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kubernetes - 根据每个 pod 的活动连接数扩展 GKE pod

问题描述

我有一个使用目标 CPU 利用率指标的带有 HPA 的正在运行的 GKE 集群。这没关系，但 CPU 利用率并不是我们的最佳扩展指标。分析表明，活动连接数是一般平台负载的一个很好的指标，因此，我们希望将其作为我们的主要扩展指标。

为此，我为我们使用的 NGINX 入口启用了自定义指标。从这里我们可以看到活动连接数、请求率等。

这是使用 NGINX 自定义指标的 HPA 规范：

apiVersion: autoscaling/v2beta1
kind: HorizontalPodAutoscaler
metadata:
  name: hpa-uat-active-connections
  namespace: default
spec:
  minReplicas: 3
  maxReplicas: 6
  metrics:
    - type: Pods
      pods:
        metricName: custom.googleapis.com|nginx-ingress-controller|nginx_ingress_controller_nginx_process_connections
        selector: 
          matchLabels:
            metric.labels.state: active
            resource.labels.cluster_name: "[redacted]"
        targetAverageValue: 5
  scaleTargetRef:
    apiVersion: apps/v1
    kind: Deployment
    name: "[redacted]"

然而，虽然这个规范确实部署得很好，但我总是从 HPA 得到这个输出：

NAME                         REFERENCE                                 TARGETS       MINPODS   MAXPODS   REPLICAS   AGE
hpa-uat-active-connections   Deployment/[redacted]                     <unknown>/5   3         6         3          31s

简而言之，目标值是“未知的”，到目前为止我无法理解/解决原因。自定义指标确实存在：

kubectl get --raw "/apis/external.metrics.k8s.io/v1beta1/namespaces/default/custom.googleapis.com|nginx-ingress-controller|ng​​inx_ingress_controller_nginx_process_connections?labelSelector=metric.labels.state%3Dactive,resource.labels .cluster_name%3D[编辑]" | jq

这使：

{
  "kind": "ExternalMetricValueList",
  "apiVersion": "external.metrics.k8s.io/v1beta1",
  "metadata": {
    "selfLink": "/apis/external.metrics.k8s.io/v1beta1/namespaces/default/custom.googleapis.com%7Cnginx-ingress-controller%7Cnginx_ingress_controller_nginx_process_connections"
  },
  "items": [
    {
      "metricName": "custom.googleapis.com|nginx-ingress-controller|nginx_ingress_controller_nginx_process_connections",
      "metricLabels": {
        "metric.labels.controller_class": "nginx",
        "metric.labels.controller_namespace": "ingress-nginx",
        "metric.labels.controller_pod": "nginx-ingress-controller-54f84b8dff-sml6l",
        "metric.labels.state": "active",
        "resource.labels.cluster_name": "[redacted]",
        "resource.labels.container_name": "",
        "resource.labels.instance_id": "[redacted]-eac4b327-stqn",
        "resource.labels.namespace_id": "ingress-nginx",
        "resource.labels.pod_id": "nginx-ingress-controller-54f84b8dff-sml6l",
        "resource.labels.project_id": "[redacted],
        "resource.labels.zone": "[redacted]",
        "resource.type": "gke_container"
      },
      "timestamp": "2019-12-30T14:11:01Z",
      "value": "1"
    }
  ]
}

所以我有两个问题，真的：

  1. （主要的）：我在这里做错了什么导致 HPA 无法读取指标？
  2. 这是尝试扩展到多个 pod 上的平均活动连接负载的正确方法吗？

非常感谢，本

编辑 1

kubectl 得到所有

NAME                                                READY   STATUS    RESTARTS   AGE
pod/[redacted]-deployment-7f5fbc9ddf-l9tqk          1/1     Running   0          34h
pod/[redacted]-uat-deployment-7f5fbc9ddf-pbcns      1/1     Running   0          34h
pod/[redacted]-uat-deployment-7f5fbc9ddf-tjfrm      1/1     Running   0          34h

NAME                                TYPE        CLUSTER-IP     EXTERNAL-IP   PORT(S)                      AGE
service/[redacted]-webapp-service   NodePort    [redacted]     <none>        [redacted]                   57d
service/kubernetes                  ClusterIP   [redacted]     <none>        [redacted]                   57d

NAME                                           READY   UP-TO-DATE   AVAILABLE   AGE
deployment.apps/[redacted]-uat-deployment      3/3     3            3           57d

NAME                                                      DESIRED   CURRENT   READY   AGE
replicaset.apps/[redacted]-uat-deployment-54b6bd5f9c      0         0         0       12d
replicaset.apps/[redacted]-uat-deployment-574c778cc9      0         0         0       35h
replicaset.apps/[redacted]-uat-deployment-66546bf76b      0         0         0       11d
replicaset.apps/[redacted]-uat-deployment-698dfbb6c4      0         0         0       4d
replicaset.apps/[redacted]-uat-deployment-69b5c79d54      0         0         0       6d17h
replicaset.apps/[redacted]-uat-deployment-6f67ff6599      0         0         0       10d
replicaset.apps/[redacted]-uat-deployment-777bfdbb9d      0         0         0       3d23h
replicaset.apps/[redacted]-uat-deployment-7f5fbc9ddf      3         3         3       34h
replicaset.apps/[redacted]-uat-deployment-9585454ff       0         0         0       6d21h
replicaset.apps/[redacted]-uat-deployment-97cbcfc6        0         0         0       17d
replicaset.apps/[redacted]-uat-deployment-c776f648d       0         0         0       10d

NAME                                                               REFERENCE                                 TARGETS   MINPODS   MAXPODS   REPLICAS   AGE
horizontalpodautoscaler.autoscaling/[redacted]-uat-deployment      Deployment/[redacted]-uat-deployment      4%/80%    3         6         3          9h

标签： kuberneteshorizontal-scaling

解决方案

好的，我设法通过查找 HPA 的架构来解决这个问题（https://docs.okd.io/latest/rest_api/apis-autoscaling/v2beta1.Horizo​​ntalPodAutoscaler.html）。

简而言之，我使用了错误的度量类型（如上您可以看到我使用的是“Pods”，但我应该使用“External”）。

正确的 HPA 规范是：

apiVersion: autoscaling/v2beta1
kind: HorizontalPodAutoscaler
metadata:
  name: hpa-uat-active-connections
  namespace: default
spec:
  minReplicas: 3
  maxReplicas: 6
  metrics:
    - type: External
      external:
        metricName: custom.googleapis.com|nginx-ingress-controller|nginx_ingress_controller_nginx_process_connections
        metricSelector: 
          matchLabels:
            metric.labels.state: active
            resource.labels.cluster_name: [redacted]
        targetAverageValue: 5
  scaleTargetRef:
    apiVersion: apps/v1
    kind: Deployment
    name: [redacted]

一旦我这样做了，事情马上就奏效了：

NAME                         REFERENCE                                 TARGETS        MINPODS   MAXPODS   REPLICAS   AGE
hpa-uat-active-connections   Deployment/bustle-webapp-uat-deployment   334m/5 (avg)   3         6         3          30s

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