Kubernetes 指标服务器不提供所有指标或扩展 HPA

Posted 2023-03-04

【中文标题】Kubernetes 指标服务器不提供所有指标或扩展 HPA

【英文标题】：Kubernetes metrics-server doesn't provide all metrics or scale HPA

【发布时间】：2021-02-17 10:20:30

【问题描述】：

按照此处https://kubernetes.io/docs/tasks/run-application/horizontal-pod-autoscale-walkthrough/#autoscaling-on-metrics-not-related-to-kubernetes-objects 的示例，我创建了已安装的metrics-server 并对其进行了如下修改：

    spec:
      containers:
      - command:
        - metrics-server
        - --secure-port=8443
        - --kubelet-insecure-tls=true
        - --kubelet-preferred-address-types=InternalIP,ExternalIP,Hostname
        image: docker.io/bitnami/metrics-server:0.3.7-debian-10-r89
        imagePullPolicy: IfNotPresent
        name: metrics-server
        ports:
        - containerPort: 8443
          name: https
          protocol: TCP
        resources: 

查询时会列出我的节点：

kubectl get --raw "/apis/metrics.k8s.io/v1beta1/nodes"
"kind":"NodeMetricsList","apiVersion":"metrics.k8s.io/v1beta1","metadata":"selfLink":"/apis/metrics.k8s.io/v1beta1/nodes","items":["metadata":"name":"eo-test-metrics-35lks","selfLink":"/apis/metrics.k8s.io/v1beta1/nodes/eo-test-metrics-35lks","creationTimestamp":"2020-11-04T04:05:58Z","timestamp":"2020-11-04T04:05:28Z","window":"30s","usage":"cpu":"770120208n","memory":"934476Ki","metadata":"name":"eo-test-metrics-35lkp","selfLink":"/apis/metrics.k8s.io/v1beta1/nodes/eo-test-metrics-35lkp","creationTimestamp":"2020-11-04T04:05:58Z","timestamp":"2020-11-04T04:05:25Z","window":"30s","usage":"cpu":"483763591n","memory":"850756Ki"]

但是，HPA 目标仍然“未知”：

kubectl get hpa
NAME REFERENCE TARGETS MINPODS MAXPODS REPLICAS AGE
php-apache Deployment/php-apache <unknown>/50% 1 10 1 31m

运行***节点有效，但*** pod 无效

kubectl top nodes
NAME                    CPU(cores)   CPU%   MEMORY(bytes)   MEMORY%
eo-test-metrics-35lkp   93m          4%     934Mi           30%
eo-test-metrics-35lks   166m         8%     1053Mi          33%

Top pods 返回错误error: Metrics not available:

 kubectl top pods
W1104 11:19:27.854485   62798 top_pod.go:266] Metrics not available for pod default/php-apache-d4cf67d68-blt2c, age: 13h1m51.854463s
error: Metrics not available for pod default/php-apache-d4cf67d68-blt2c, age: 13h1m51.854463s

这是在 Kubernetes 服务器版本 v1.19.3 和指标服务器版本 0.3.6 上

来自度量服务器的日志

E1104 21:21:56.496129       1 reststorage.go:160] unable to fetch pod metrics for pod default/php-apache-d4cf67d68-blt2c: no metrics known for pod
E1104 21:22:10.945091       1 reststorage.go:160] unable to fetch pod metrics for pod default/php-apache-d4cf67d68-blt2c: no metrics known for pod
E1104 21:22:26.496814       1 reststorage.go:160] unable to fetch pod metrics for pod default/php-apache-d4cf67d68-blt2c: no metrics known for pod

【参考方案1】：

当 Docker 19.03 用于 Kubernetes 版本 1.19 时，与此上游问题相关的问题已解决：https://github.com/kubernetes/kubernetes/issues/94281

【参考方案2】：

使用此版本的指标服务器

git clone https://github.com/kodekloudhub/kubernetes-metrics-server
kubectl apply -f kubernetes-metrics-server

然后按照this link中提到的相同说明进行操作

它会随着负载的增加而增加 pod 的数量

但是我注意到自动缩放器不会在负载停止时缩减部署。可能需要一些时间才能再次缩小规模

注意：此版本的指标服务器只能在开发或学习环境中使用。

我使用Katakoda environment 来测试答案。