Kubernetes AutoScaler 未扩展，HPA 显示目标 <unknown>

Question

我是 kubernetes 的新手，对 docker 不是很了解。

我一直在研究这个例子，但我被自动缩放器困住了（它似乎无法缩放）。

我正在处理这里的示例 https://kubernetes.io/docs/tasks/run-application/horizontal-pod-autoscale-walkthrough/#step-one-run--expose-php-apache-server

您会在底部找到构建

kubectl create -f https://k8s.io/docs/tasks/run-application/hpa-php-apache.yaml

看起来像这样

apiVersion: autoscaling/v1
kind: HorizontalPodAutoscaler
metadata:
  name: php-apache
  namespace: default
spec:
  scaleTargetRef:
    apiVersion: apps/v1
    kind: Deployment
    name: php-apache
  minReplicas: 1
  maxReplicas: 10
  targetCPUUtilizationPercentage: 50

kubectl get hba 显示

NAME         REFERENCE               TARGETS         MINPODS   MAXPODS   REPLICAS   AGE
php-apache   Deployment/php-apache   <unknown>/50%   1         10        0          7s

<unknown> 部分中的线索。

然后kubectl describe hba显示

Name:                                                  php-apache
Namespace:                                             default
Labels:                                                <none>
Annotations:                                           <none>
CreationTimestamp:                                     Sat, 14 Apr 2018 23:05:05 +0100
Reference:                                             Deployment/php-apache
Metrics:                                               ( current / target )
  resource cpu on pods  (as a percentage of request):  <unknown> / 50%
Min replicas:                                          1
Max replicas:                                          10
Conditions:
  Type         Status  Reason          Message
  ----         ------  ------          -------
  AbleToScale  False   FailedGetScale  the HPA controller was unable to get the target's current scale: deployments/scale.extensions "php-apache" not found
Events:
  Type     Reason          Age                From                       Message
  ----     ------          ----               ----                       -------
  Warning  FailedGetScale  12s (x14 over 6m)  horizontal-pod-autoscaler  deployments/scale.extensions "php-apache" not found

然后我手动添加它...

kubectl run php-apache --image=k8s.gcr.io/hpa-example --requests=cpu=200m --expose --port=80

然后如果我再次运行 kubectl describe hpa 我得到这个错误..

Name:                                                  php-apache
Namespace:                                             default
Labels:                                                <none>
Annotations:                                           <none>
CreationTimestamp:                                     Sat, 14 Apr 2018 23:05:05 +0100
Reference:                                             Deployment/php-apache
Metrics:                                               ( current / target )
  resource cpu on pods  (as a percentage of request):  <unknown> / 50%
Min replicas:                                          1
Max replicas:                                          10
Conditions:
  Type           Status  Reason                   Message
  ----           ------  ------                   -------
  AbleToScale    True    SucceededGetScale        the HPA controller was able to get the target's current scale
  ScalingActive  False   FailedGetResourceMetric  the HPA was unable to compute the replica count: unable to get metrics for resource cpu: unable to fetch metrics from API: the server could not find the requested resource (get pods.metrics.k8s.io)
Events:
  Type     Reason                        Age                From                       Message
  ----     ------                        ----               ----                       -------
  Warning  FailedGetScale                1m (x21 over 11m)  horizontal-pod-autoscaler  deployments/scale.extensions "php-apache" not found
  Warning  FailedGetResourceMetric       8s (x2 over 38s)   horizontal-pod-autoscaler  unable to get metrics for resource cpu: unable to fetch metrics from API: the server could not find the requested resource (get pods.metrics.k8s.io)
  Warning  FailedComputeMetricsReplicas  8s (x2 over 38s)   horizontal-pod-autoscaler  failed to get cpu utilization: unable to get metrics for resource cpu: unable to fetch metrics from API: the server could not find the requested resource (get pods.metrics.k8s.io)

Answer 1

由于 Heapster 在 kubernetes 的更高版本 (v 1.13) 中被弃用，您也可以使用 metrics-server 公开您的指标，请查看以下答案以了解设置 HPA 的分步说明：

Answer 2

直接回答问题，如果你设置了HPA资源并使用了metrics server，并且运行进入这个错误。

这个错误意味着在你的pods中，可能有多个容器，其中一个或两个容器没有定义资源请求：

Resources:
     requests:
       cpu: <this is missing! Add it>

检查所有容器是否都定义了资源请求。

要直接添加编辑和添加资源，请使用 kubectl edit <resource>

如果您使用 helm，即使带有 force 标志，Kubernetes 也可能不允许您更新。

请注意，如果您尚未设置 PodDisruptionBudgets，这可能会导致停机，因此请在您运行您的编辑

之前设置这些

Answer 3

确保 HPA 正常运行需要两件事

指标服务器是运行
可扩展资源 (Pod/Statefulset) 定义了 CPU/Memory 资源请求和限制。（仅在cpu/mem范围内讨论，其他自定义指标可以启用HPA使用）

检查指标服务器是否运行 -

kubectl get po -n kube-system | grep metric

如果您 none 已列出，则您的指标服务器还没有运行。参考 Readme 并安装度量服务器。添加 CPU 限制不会有帮助，除非您的指标服务是运行.

现在请确保您在 Pod 或可扩展目标中定义了资源请求和限制。

 resources:
  requests:
    memory: "64Mi"
    cpu: "250m"
  limits:
    memory: "128Mi"
    cpu: "250m"

此外，只有当您根据 cpu/mem数据进行扩展时，指标服务器才会有用。

Kubernetes AutoScaler 未扩展，HPA 显示目标 <unknown>

Kubernetes AutoScaler Not Scaling, HPA shows target <unknown>

autoscaling

kubernetes