfs v0.12.0 // indirect
 	golang.org/x/net v0.23.0 // indirect
 	golang.org/x/oauth2 v0.18.0 // indirect
 	golang.org/x/sys v0.18.0 // indirect
@@ -46,7 +51,8 @@ require (
 	google.golang.org/protobuf v1.33.0 // indirect
 	gopkg.in/yaml.v2 v2.4.0 // indirect
 	gopkg.in/yaml.v3 v3.0.1 // indirect
-	k8s.io/kube-openapi v0.0.0-20231010175941-2dd684a91f00 // indirect
+	k8s.io/component-base v0.30.1 // indirect
+	k8s.io/kube-openapi v0.0.0-20240228011516-70dd3763d340 // indirect
 	k8s.io/utils v0.0.0-20230726121419-3b25d923346b // indirect
 	sigs.k8s.io/json v0.0.0-20221116044647-bc3834ca7abd // indirect
 	sigs.k8s.io/structured-merge-diff/v4 v4.4.1 // indirect

addon-resizer/go.sum

@@ -1,3 +1,9 @@
+github.com/beorn7/perks v1.0.1 h1:VlbKKnNfV8bJzeqoa4cOKqO6bYr3WgKZxO8Z16+hsOM=
+github.com/beorn7/perks v1.0.1/go.mod h1:G2ZrVWU2WbWT9wwq4/hrbKbnv/1ERSJQ0ibhJ6rlkpw=
+github.com/blang/semver/v4 v4.0.0 h1:1PFHFE6yCCTv8C1TeyNNarDzntLi7wMI5i/pzqYIsAM=
+github.com/blang/semver/v4 v4.0.0/go.mod h1:IbckMUScFkM3pff0VJDNKRiT6TG/YpiHIM2yvyW5YoQ=
+github.com/cespare/xxhash/v2 v2.2.0 h1:DC2CZ1Ep5Y4k3ZQ899DldepgrayRUGE6BBZ/cd9Cj44=
+github.com/cespare/xxhash/v2 v2.2.0/go.mod h1:VGX0DQ3Q6kWi7AoAeZDth3/j3BFtOZR5XLFGgcrjCOs=
 github.com/creack/pty v1.1.9/go.mod h1:oKZEueFk5CKHvIhNR5MUki03XCEU+Q6VDXinZuGJ33E=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
@@ -8,6 +14,8 @@ github.com/evanphx/json-patch v4.12.0+incompatible h1:4onqiflcdA9EOZ4RxV643DvftH
 github.com/evanphx/json-patch v4.12.0+incompatible/go.mod h1:50XU6AFN0ol/bzJsmQLiYLvXMP4fmwYFNcr97nuDLSk=
 github.com/go-logr/logr v1.3.0 h1:2y3SDp0ZXuc6/cjLSZ+Q3ir+QB9T/iG5yYRXqsagWSY=
 github.com/go-logr/logr v1.3.0/go.mod h1:9T104GzyrTigFIr8wt5mBrctHMim0Nb2HLGrmQ40KvY=
+github.com/go-logr/logr v1.4.1 h1:pKouT5E8xu9zeFC39JXRDukb6JFQPXM5p5I91188VAQ=
+github.com/go-logr/logr v1.4.1/go.mod h1:9T104GzyrTigFIr8wt5mBrctHMim0Nb2HLGrmQ40KvY=
 github.com/go-openapi/jsonpointer v0.19.6 h1:eCs3fxoIi3Wh6vtgmLTOjdhSpiqphQ+DaPn38N2ZdrE=
 github.com/go-openapi/jsonpointer v0.19.6/go.mod h1:osyAmYz/mB/C3I+WsTTSgw1ONzaLJoLCyoi6/zppojs=
 github.com/go-openapi/jsonreference v0.20.2 h1:3sVjiK66+uXK/6oQ8xgcRKcFgQ5KXa2KvnJRumpMGbE=
@@ -61,16 +69,22 @@ github.com/munnerz/goautoneg v0.0.0-20191010083416-a7dc8b61c822 h1:C3w9PqII01/Oq
 github.com/munnerz/goautoneg v0.0.0-20191010083416-a7dc8b61c822/go.mod h1:+n7T8mK8HuQTcFwEeznm/DIxMOiR9yIdICNftLE1DvQ=
 github.com/onsi/ginkgo/v2 v2.13.0 h1:0jY9lJquiL8fcf3M4LAXN5aMlS/b2BV86HFFPCPMgE4=
 github.com/onsi/ginkgo/v2 v2.13.0/go.mod h1:TE309ZR8s5FsKKpuB1YAQYBzCaAfUgatB/xlT/ETL/o=
+github.com/onsi/ginkgo/v2 v2.15.0 h1:79HwNRBAZHOEwrczrgSOPy+eFTTlIGELKy5as+ClttY=
 github.com/onsi/gomega v1.29.0 h1:KIA/t2t5UBzoirT4H9tsML45GEbo3ouUnBHsCfD2tVg=
 github.com/onsi/gomega v1.29.0/go.mod h1:9sxs+SwGrKI0+PWe4Fxa9tFQQBG5xSsSbMXOI8PPpoQ=
+github.com/onsi/gomega v1.31.0 h1:54UJxxj6cPInHS3a35wm6BK/F9nHYueZ1NVujHDrnXE=
 github.com/pkg/errors v0.9.1 h1:FEBLx1zS214owpjy7qsBeixbURkuhQAwrK5UwLGTwt4=
 github.com/pkg/errors v0.9.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/prometheus/client_golang v1.19.0 h1:ygXvpU1AoN1MhdzckN+PyD9QJOSD4x7kmXYlnfbA6JU=
+github.com/prometheus/client_golang v1.19.0/go.mod h1:ZRM9uEAypZakd+q/x7+gmsvXdURP+DABIEIjnmDdp+k=
 github.com/prometheus/client_model v0.6.1 h1:ZKSh/rekM+n3CeS952MLRAdFwIKqeY8b62p8ais2e9E=
 github.com/prometheus/client_model v0.6.1/go.mod h1:OrxVMOVHjw3lKMa8+x6HeMGkHMQyHDk9E3jmP2AmGiY=
 github.com/prometheus/common v0.52.3 h1:5f8uj6ZwHSscOGNdIQg6OiZv/ybiK2CO2q2drVZAQSA=
 github.com/prometheus/common v0.52.3/go.mod h1:BrxBKv3FWBIGXw89Mg1AeBq7FSyRzXWI3l3e7W3RN5U=
+github.com/prometheus/procfs v0.12.0 h1:jluTpSng7V9hY0O2R9DzzJHYb2xULk9VTR1V1R/k6Bo=
+github.com/prometheus/procfs v0.12.0/go.mod h1:pcuDEFsWDnvcgNzo4EEweacyhjeA9Zk3cnaOZAZEfOo=
 github.com/rogpeppe/go-internal v1.10.0 h1:TMyTOH3F/DB16zRVcYyreMH6GnZZrwQVAoYjRBZyWFQ=
 github.com/rogpeppe/go-internal v1.10.0/go.mod h1:UQnix2H7Ngw/k4C5ijL5+65zddjncjaFoBhdsK/akog=
 github.com/spf13/pflag v1.0.5 h1:iy+VFUOCP1a+8yFto/drg2CJ5u0yRoB7fZw3DKv/JXA=
@@ -123,6 +137,7 @@ golang.org/x/tools v0.0.0-20200619180055-7c47624df98f/go.mod h1:EkVYQZoAsY45+roY
 golang.org/x/tools v0.0.0-20210106214847-113979e3529a/go.mod h1:emZCQorbCU4vsT4fOWvOPXz4eW1wZW4PmDk9uLelYpA=
 golang.org/x/tools v0.16.1 h1:TLyB3WofjdOEepBHAU20JdNC1Zbg87elYofWYAY5oZA=
 golang.org/x/tools v0.16.1/go.mod h1:kYVVN6I1mBNoB1OX+noeBjbRk4IUEPa7JJ+TJMEooJ0=
+golang.org/x/tools v0.18.0 h1:k8NLag8AGHnn+PHbl7g43CtqZAwG60vZkLqgyZgIHgQ=
 golang.org/x/xerrors v0.0.0-20190717185122-a985d3407aa7/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 golang.org/x/xerrors v0.0.0-20191011141410-1b5146add898/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
@@ -144,14 +159,26 @@ gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
 gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
 k8s.io/api v0.29.4 h1:WEnF/XdxuCxdG3ayHNRR8yH3cI1B/llkWBma6bq4R3w=
 k8s.io/api v0.29.4/go.mod h1:DetSv0t4FBTcEpfA84NJV3g9a7+rSzlUHk5ADAYHUv0=
+k8s.io/api v0.30.1 h1:kCm/6mADMdbAxmIh0LBjS54nQBE+U4KmbCfIkF5CpJY=
+k8s.io/api v0.30.1/go.mod h1:ddbN2C0+0DIiPntan/bye3SW3PdwLa11/0yqwvuRrJM=
 k8s.io/apimachinery v0.29.4 h1:RaFdJiDmuKs/8cm1M6Dh1Kvyh59YQFDcFuFTSmXes6Q=
 k8s.io/apimachinery v0.29.4/go.mod h1:i3FJVwhvSp/6n8Fl4K97PJEP8C+MM+aoDq4+ZJBf70Y=
+k8s.io/apimachinery v0.30.1 h1:ZQStsEfo4n65yAdlGTfP/uSHMQSoYzU/oeEbkmF7P2U=
+k8s.io/apimachinery v0.30.1/go.mod h1:iexa2somDaxdnj7bha06bhb43Zpa6eWH8N8dbqVjTUc=
 k8s.io/client-go v0.29.4 h1:79ytIedxVfyXV8rpH3jCBW0u+un0fxHDwX5F9K8dPR8=
 k8s.io/client-go v0.29.4/go.mod h1:kC1thZQ4zQWYwldsfI088BbK6RkxK+aF5ebV8y9Q4tk=
+k8s.io/client-go v0.30.1 h1:uC/Ir6A3R46wdkgCV3vbLyNOYyCJ8oZnjtJGKfytl/Q=
+k8s.io/client-go v0.30.1/go.mod h1:wrAqLNs2trwiCH/wxxmT/x3hKVH9PuV0GGW0oDoHVqc=
+k8s.io/component-base v0.30.1 h1:bvAtlPh1UrdaZL20D9+sWxsJljMi0QZ3Lmw+kmZAaxQ=
+k8s.io/component-base v0.30.1/go.mod h1:e/X9kDiOebwlI41AvBHuWdqFriSRrX50CdwA9TFaHLI=
 k8s.io/klog/v2 v2.110.1 h1:U/Af64HJf7FcwMcXyKm2RPM22WZzyR7OSpYj5tg3cL0=
 k8s.io/klog/v2 v2.110.1/go.mod h1:YGtd1984u+GgbuZ7e08/yBuAfKLSO0+uR1Fhi6ExXjo=
+k8s.io/klog/v2 v2.120.1 h1:QXU6cPEOIslTGvZaXvFWiP9VKyeet3sawzTOvdXb4Vw=
+k8s.io/klog/v2 v2.120.1/go.mod h1:3Jpz1GvMt720eyJH1ckRHK1EDfpxISzJ7I9OYgaDtPE=
 k8s.io/kube-openapi v0.0.0-20231010175941-2dd684a91f00 h1:aVUu9fTY98ivBPKR9Y5w/AuzbMm96cd3YHRTU83I780=
 k8s.io/kube-openapi v0.0.0-20231010175941-2dd684a91f00/go.mod h1:AsvuZPBlUDVuCdzJ87iajxtXuR9oktsTctW/R9wwouA=
+k8s.io/kube-openapi v0.0.0-20240228011516-70dd3763d340 h1:BZqlfIlq5YbRMFko6/PM7FjZpUb45WallggurYhKGag=
+k8s.io/kube-openapi v0.0.0-20240228011516-70dd3763d340/go.mod h1:yD4MZYeKMBwQKVht279WycxKyM84kkAx2DPrTXaeb98=
 k8s.io/utils v0.0.0-20230726121419-3b25d923346b h1:sgn3ZU783SCgtaSJjpcVVlRqd6GSnlTLKgpAAttJvpI=
 k8s.io/utils v0.0.0-20230726121419-3b25d923346b/go.mod h1:OLgZIPagt7ERELqWJFomSt595RzquPNLL48iOWgYOg0=
 sigs.k8s.io/json v0.0.0-20221116044647-bc3834ca7abd h1:EDPBXCAspyGV4jQlpZSudPeMmr1bNJefnuqLsRAsHZo=

addon-resizer/nanny/main/pod_nanny.go

@@ -27,6 +27,7 @@ import (
 
 	"k8s.io/autoscaler/addon-resizer/healthcheck"
 	"k8s.io/autoscaler/addon-resizer/nanny"
+	"k8s.io/autoscaler/addon-resizer/nanny/metrics"
 
 	"path/filepath"
 
@@ -76,6 +77,9 @@ var (
 	leaderElectionLeaseDuration = flag.Duration("leader-election-lease-duration", 15*time.Second, "The duration that non-leader candidates will wait after observing a leadership renewal until attempting to acquire leadership of a led but unrenewed leader slot. This is effectively the maximum duration that a leader can be stopped before it is replaced by another candidate.")
 	leaderElectionRenewDeadline = flag.Duration("leader-election-renew-deadline", 10*time.Second, "The duration that the acting master will retry refreshing leadership before giving up.")
 	leaderElectionRetryPeriod   = flag.Duration("leader-election-retry-period", 2*time.Second, "The duration to wait between tries of actions.")
+	// Metrics endpoint flags.
+	address       = flag.String("address", ":8945", "The address to expose Prometheus metrics.")
+	exposeMetrics = flag.Bool("expose-metrics", false, "When true, exposes Prometheus metrics on the port specified by the address flag.")
 )
 
 func main() {
@@ -84,6 +88,12 @@ func main() {
 	klog.Infof("Version: %s", nanny.AddonResizerVersion)
 	flag.Parse()
 
+	if *exposeMetrics {
+		// Register a handler on the provided address.
+		metrics.Initialize(*address)
+	}
+	metrics.Register()
+
 	// Perform further validation of flags.
 	if *deployment == "" {
 		klog.Fatal("Must specify a deployment.")

addon-resizer/nanny/metrics/metrics.go

@@ -0,0 +1,59 @@
+/*
+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 metrics - metrics for addon-resizer.
+package metrics
+
+import (
+	"net/http"
+
+	"github.com/prometheus/client_golang/prometheus"
+	"github.com/prometheus/client_golang/prometheus/promhttp"
+
+	_ "k8s.io/component-base/metrics/prometheus/restclient" // for client-go metrics registration
+	"k8s.io/klog/v2"
+)
+
+const (
+	namespace = "addon_resizer"
+)
+
+var (
+	executionOutcome = prometheus.NewCounterVec(
+		prometheus.CounterOpts{
+			Namespace: namespace,
+			Name:      "execution_outcome",
+			Help:      "Count of execution loop outcomes.",
+		}, []string{"outcome"},
+	)
+)
+
+// Initialize sets up Prometheus to expose metrics.
+func Initialize(address string) {
+	go func() {
+		http.Handle("/metrics", promhttp.Handler())
+		err := http.ListenAndServe(address, nil)
+		klog.Fatalf("Failed to start metrics: %v", err)
+	}()
+}
+
+func Register() {
+	prometheus.MustRegister(executionOutcome)
+}
+
+func ObserveOutcome(outcome string) {
+	executionOutcome.WithLabelValues(outcome).Inc()
+}

addon-resizer/nanny/nanny_lib.go

@@ -27,6 +27,7 @@ import (
 	inf "gopkg.in/inf.v0"
 	corev1 "k8s.io/api/core/v1"
 	"k8s.io/autoscaler/addon-resizer/healthcheck"
+	"k8s.io/autoscaler/addon-resizer/nanny/metrics"
 	"k8s.io/klog/v2"
 )
 
@@ -151,6 +152,7 @@ func updateResources(k8s KubernetesClient, est ResourceEstimator, now, lastChang
 
 	if err != nil {
 		klog.Error(err)
+		metrics.ObserveOutcome("error_getting_count")
 		return noChange
 	}
 	klog.V(4).Infof("The cluster size is %d", num)
@@ -159,6 +161,7 @@ func updateResources(k8s KubernetesClient, est ResourceEstimator, now, lastChang
 	resources, err := k8s.ContainerResources()
 	if err != nil {
 		klog.Errorf("Error while querying apiserver for resources: %v", err)
+		metrics.ObserveOutcome("error_getting_resources")
 		return noChange
 	}
 
@@ -171,6 +174,7 @@ func updateResources(k8s KubernetesClient, est ResourceEstimator, now, lastChang
 		if klog.V(4).Enabled() {
 			klog.V(4).Infof("Resources are within the expected limits. Actual: %+v Expected: %+v", jsonOrValue(*resources), jsonOrValue(*expResources))
 		}
+		metrics.ObserveOutcome("resources_within_limits")
 		return noChange
 	}
 
@@ -179,14 +183,17 @@ func updateResources(k8s KubernetesClient, est ResourceEstimator, now, lastChang
 		if prevResult != postpone {
 			klog.Infof("Resources are not within the expected limits, Actual: %+v, accepted range: %+v. Skipping resource update because of scale up/down delay", jsonOrValue(*resources), jsonOrValue(*expResources))
 		}
+		metrics.ObserveOutcome("scale_up_down_delay")
 		return postpone
 	}
 
 	klog.Infof("Resources are not within the expected limits, updating the deployment. Actual: %+v Expected: %+v. Resource will be updated.", jsonOrValue(*resources), jsonOrValue(*expResources))
 	if err := k8s.UpdateDeployment(expResources); err != nil {
 		klog.Error(err)
+		metrics.ObserveOutcome("error_updating_deployment")
 		return noChange
 	}
+	metrics.ObserveOutcome("updated_resources")
 	return overwrite
 }