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前言

Metrics Server是Kubernetes内置自动伸缩管道的一个可伸缩、高效的容器资源度量来源。

Metrics Server从Kubelets收集资源指标，并通过Metrics API将它们暴露在Kubernetes apiserver中，供水平Pod Autoscaler和垂直Pod Autoscaler使用。kubectl top还可以访问Metrics API，这使得调试自动伸缩管道变得更容易。

Metrics Server不是用于非自动伸缩的目的。例如，不要将其用于将指标转发给监视解决方案，或者作为监视解决方案指标的来源。在这种情况下，请直接从Kubelet /metrics/resource端点收集度量。

Metrics Server提供

• 在大多数集群上工作的单个部署
• 快速自动缩放，每15秒收集一次指标。
• 资源效率，为集群中的每个节点使用1毫秒的CPU内核和2 MB的内存。
• 可扩展支持多达5000个节点群集。

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提示：以下是本篇文章正文内容，下面案例可供参考

一、Metrics Server 与 kubenetes版本

Metrics Server	Metrics API group/version	Supported Kubernetes version
0.6x	metrics.k8s.io/v1beta1	*1.19+
0.5x	metrics.k8s.io/v1beta1	*1.8+
0.4x	metrics.k8s.io/v1beta1	*1.8+
0.3x	metrics.k8s.io/v1beta1	1.8-1.21

更多的详细资料，请前往github查看。

二、Metrics Server 下载方式

• github：https://github.com/kubernetes-sigs/metrics-server

三、k8s集群安装部署metrics

本次我们安装的是metrics0.5.0版本
下载地址：https://github.com/kubernetes-sigs/metrics-server/releases
docker镜像地址：docker pull cnskylee/metrics-server:v0.5.0

1. 在k8s集群里面下载metrics-server镜像，保证每一台主机都能都访问到镜像

#下载镜像
docker pull cnskylee/metrics-server:v0.5.0
#修改标签
docker tag cnskylee/metrics-server:v0.5.0 k8s.gcr.io/metrics-server/metrics-server:v0.5.0

2. 创建components-v0.5.0.yaml文件，并将下面的脚本copy到文件中

apiVersion: v1
kind: ServiceAccount
metadata:labels:k8s-app: metrics-servername: metrics-servernamespace: kube-system
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRole
metadata:labels:k8s-app: metrics-serverrbac.authorization.k8s.io/aggregate-to-admin: "true"rbac.authorization.k8s.io/aggregate-to-edit: "true"rbac.authorization.k8s.io/aggregate-to-view: "true"name: system:aggregated-metrics-reader
rules:1. apiGroups:2. metrics.k8s.ioresources:3. pods4. nodesverbs:5. get6. list7. watch
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRole
metadata:labels:k8s-app: metrics-servername: system:metrics-server
rules:8. apiGroups:9. ""resources:10. pods11. nodes12. nodes/stats13. namespaces14. configmapsverbs:15. get16. list17. watch
---
apiVersion: rbac.authorization.k8s.io/v1
kind: RoleBinding
metadata:labels:k8s-app: metrics-servername: metrics-server-auth-readernamespace: kube-system
roleRef:apiGroup: rbac.authorization.k8s.iokind: Rolename: extension-apiserver-authentication-reader
subjects:18. kind: ServiceAccountname: metrics-servernamespace: kube-system
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:labels:k8s-app: metrics-servername: metrics-server:system:auth-delegator
roleRef:apiGroup: rbac.authorization.k8s.iokind: ClusterRolename: system:auth-delegator
subjects:19. kind: ServiceAccountname: metrics-servernamespace: kube-system
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:labels:k8s-app: metrics-servername: system:metrics-server
roleRef:apiGroup: rbac.authorization.k8s.iokind: ClusterRolename: system:metrics-server
subjects:20. kind: ServiceAccountname: metrics-servernamespace: kube-system
---
apiVersion: v1
kind: Service
metadata:labels:k8s-app: metrics-servername: metrics-servernamespace: kube-system
spec:ports:21. name: httpsport: 443protocol: TCPtargetPort: httpsselector:k8s-app: metrics-server
---
apiVersion: apps/v1
kind: Deployment
metadata:labels:k8s-app: metrics-servername: metrics-servernamespace: kube-system
spec:selector:matchLabels:k8s-app: metrics-serverstrategy:rollingUpdate:maxUnavailable: 0template:metadata:labels:k8s-app: metrics-serverspec:containers:- args:- --cert-dir=/tmp- --secure-port=443- --kubelet-preferred-address-types=InternalIP,ExternalIP,Hostname- --kubelet-use-node-status-port- --metric-resolution=15s- --kubelet-insecure-tlsimage: k8s.gcr.io/metrics-server/metrics-server:v0.5.0imagePullPolicy: IfNotPresentlivenessProbe:failureThreshold: 3httpGet:path: /livezport: httpsscheme: HTTPSperiodSeconds: 10name: metrics-serverports:- containerPort: 443name: httpsprotocol: TCPreadinessProbe:failureThreshold: 3httpGet:path: /readyzport: httpsscheme: HTTPSinitialDelaySeconds: 20periodSeconds: 10resources:requests:cpu: 100mmemory: 200MisecurityContext:readOnlyRootFilesystem: truerunAsNonRoot: truerunAsUser: 1000volumeMounts:- mountPath: /tmpname: tmp-dirnodeSelector:kubernetes.io/os: linuxpriorityClassName: system-cluster-criticalserviceAccountName: metrics-servervolumes:- emptyDir: {}name: tmp-dir
---
apiVersion: apiregistration.k8s.io/v1
kind: APIService
metadata:labels:k8s-app: metrics-servername: v1beta1.metrics.k8s.io
spec:group: metrics.k8s.iogroupPriorityMinimum: 100insecureSkipTLSVerify: trueservice:name: metrics-servernamespace: kube-systemversion: v1beta1versionPriority: 100

3. 执行安装

kubectl apply -f ./components-v0.5.0.yaml

4.查看metrics-server的pod运行状态

kubectl get pods -n kube-system| egrep 'NAME|metrics-server'

5.测试kubectl top命令的使用

kubectl top pods -n kube-system