Install KEDA

Install

• https://keda.sh/docs/latest/deploy/

helm repo add kedacore https://kedacore.github.io/charts
helm repo update
helm install keda kedacore/keda --namespace keda --create-namespace

$ kubectl get pods -n keda -w
NAME                                               READY   STATUS    RESTARTS      AGE
keda-operator-54bcdc6446-rf9rc                     1/1     Running   8 (30h ago)   2d21h
keda-operator-metrics-apiserver-74487bb99f-ztqcr   1/1     Running   0             2d21h

動作確認

nginx podでアクセス増減によるscale out/in を確認する

Point

• HPAリソースを作成する前にDeploymentリソースの spec.replica を削除する
  • https://kubernetes.io/docs/tasks/run-application/horizontal-pod-autoscale/#migrating-deployments-and-statefulsets-to-horizontal-autoscaling
• nginx stub_statusを有効にする
  • http://nginx.org/en/docs/http/ngx_http_stub_status_module.html
• nginx exporterをside carとして追加する
  • https://github.com/nginxinc/nginx-prometheus-exporter
  • -nginx.scrape-uri=http://localhost/nginx_status を追加する
  • scrape用Portとして 9113 をexportする

手順

1. deploy

   deployment.yaml

   apiVersion: v1
   kind: ConfigMap
   metadata:
     name: nginx-conf
   data:
     nginx.conf: |
       user nginx;
       worker_processes  1;
       error_log  /var/log/nginx/error.log;
       events {
         worker_connections  1024;
       }
       http {
         server {
             listen       80;
             server_name  _;
   
             location / {
                 root   html;
                 index  index.html index.htm;
             }
   
             location /nginx_status {
                 stub_status on;
                 access_log off;
                 allow 127.0.0.1;
                 deny all;
             }
   
         }
       }
   
   ---
   apiVersion: apps/v1
   kind: Deployment
   metadata:
     name: nginx-deployment
   spec:
     selector:
       matchLabels:
         app: nginx
   
     # HPA導入時にはDeploymentのspec.replicasを削除することが推奨されている
     # refs https://kubernetes.io/docs/tasks/run-application/horizontal-pod-autoscale/#api-object
     # replicas: 2
   
     template:
       metadata:
         annotations:
           prometheus.io/scrape: 'true'
           prometheus.io/port: '9113'
         labels:
           app: nginx
       spec:
         volumes:
         - name: nginx-conf
           configMap:
             name: nginx-conf
             items:
               - key: nginx.conf
                 path: nginx.conf
         containers:
         - name: nginx
           image: nginx:1.14.2
           ports:
           - containerPort: 80
           volumeMounts:
           - mountPath: /etc/nginx/nginx.conf
             readOnly: true
             name: nginx-conf
             subPath: nginx.conf
         - name: nginx-exporter
           image: nginx/nginx-prometheus-exporter:0.11.0
           args:
             - -nginx.scrape-uri=http://localhost/nginx_status
           ports:
             - containerPort: 9113
   
   ---
   apiVersion: keda.sh/v1alpha1
   kind: ScaledObject
   metadata:
     name: nginx-scaledobject
     labels:
       deploymentName: nginx-deployment
   
   spec:
     fallback:
       failureThreshold: 3
       replicas: 5
     minReplicaCount: 1
     maxReplicaCount: 5
     scaleTargetRef:
       name: nginx-deployment
     triggers:
     - type: prometheus
       metadata:
         serverAddress: http://prometheus-server.monitoring.svc.cluster.local
         metricName: nginx_http_requests_total
         query: sum(rate(nginx_http_requests_total{app="nginx"}[2m]))
         threshold: '3'
   

   kubectl apply -f deployment.yaml
   

2. Deploymentリソースの Replicas を削除

   • HPAリソースの Replicas と Deploymentリソースの Replicas が競合してしまう

   • https://kubernetes.io/docs/tasks/run-application/horizontal-pod-autoscale/#migrating-deployments-and-statefulsets-to-horizontal-autoscaling

     1. kubectl.kubernetes.io/last-applied-configuration annotationsに spec.replicas が存在することを確認

     $ kubectl get deployment nginx-deployment -o yaml | yq .metadata.annotations
     deployment.kubernetes.io/revision: "1"
     kubectl.kubernetes.io/last-applied-configuration: |
       {"apiVersion":"apps/v1","kind":"Deployment","metadata":{"annotations":{},"name":"nginx-deployment","namespace":"default"},"spec":{"replicas":2,"selector":{"matchLabels":{"app":"nginx"}},"template":{"metadata":{"annotations":{"prometheus.io/port":"9113","prometheus.io/scrape":"true"},"labels":{"app":"nginx"}},"spec":{"containers":[{"image":"nginx:1.14.2","name":"nginx","ports":[{"containerPort":80}],"volumeMounts":[{"mountPath":"/etc/nginx/nginx.conf","name":"nginx-conf","readOnly":true,"subPath":"nginx.conf"}]},{"args":["-nginx.scrape-uri=http://localhost/nginx_status"],"image":"nginx/nginx-prometheus-exporter:0.11.0","name":"nginx-exporter","ports":[{"containerPort":9113}]}],"volumes":[{"configMap":{"items":[{"key":"nginx.conf","path":"nginx.conf"}],"name":"nginx-conf"},"name":"nginx-conf"}]}}}}
     

     2. kubectl.kubernetes.io/last-applied-configuration annotationsの spec.replicas を削除

     kubectl apply edit-last-applied deployment/nginx-deployment
     

     3. kubectl.kubernetes.io/last-applied-configuration annotationsから spec.replicas が削除されていることを確認

     $ kubectl get deployment nginx-deployment -o yaml | yq .metadata.annotations
     deployment.kubernetes.io/revision: "1"
     kubectl.kubernetes.io/last-applied-configuration: |
       {"apiVersion":"apps/v1","kind":"Deployment","metadata":{"annotations":{},"name":"nginx-deployment","namespace":"default"},"spec":{"selector":{"matchLabels":{"app":"nginx"}},"template":{"metadata":{"annotations":{"prometheus.io/port":"9113","prometheus.io/scrape":"true"},"labels":{"app":"nginx"}},"spec":{"containers":[{"image":"nginx:1.14.2","name":"nginx","ports":[{"containerPort":80}],"volumeMounts":[{"mountPath":"/etc/nginx/nginx.conf","name":"nginx-conf","readOnly":true,"subPath":"nginx.conf"}]},{"args":["-nginx.scrape-uri=http://localhost/nginx_status"],"image":"nginx/nginx-prometheus-exporter:0.11.0","name":"nginx-exporter","ports":[{"containerPort":9113}]}],"volumes":[{"configMap":{"items":[{"key":"nginx.conf","path":"nginx.conf"}],"name":"nginx-conf"},"name":"nginx-conf"}]}}}}
     

     4. deployment.yaml のDeployment manifestsから spec.replicas を削除する

     vim deployment.yaml
     
     や
     
     sed -i -e '/replicas:\s2/d' deployment.yaml
     
     など
     

3. keda-operator logでScaledObject と HPA が作成されることを確認

   keda-operator logs

   $ kubectl logs -f Deployment/keda-operator -n keda
   
   snip...
   
   2022-11-26T15:37:46Z    INFO    Reconciling ScaledObject        {"controller": "scaledobject", "controllerGroup": "keda.sh", "controllerKind": "ScaledObject", "scaledObject": {"name":"nginx-scaledobject","namespace":"default"}, "namespace": "default", "name": "nginx-scaledobject", "reconcileID": "0085c4c3-03ac-48d9-8b1d-86201dfadf60"}
   2022-11-26T15:37:46Z    INFO    Adding Finalizer for the ScaledObject   {"controller": "scaledobject", "controllerGroup": "keda.sh", "controllerKind": "ScaledObject", "scaledObject": {"name":"nginx-scaledobject","namespace":"default"}, "namespace": "default", "name": "nginx-scaledobject", "reconcileID": "0085c4c3-03ac-48d9-8b1d-86201dfadf60"}
   2022-11-26T15:37:46Z    INFO    Detected resource targeted for scaling  {"controller": "scaledobject", "controllerGroup": "keda.sh", "controllerKind": "ScaledObject", "scaledObject": {"name":"nginx-scaledobject","namespace":"default"}, "namespace": "default", "name": "nginx-scaledobject", "reconcileID": "0085c4c3-03ac-48d9-8b1d-86201dfadf60", "resource": "apps/v1.Deployment", "name": "nginx-deployment"}
   2022-11-26T15:37:46Z    INFO    Creating a new HPA      {"controller": "scaledobject", "controllerGroup": "keda.sh", "controllerKind": "ScaledObject", "scaledObject": {"name":"nginx-scaledobject","namespace":"default"}, "namespace": "default", "name": "nginx-scaledobject", "reconcileID": "0085c4c3-03ac-48d9-8b1d-86201dfadf60", "HPA.Namespace": "default", "HPA.Name": "keda-hpa-nginx-scaledobject"}
   2022-11-26T15:37:46Z    INFO    Initializing Scaling logic according to ScaledObject Specification      {"controller": "scaledobject", "controllerGroup": "keda.sh", "controllerKind": "ScaledObject", "scaledObject": {"name":"nginx-scaledobject","namespace":"default"}, "namespace": "default", "name": "nginx-scaledobject", "reconcileID": "0085c4c3-03ac-48d9-8b1d-86201dfadf60"}
   2022-11-26T15:37:46Z    INFO    Reconciling ScaledObject        {"controller": "scaledobject", "controllerGroup": "keda.sh", "controllerKind": "ScaledObject", "scaledObject": {"name":"nginx-scaledobject","namespace":"default"}, "namespace": "default", "name": "nginx-scaledobject", "reconcileID": "76eb89b7-5ffb-4a53-9165-9a37e184010e"}
   2022-11-26T15:37:46Z    INFO    Reconciling ScaledObject        {"controller": "scaledobject", "controllerGroup": "keda.sh", "controllerKind": "ScaledObject", "scaledObject": {"name":"nginx-scaledobject","namespace":"default"}, "namespace": "default", "name": "nginx-scaledobject", "reconcileID": "645b6f98-fcb8-4710-80b2-2754e673d93b"}
   2022-11-26T15:38:01Z    INFO    Reconciling ScaledObject        {"controller": "scaledobject", "controllerGroup": "keda.sh", "controllerKind": "ScaledObject", "scaledObject": {"name":"nginx-scaledobject","namespace":"default"}, "namespace": "default", "name": "nginx-scaledobject", "reconcileID": "8265c60e-948d-42f7-ae35-11cb7bf7d46f"}
   
   snip...
   

4. 作成されたリソースを確認する

   HPA

   $ kubectl get hpa
   NAME                          REFERENCE                     TARGETS       MINPODS   MAXPODS   REPLICAS   AGE
   keda-hpa-nginx-scaledobject   Deployment/nginx-deployment   17m/3 (avg)   1         5         2          2m45s
   
   $ kubectl get hpa keda-hpa-nginx-scaledobject -o yaml
   apiVersion: autoscaling/v1
   kind: HorizontalPodAutoscaler
   metadata:
     annotations:
       autoscaling.alpha.kubernetes.io/conditions: '[{"type":"AbleToScale","status":"True","lastTransitionTime":"2022-11-26T15:38:01Z","reason":"ReadyForNewScale","message":"recommended
         size matches current size"},{"type":"ScalingActive","status":"True","lastTransitionTime":"2022-12-10T06:28:49Z","reason":"ValidMetricFound","message":"the
         HPA was able to successfully calculate a replica count from external metric
         s0-prometheus-nginx_http_requests_total(\u0026LabelSelector{MatchLabels:map[string]string{scaledobject.keda.sh/name:
         nginx-scaledobject,},MatchExpressions:[]LabelSelectorRequirement{},})"},{"type":"ScalingLimited","status":"False","lastTransitionTime":"2022-11-26T16:27:54Z","reason":"DesiredWithinRange","message":"the
         desired count is within the acceptable range"}]'
       autoscaling.alpha.kubernetes.io/current-metrics: '[{"type":"External","external":{"metricName":"s0-prometheus-nginx_http_requests_total","metricSelector":{"matchLabels":{"scaledobject.keda.sh/name":"nginx-scaledobject"}},"currentValue":"0","currentAverageValue":"16m"}}]'
       autoscaling.alpha.kubernetes.io/metrics: '[{"type":"External","external":{"metricName":"s0-prometheus-nginx_http_requests_total","metricSelector":{"matchLabels":{"scaledobject.keda.sh/name":"nginx-scaledobject"}},"targetAverageValue":"3"}}]'
       kubectl.kubernetes.io/last-applied-configuration: |
         {"apiVersion":"keda.sh/v1alpha1","kind":"ScaledObject","metadata":{"annotations":{},"labels":{"deploymentName":"nginx-deployment"},"name":"nginx-scaledobject","namespace":"default"},"spec":{"fallback":{"failureThreshold":3,"replicas":5},"maxReplicaCount":5,"minReplicaCount":1,"scaleTargetRef":{"name":"nginx-deployment"},"triggers":[{"metadata":{"metricName":"nginx_http_requests_total","query":"sum(rate(nginx_http_requests_total{app=\"nginx\"}[2m]))","serverAddress":"http://prometheus-server.monitoring.svc.cluster.local","threshold":"3"},"type":"prometheus"}]}}
     creationTimestamp: "2022-11-26T15:37:46Z"
     labels:
       app.kubernetes.io/managed-by: keda-operator
       app.kubernetes.io/name: keda-hpa-nginx-scaledobject
       app.kubernetes.io/part-of: nginx-scaledobject
       app.kubernetes.io/version: 2.8.1
       deploymentName: nginx-deployment
       scaledobject.keda.sh/name: nginx-scaledobject
     name: keda-hpa-nginx-scaledobject
     namespace: default
     ownerReferences:
     - apiVersion: keda.sh/v1alpha1
       blockOwnerDeletion: true
       controller: true
       kind: ScaledObject
       name: nginx-scaledobject
       uid: 38ffaf3a-8033-4d97-837a-a919e7f9eaec
     resourceVersion: "12875576"
     uid: 02e4603e-bd98-45b2-9c39-2e89f81393a2
   spec:
     maxReplicas: 5
     minReplicas: 1
     scaleTargetRef:
       apiVersion: apps/v1
       kind: Deployment
       name: nginx-deployment
   status:
     currentReplicas: 1
     desiredReplicas: 1
     lastScaleTime: "2022-12-03T07:40:28Z"metadata:
     annotations:
       autoscaling.alpha.kubernetes.io/conditions: '[{"type":"AbleToScale","status":"True","lastTransitionTime":"2022-11-26T15:38:01Z","reason":"ReadyForNewScale","message":"recommended
         size matches current size"},{"type":"ScalingActive","status":"True","lastTransitionTime":"2022-12-10T06:28:49Z","reason":"ValidMetricFound","message":"the
         HPA was able to successfully calculate a replica count from external metric
         s0-prometheus-nginx_http_requests_total(\u0026LabelSelector{MatchLabels:map[string]string{scaledobject.keda.sh/name:
         nginx-scaledobject,},MatchExpressions:[]LabelSelectorRequirement{},})"},{"type":"ScalingLimited","status":"False","lastTransitionTime":"2022-11-26T16:27:54Z","reason":"DesiredWithinRange","message":"the
         desired count is within the acceptable range"}]'
       autoscaling.alpha.kubernetes.io/current-metrics: '[{"type":"External","external":{"metricName":"s0-prometheus-nginx_http_requests_total","metricSelector":{"matchLabels":{"scaledobject.keda.sh/name":"nginx-scaledobject"}},"currentValue":"0","currentAverageValue":"16m"}}]'
       autoscaling.alpha.kubernetes.io/metrics: '[{"type":"External","external":{"metricName":"s0-prometheus-nginx_http_requests_total","metricSelector":{"matchLabels":{"scaledobject.keda.sh/name":"nginx-scaledobject"}},"targetAverageValue":"3"}}]'
       kubectl.kubernetes.io/last-applied-configuration: |
         {"apiVersion":"keda.sh/v1alpha1","kind":"ScaledObject","metadata":{"annotations":{},"labels":{"deploymentName":"nginx-deployment"},"name":"nginx-scaledobject","namespace":"default"},"spec":{"fallback":{"failureThreshold":3,"replicas":5},"maxReplicaCount":5,"minReplicaCount":1,"scaleTargetRef":{"name":"nginx-deployment"},"triggers":[{"metadata":{"metricName":"nginx_http_requests_total","query":"sum(rate(nginx_http_requests_total{app=\"nginx\"}[2m]))","serverAddress":"http://prometheus-server.monitoring.svc.cluster.local","threshold":"3"},"type":"prometheus"}]}}
     creationTimestamp: "2022-11-26T15:37:46Z"
     labels:
       app.kubernetes.io/managed-by: keda-operator
       app.kubernetes.io/name: keda-hpa-nginx-scaledobject
       app.kubernetes.io/part-of: nginx-scaledobject
       app.kubernetes.io/version: 2.8.1
       deploymentName: nginx-deployment
       scaledobject.keda.sh/name: nginx-scaledobject
     name: keda-hpa-nginx-scaledobject
     namespace: default
     ownerReferences:
     - apiVersion: keda.sh/v1alpha1
       blockOwnerDeletion: true
       controller: true
       kind: ScaledObject
       name: nginx-scaledobject
       uid: 38ffaf3a-8033-4d97-837a-a919e7f9eaec
     resourceVersion: "12875576"
     uid: 02e4603e-bd98-45b2-9c39-2e89f81393a2
   spec:
     maxReplicas: 5
     minReplicas: 1
     scaleTargetRef:
       apiVersion: apps/v1
       kind: Deployment
       name: nginx-deployment
   status:
     currentReplicas: 1
     desiredReplicas: 1
     lastScaleTime: "2022-12-03T07:40:28Z"
   
   $ kubectl describe hpa keda-hpa-nginx-scaledobject
   Name:                                                                keda-hpa-nginx-scaledobject
   Namespace:                                                           default
   Labels:                                                              app.kubernetes.io/managed-by=keda-operator
                                                                        app.kubernetes.io/name=keda-hpa-nginx-scaledobject
                                                                        app.kubernetes.io/part-of=nginx-scaledobject
                                                                        app.kubernetes.io/version=2.8.1
                                                                        deploymentName=nginx-deployment
                                                                        scaledobject.keda.sh/name=nginx-scaledobject
   Annotations:                                                         <none>
   CreationTimestamp:                                                   Sun, 27 Nov 2022 00:37:46 +0900
   Reference:                                                           Deployment/nginx-deployment
   Metrics:                                                             ( current / target )
     "s0-prometheus-nginx_http_requests_total" (target average value):  17m / 3
   Min replicas:                                                        1
   Max replicas:                                                        5
   Deployment pods:                                                     2 current / 2 desired
   Conditions:
     Type            Status  Reason               Message
     ----            ------  ------               -------
     AbleToScale     True    ScaleDownStabilized  recent recommendations were higher than current one, applying the highest recent recommendation
     ScalingActive   True    ValidMetricFound     the HPA was able to successfully calculate a replica count from external metric s0-prometheus-nginx_http_requests_total(&LabelSelector{MatchLabels:map[string]string{scaledobject.keda.sh/name: nginx-scaledobject,},MatchExpressions:[]LabelSelectorRequirement{},})
     ScalingLimited  False   DesiredWithinRange   the desired count is within the acceptable range
   Events:           <none>
   

   ScaledObject

   $ kubectl get scaledobject
   NAME                 SCALETARGETKIND      SCALETARGETNAME    MIN   MAX   TRIGGERS     AUTHENTICATION   READY   ACTIVE   FALLBACK   AGE
   nginx-scaledobject   apps/v1.Deployment   nginx-deployment   1     5     prometheus                    True    True     False      2m58s
   
   $ kubectl describe scaledobject nginx-scaledobject
   Name:         nginx-scaledobject
   Namespace:    default
   Labels:       deploymentName=nginx-deployment
                 scaledobject.keda.sh/name=nginx-scaledobject
   Annotations:  <none>
   API Version:  keda.sh/v1alpha1
   Kind:         ScaledObject
   Metadata:
     Creation Timestamp:  2022-11-26T15:37:46Z
     Finalizers:
       finalizer.keda.sh
     Generation:  1
     Managed Fields:
       API Version:  keda.sh/v1alpha1
       Fields Type:  FieldsV1
       fieldsV1:
         f:metadata:
           f:finalizers:
             .:
             v:"finalizer.keda.sh":
           f:labels:
             f:scaledobject.keda.sh/name:
       Manager:      keda
       Operation:    Update
       Time:         2022-11-26T15:37:46Z
       API Version:  keda.sh/v1alpha1
       Fields Type:  FieldsV1
       fieldsV1:
         f:metadata:
           f:annotations:
             .:
             f:kubectl.kubernetes.io/last-applied-configuration:
           f:labels:
             .:
             f:deploymentName:
         f:spec:
           .:
           f:fallback:
             .:
             f:failureThreshold:
             f:replicas:
           f:maxReplicaCount:
           f:minReplicaCount:
           f:scaleTargetRef:
             .:
             f:name:
           f:triggers:
       Manager:      kubectl-client-side-apply
       Operation:    Update
       Time:         2022-11-26T15:37:46Z
       API Version:  keda.sh/v1alpha1
       Fields Type:  FieldsV1
       fieldsV1:
         f:status:
           f:health:
             .:
             f:s0-prometheus-nginx_http_requests_total:
               .:
               f:numberOfFailures:
               f:status:
       Manager:      keda-adapter
       Operation:    Update
       Subresource:  status
       Time:         2022-11-26T15:38:01Z
       API Version:  keda.sh/v1alpha1
       Fields Type:  FieldsV1
       fieldsV1:
         f:status:
           .:
           f:conditions:
           f:externalMetricNames:
           f:hpaName:
           f:lastActiveTime:
           f:originalReplicaCount:
           f:scaleTargetGVKR:
             .:
             f:group:
             f:kind:
             f:resource:
             f:version:
           f:scaleTargetKind:
       Manager:         keda
       Operation:       Update
       Subresource:     status
       Time:            2022-11-26T15:39:46Z
     Resource Version:  10027225
     UID:               38ffaf3a-8033-4d97-837a-a919e7f9eaec
   Spec:
     Fallback:
       Failure Threshold:  3
       Replicas:           5
     Max Replica Count:    5
     Min Replica Count:    1
     Scale Target Ref:
       Name:  nginx-deployment
     Triggers:
       Metadata:
         Metric Name:     nginx_http_requests_total
         Query:           sum(rate(nginx_http_requests_total{app="nginx"}[2m]))
         Server Address:  http://prometheus-server.monitoring.svc.cluster.local
         Threshold:       3
       Type:              prometheus
   Status:
     Conditions:
       Message:  ScaledObject is defined correctly and is ready for scaling
       Reason:   ScaledObjectReady
       Status:   True
       Type:     Ready
       Message:  Scaling is performed because triggers are active
       Reason:   ScalerActive
       Status:   True
       Type:     Active
       Message:  No fallbacks are active on this scaled object
       Reason:   NoFallbackFound
       Status:   False
       Type:     Fallback
     External Metric Names:
       s0-prometheus-nginx_http_requests_total
     Health:
       s0-prometheus-nginx_http_requests_total:
         Number Of Failures:  0
         Status:              Happy
     Hpa Name:                keda-hpa-nginx-scaledobject
     Last Active Time:        2022-11-26T15:41:16Z
     Original Replica Count:  2
     Scale Target GVKR:
       Group:            apps
       Kind:             Deployment
       Resource:         deployments
       Version:          v1
     Scale Target Kind:  apps/v1.Deployment
   Events:
     Type    Reason              Age    From           Message
     ----    ------              ----   ----           -------
     Normal  KEDAScalersStarted  3m54s  keda-operator  Started scalers watch
     Normal  ScaledObjectReady   3m54s  keda-operator  ScaledObject is ready for scaling
   

5. 負荷をかける

   • nginxコンテナにattachして http://localhost/nginx_status に対してのアクセスを増やしてみる

6. scaleout/scalein を確認

   $ while true; do date ; kubectl describe hpa keda-hpa-nginx-scaledobject | grep -A 30 "^Metrics:" ; echo ; echo ; sleep 1 ; done
   
   snip...
   
   2022年 11月27日 日曜日 02時06分09秒 JST
   Metrics:                                                             ( current / target )
     "s0-prometheus-nginx_http_requests_total" (target average value):  33m / 3
   Min replicas:                                                        1
   Max replicas:                                                        5
   Deployment pods:                                                     1 current / 1 desired
   Conditions:
     Type            Status  Reason              Message
     ----            ------  ------              -------
     AbleToScale     True    ReadyForNewScale    recommended size matches current size
     ScalingActive   True    ValidMetricFound    the HPA was able to successfully calculate a replica count from external metric s0-prometheus-nginx_http_requests_total(&LabelSelector{MatchLabels:map[string]string{scaledobject.keda.sh/name: nginx-scaledobject,},MatchExpressions:[]LabelSelectorRequirement{},})
     ScalingLimited  False   DesiredWithinRange  the desired count is within the acceptable range
   Events:
     Type    Reason             Age                From                       Message
     ----    ------             ----               ----                       -------
     Normal  SuccessfulRescale  59m                horizontal-pod-autoscaler  New size: 3; reason: external metric s0-prometheus-nginx_http_requests_total(&LabelSelector{MatchLabels:map[string]string{scaledobject.keda.sh/name: nginx-scaledobject,},MatchExpressions:[]LabelSelectorRequirement{},}) above target
     Normal  SuccessfulRescale  54m                horizontal-pod-autoscaler  New size: 4; reason: external metric s0-prometheus-nginx_http_requests_total(&LabelSelector{MatchLabels:map[string]string{scaledobject.keda.sh/name: nginx-scaledobject,},MatchExpressions:[]LabelSelectorRequirement{},}) above target
     Normal  SuccessfulRescale  51m                horizontal-pod-autoscaler  New size: 5; reason: external metric s0-prometheus-nginx_http_requests_total(&LabelSelector{MatchLabels:map[string]string{scaledobject.keda.sh/name: nginx-scaledobject,},MatchExpressions:[]LabelSelectorRequirement{},}) above target
     Normal  SuccessfulRescale  37m                horizontal-pod-autoscaler  New size: 3; reason: All metrics below target
     Normal  SuccessfulRescale  5m45s              horizontal-pod-autoscaler  New size: 2; reason: All metrics below target
     Normal  SuccessfulRescale  42s (x2 over 83m)  horizontal-pod-autoscaler  New size: 1; reason: All metrics below target
   

7. grafanaで確認

   • green: sum(rate(nginx_http_requests_total[10m]))
   • yellow: sum(irate(nginx_http_requests_total{app="nginx"}[10m]))
   • blue: kube_deployment_status_replicas{deployment="nginx-deployment"}