feat: use deployment replica check from kubescore

charts/steadybit-extension-kubernetes/Chart.yaml

@@ -1,7 +1,7 @@
 apiVersion: v2
 name: steadybit-extension-kubernetes
 description: Steadybit Kubernetes extension Helm chart for Kubernetes.
-version: 1.4.49
+version: 1.4.50
 appVersion: latest
 home: https://www.steadybit.com/
 icon: https://steadybit-website-assets.s3.amazonaws.com/logo-symbol-transparent.png

charts/steadybit-extension-kubernetes/templates/clusterrole.yaml

@@ -31,6 +31,15 @@ rules:
       - get
       - list
       - watch
+  {{/* Required for Single-Replica-Advice */}}
+  - apiGroups:
+      - autoscaling
+    resources:
+      - horizontalpodautoscalers
+    verbs:
+      - get
+      - list
+      - watch
   {{/* Required for Rollout Restart Attack */}}
   - apiGroups:
       - apps

client/client.go

@@ -10,6 +10,7 @@ import (
 	"github.com/rs/zerolog/log"
 	"golang.org/x/exp/slices"
 	appsv1 "k8s.io/api/apps/v1"
+	autoscalingv2 "k8s.io/api/autoscaling/v2"
 	corev1 "k8s.io/api/core/v1"
 	k8sErrors "k8s.io/apimachinery/pkg/api/errors"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
@@ -18,6 +19,7 @@ import (
 	"k8s.io/client-go/informers"
 	"k8s.io/client-go/kubernetes"
 	listerAppsv1 "k8s.io/client-go/listers/apps/v1"
+	listerAutoscalingv2 "k8s.io/client-go/listers/autoscaling/v2"
 	listerCorev1 "k8s.io/client-go/listers/core/v1"
 	"k8s.io/client-go/rest"
 	"k8s.io/client-go/tools/cache"
@@ -75,6 +77,11 @@ type Client struct {
 		informer cache.SharedIndexInformer
 	}
 
+	hpa struct {
+		lister   listerAutoscalingv2.HorizontalPodAutoscalerLister
+		informer cache.SharedIndexInformer
+	}
+
 	handlers struct {
 		sync.Mutex
 		l []chan<- interface{}
@@ -241,6 +248,20 @@ func (c *Client) Events(since time.Time) *[]corev1.Event {
 	return &result
 }
 
+func (c *Client) HorizontalPodAutoscalerByNamespaceAndDeployment(namespace string, reference string) *autoscalingv2.HorizontalPodAutoscaler {
+	hpas, err := c.hpa.lister.HorizontalPodAutoscalers(namespace).List(labels.Everything())
+	if err != nil {
+		log.Error().Err(err).Msgf("Error while fetching horizontal pod autoscalers")
+		return nil
+	}
+	for _, hpa := range hpas {
+		if hpa.Spec.ScaleTargetRef.Kind == "Deployment" && hpa.Spec.ScaleTargetRef.Name == reference {
+			return hpa
+		}
+	}
+	return nil
+}
+
 func logGetError(resource string, err error) {
 	if err != nil {
 		var t *k8sErrors.StatusError
@@ -368,6 +389,19 @@ func CreateClient(clientset kubernetes.Interface, stopCh <-chan struct{}, rootAp
 		log.Fatal().Msg("failed to add node event handler")
 	}
 
+	if permissions.CanReadHorizontalPodAutoscalers() {
+		hpa := factory.Autoscaling().V2().HorizontalPodAutoscalers()
+		client.hpa.informer = hpa.Informer()
+		client.hpa.lister = hpa.Lister()
+		informerSyncList = append(informerSyncList, client.hpa.informer.HasSynced)
+		if err := client.hpa.informer.SetTransform(transformHPA); err != nil {
+			log.Fatal().Err(err).Msg("Failed to add hpa transformer")
+		}
+		if _, err := client.hpa.informer.AddEventHandler(client.resourceEventHandler); err != nil {
+			log.Fatal().Msg("failed to add hpa event handler")
+		}
+	}
+
 	events := factory.Core().V1().Events()
 	client.event.informer = events.Informer()
 	informerSyncList = append(informerSyncList, client.event.informer.HasSynced)

client/permissions.go

@@ -46,6 +46,7 @@ var requiredPermissions = []requiredPermission{
 	{group: "apps", resource: "replicasets", verbs: []string{"get", "list", "watch"}, allowGracefulFailure: false},
 	{group: "apps", resource: "daemonsets", verbs: []string{"get", "list", "watch"}, allowGracefulFailure: false},
 	{group: "apps", resource: "statefulsets", verbs: []string{"get", "list", "watch"}, allowGracefulFailure: false},
+	{group: "autoscaling", resource: "horizontalpodautoscalers", verbs: []string{"get", "list", "watch"}, allowGracefulFailure: true},
 	{group: "", resource: "services", verbs: []string{"get", "list", "watch"}, allowGracefulFailure: false},
 	{group: "", resource: "pods", verbs: []string{"get", "list", "watch"}, allowGracefulFailure: false},
 	{group: "", resource: "nodes", verbs: []string{"get", "list", "watch"}, allowGracefulFailure: false},
@@ -133,6 +134,13 @@ func (p *PermissionCheckResult) hasPermissions(requiredPermissions []string) boo
 	return true
 }
 
+func (p *PermissionCheckResult) CanReadHorizontalPodAutoscalers() bool {
+	return p.hasPermissions([]string{
+		"autoscaling/horizontalpodautoscalers/get",
+		"autoscaling/horizontalpodautoscalers/list",
+		"autoscaling/horizontalpodautoscalers/watch"})
+}
+
 func (p *PermissionCheckResult) IsRolloutRestartPermitted() bool {
 	return p.hasPermissions([]string{
 		"apps/deployments/patch",

extadvice/advice.go

@@ -210,11 +210,11 @@ func GetAdviceDescriptionSingleReplica() advice_kit_api.AdviceDefinition {
 		Label:                     "Redundant Pod Deployment",
 		Version:                   extbuild.GetSemverVersionStringOrUnknown(),
 		Icon:                      "data:image/svg+xml,%3Csvg%20width%3D%2224%22%20height%3D%2224%22%20viewBox%3D%220%200%2024%2024%22%20fill%3D%22none%22%20xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F2000%2Fsvg%22%3E%0A%3Cpath%20d%3D%22M11.9436%207.04563C12.1262%206.98477%2012.3235%206.98477%2012.5061%207.04563L17.8407%208.82395C18.2037%208.94498%2018.4486%209.28468%2018.4485%209.66728C18.4485%2010.0499%2018.2036%2010.3895%2017.8405%2010.5105L12.5059%2012.2877C12.3235%2012.3485%2012.1262%2012.3485%2011.9438%2012.2877L6.60918%2010.5105C6.24611%2010.3895%206.00119%2010.0499%206.00116%209.66728C6.00112%209.28468%206.24598%208.94498%206.60902%208.82395L11.9436%207.04563Z%22%20fill%3D%22%231D2632%22%2F%3E%0A%3Cpath%20d%3D%22M7.20674%2013.2736C6.68268%2013.0989%206.11622%2013.3821%205.94153%2013.9062C5.76684%2014.4302%206.05007%2014.9967%206.57414%2015.1714L11.9087%2016.9496C12.114%2017.018%2012.336%2017.018%2012.5413%2016.9496L17.8759%2015.1714C18.4%2014.9967%2018.6832%2014.4302%2018.5085%2013.9062C18.3338%2013.3821%2017.7674%2013.0989%2017.2433%2013.2736L12.225%2014.9463L7.20674%2013.2736Z%22%20fill%3D%22%231D2632%22%2F%3E%0A%3Cpath%20fill-rule%3D%22evenodd%22%20clip-rule%3D%22evenodd%22%20d%3D%22M11.6491%201.06354C11.8754%200.97882%2012.1246%200.97882%2012.3509%201.06354L22.3506%204.80836C22.7412%204.95463%2023%205.32784%2023%205.74482V18.2552C23%2018.6722%2022.7412%2019.0454%2022.3506%2019.1916L12.3509%2022.9365C12.1246%2023.0212%2011.8754%2023.0212%2011.6491%2022.9365L1.64938%2019.1916C1.2588%2019.0454%201%2018.6722%201%2018.2552V5.74482C1%205.32784%201.2588%204.95463%201.64938%204.80836L11.6491%201.06354ZM3.00047%206.43809V17.5619L12%2020.9321L20.9995%2017.5619V6.43809L12%203.06785L3.00047%206.43809Z%22%20fill%3D%22%231D2632%22%2F%3E%0A%3C%2Fsvg%3E%0A",
-		Tags:                      &[]string{"kubernetes", "deployment", "statefulset", "replica", "pod"},
-		AssessmentQueryApplicable: "target.type=\"" + extdeployment.DeploymentTargetType + "\" OR target.type=\"" + extstatefulset.StatefulSetTargetType + "\"",
+		Tags:                      &[]string{"kubernetes", "deployment", "replica", "pod"},
+		AssessmentQueryApplicable: "target.type=\"" + extdeployment.DeploymentTargetType + "\" AND k8s.specification.has-multiple-replica IS PRESENT",
 		Status: advice_kit_api.AdviceDefinitionStatus{
 			ActionNeeded: advice_kit_api.AdviceDefinitionStatusActionNeeded{
-				AssessmentQuery: "k8s.specification.replicas IS NOT PRESENT OR k8s.specification.replicas = \"1\"",
+				AssessmentQuery: "k8s.specification.has-multiple-replica=\"false\"",
 				Description: advice_kit_api.AdviceDefinitionStatusActionNeededDescription{
 					Instruction: ReadAdviceFile(SingleReplicaContent, "single_replica/instructions.md"),
 					Motivation:  ReadAdviceFile(SingleReplicaContent, "single_replica/motivation.md"),

extadvice/single_replica/instructions.md

@@ -17,3 +17,6 @@ spec:
       tier: ${target.steadybit.label:normal}
 ```
 **If you increase the replica we strongly advice you to check if this is supported by your application.**
+
+---
+This advice is powered by [kube-score](https://kube-score.com/).

extcommon/kubescore.go

@@ -11,6 +11,7 @@ import (
 	"github.com/zegl/kube-score/scorecard"
 	"io"
 	appsv1 "k8s.io/api/apps/v1"
+	autoscalingv2 "k8s.io/api/autoscaling/v2"
 	corev1 "k8s.io/api/core/v1"
 	"k8s.io/apimachinery/pkg/runtime"
 	k8sJson "k8s.io/apimachinery/pkg/runtime/serializer/json"
@@ -37,7 +38,7 @@ type kubeScoreInput interface {
 	GetNamespace() string
 }
 
-func GetKubeScoreForDeployment(deployment *appsv1.Deployment, services []*corev1.Service) map[string][]string {
+func GetKubeScoreForDeployment(deployment *appsv1.Deployment, services []*corev1.Service, hpa *autoscalingv2.HorizontalPodAutoscaler) map[string][]string {
 	deployment.APIVersion = "apps/v1"
 	deployment.Kind = "Deployment"
 	inputs := make([]kubeScoreInput, 0)
@@ -47,6 +48,11 @@ func GetKubeScoreForDeployment(deployment *appsv1.Deployment, services []*corev1
 		service.Kind = "Service"
 		inputs = append(inputs, service)
 	}
+	if hpa != nil {
+		hpa.APIVersion = "autoscaling/v2"
+		hpa.Kind = "HorizontalPodAutoscaler"
+		inputs = append(inputs, hpa)
+	}
 
 	attributes := map[string][]string{}
 
@@ -58,6 +64,7 @@ func GetKubeScoreForDeployment(deployment *appsv1.Deployment, services []*corev1
 	addContainerBasedScore(scores, attributes, "container-image-pull-policy", "k8s.container.image.without-image-pull-policy-always")
 	addSimpleScore(scores, attributes, "deployment-has-host-podantiaffinity", "k8s.specification.has-host-podantiaffinity")
 	addSimpleScore(scores, attributes, "deployment-strategy", "k8s.specification.has-rolling-update-strategy")
+	addSimpleScore(scores, attributes, "deployment-replicas", "k8s.specification.has-multiple-replica")
 
 	return attributes
 }

extdeployment/deployment_discovery.go

@@ -15,6 +15,7 @@ import (
 	"github.com/steadybit/extension-kubernetes/extcommon"
 	"github.com/steadybit/extension-kubernetes/extconfig"
 	appsv1 "k8s.io/api/apps/v1"
+	autoscalingv2 "k8s.io/api/autoscaling/v2"
 	corev1 "k8s.io/api/core/v1"
 	"k8s.io/utils/strings/slices"
 	"reflect"
@@ -114,7 +115,11 @@ func (d *deploymentDiscovery) DiscoverTargets(_ context.Context) ([]discovery_ki
 			attributes[key] = value
 		}
 
-		for key, value := range extcommon.GetKubeScoreForDeployment(deployment, d.k8s.ServicesMatchingToPodLabels(deployment.Namespace, deployment.Spec.Template.Labels)) {
+		var hpa *autoscalingv2.HorizontalPodAutoscaler
+		if d.k8s.Permissions().CanReadHorizontalPodAutoscalers() {
+			hpa = d.k8s.HorizontalPodAutoscalerByNamespaceAndDeployment(deployment.Namespace, deployment.Name)
+		}
+		for key, value := range extcommon.GetKubeScoreForDeployment(deployment, d.k8s.ServicesMatchingToPodLabels(deployment.Namespace, deployment.Spec.Template.Labels), hpa) {
 			attributes[key] = value
 		}
 

extdeployment/deployment_discovery_test.go

@@ -271,6 +271,40 @@ func Test_deploymentDiscovery(t *testing.T) {
 				"k8s.specification.has-rolling-update-strategy": {"true"},
 			},
 		},
+		{
+			name: "should report single replica",
+			pods: []*v1.Pod{testPod("aaaaa", nil)},
+			deployment: testDeployment(func(deployment *appsv1.Deployment) {
+				deployment.Spec.Replicas = extutil.Ptr(int32(1))
+			}),
+			service: testService(nil),
+			expectedAttributes: map[string][]string{
+				"k8s.specification.has-multiple-replica": {"false"},
+			},
+		},
+		{
+			name:       "should report multiple replicas",
+			pods:       []*v1.Pod{testPod("aaaaa", nil)},
+			deployment: testDeployment(nil),
+			service:    testService(nil),
+			expectedAttributes: map[string][]string{
+				"k8s.specification.has-multiple-replica": {"true"},
+			},
+		},
+		{
+			name:                      "should not report multiple replicas if no service is defined",
+			pods:                      []*v1.Pod{testPod("aaaaa", nil)},
+			deployment:                testDeployment(nil),
+			expectedAttributesAbsence: []string{"k8s.specification.has-multiple-replica"},
+		},
+		{
+			name:                      "should not report multiple replicas if targeted by hpa",
+			pods:                      []*v1.Pod{testPod("aaaaa", nil)},
+			deployment:                testDeployment(nil),
+			service:                   testService(nil),
+			hpa:                       testHPA(nil),
+			expectedAttributesAbsence: []string{"k8s.specification.has-multiple-replica"},
+		},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
@@ -349,6 +383,31 @@ func Test_deploymentDiscovery(t *testing.T) {
 	}
 }
 
+func testHPA(modifier func(autoscaler *autoscalingv2.HorizontalPodAutoscaler)) *autoscalingv2.HorizontalPodAutoscaler {
+	autoscaler := &autoscalingv2.HorizontalPodAutoscaler{
+		TypeMeta: metav1.TypeMeta{
+			Kind:       "HorizontalPodAutoscaler",
+			APIVersion: "autoscaling/v2",
+		},
+		ObjectMeta: metav1.ObjectMeta{
+			Name:      "shop",
+			Namespace: "default",
+		},
+		Spec: autoscalingv2.HorizontalPodAutoscalerSpec{
+			ScaleTargetRef: autoscalingv2.CrossVersionObjectReference{
+				Kind:       "Deployment",
+				Name:       "shop",
+				APIVersion: "apps/v1",
+			},
+		},
+	}
+	if modifier != nil {
+		modifier(autoscaler)
+	}
+
+	return autoscaler
+}
+
 func testDeployment(modifier func(*appsv1.Deployment)) *appsv1.Deployment {
 	deployment := &appsv1.Deployment{
 		TypeMeta: metav1.TypeMeta{