本文章视频教程地址：https://www.bilibili.com/video/BV1TdxkedE1K

前言

笔者之前写过一篇文章关于在Kubernetes上安装 Prometheus 和 Grafana 监控去查看Kubernetes各个节点的资源占用率，文章地址：https://blog.csdn.net/m0_51510236/article/details/132601350

但是有一个更方便的方法，就是直接使用 kubectl 命令查看各个节点的资源使用情况。具体的命令如下：

kubectl top nodes

但默认的执行结果是：

原因是你没有安装 metrics-server，metrics-server 的github地址为：https://github.com/kubernetes-sigs/metrics-server。

安装 metrics-server

根据代码仓库的Releases列表显示，最新版本为 v0.7.2：

其中 v0.7.2 这个版本需要你的 Kubernetes 集群的版本为 1.19 或更高：

官方给出的安装命令为：

kubectl apply -f https://github.com/kubernetes-sigs/metrics-server/releases/latest/download/components.yaml

⚠️不要执行这个命令来安装 metrics-server，需要先将这个文件保存下来，并修改一些内容。可执行下面这行命令修改：

curl -LO https://github.com/kubernetes-sigs/metrics-server/releases/latest/download/components.yaml

如果你是自己搭建的Kubernetes集群，你需要在 yaml 文件的 Deployment 当中添加这么一个执行参数：--kubelet-insecure-tls。如图加在约 137 行位置：

还有在 image 的配置中，默认镜像是 registry.k8s.io/metrics-server/metrics-server:v0.7.2 ，是在谷歌上拉取的，阿里云也有这个镜像，需要改成阿里云上的镜像： registry.aliyuncs.com/google_containers/metrics-server:v0.7.2，如图：

然后需要将 Deployment.spec.template.spec.hostNetwork 改为 false，如图：

修改好后的文件内容：

apiVersion: v1
kind: ServiceAccount
metadata:
  labels:
    k8s-app: metrics-server
  name: metrics-server
  namespace: kube-system
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRole
metadata:
  labels:
    k8s-app: metrics-server
    rbac.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:
- apiGroups:
  - metrics.k8s.io
  resources:
  - pods
  - nodes
  verbs:
  - get
  - list
  - watch
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRole
metadata:
  labels:
    k8s-app: metrics-server
  name: system:metrics-server
rules:
- apiGroups:
  - ""
  resources:
  - nodes/metrics
  verbs:
  - get
- apiGroups:
  - ""
  resources:
  - pods
  - nodes
  verbs:
  - get
  - list
  - watch
---
apiVersion: rbac.authorization.k8s.io/v1
kind: RoleBinding
metadata:
  labels:
    k8s-app: metrics-server
  name: metrics-server-auth-reader
  namespace: kube-system
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: Role
  name: extension-apiserver-authentication-reader
subjects:
- kind: ServiceAccount
  name: metrics-server
  namespace: kube-system
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:
  labels:
    k8s-app: metrics-server
  name: metrics-server:system:auth-delegator
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: system:auth-delegator
subjects:
- kind: ServiceAccount
  name: metrics-server
  namespace: kube-system
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:
  labels:
    k8s-app: metrics-server
  name: system:metrics-server
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: system:metrics-server
subjects:
- kind: ServiceAccount
  name: metrics-server
  namespace: kube-system
---
apiVersion: v1
kind: Service
metadata:
  labels:
    k8s-app: metrics-server
  name: metrics-server
  namespace: kube-system
spec:
  ports:
  - name: https
    port: 443
    protocol: TCP
    targetPort: https
  selector:
    k8s-app: metrics-server
---
apiVersion: apps/v1
kind: Deployment
metadata:
  labels:
    k8s-app: metrics-server
  name: metrics-server
  namespace: kube-system
spec:
  selector:
    matchLabels:
      k8s-app: metrics-server
  strategy:
    rollingUpdate:
      maxUnavailable: 0
  template:
    metadata:
      labels:
        k8s-app: metrics-server
    spec:
      containers:
      - args:
        - --cert-dir=/tmp
        - --secure-port=10250
        - --kubelet-insecure-tls
        - --kubelet-preferred-address-types=InternalIP,ExternalIP,Hostname
        - --kubelet-use-node-status-port
        - --metric-resolution=15s
        image: registry.aliyuncs.com/google_containers/metrics-server:v0.7.2
        imagePullPolicy: IfNotPresent
        livenessProbe:
          failureThreshold: 3
          httpGet:
            path: /livez
            port: https
            scheme: HTTPS
          periodSeconds: 10
        name: metrics-server
        ports:
        - containerPort: 10250
          name: https
          protocol: TCP
        readinessProbe:
          failureThreshold: 3
          httpGet:
            path: /readyz
            port: https
            scheme: HTTPS
          initialDelaySeconds: 20
          periodSeconds: 10
        resources:
          requests:
            cpu: 100m
            memory: 200Mi
        securityContext:
          allowPrivilegeEscalation: false
          capabilities:
            drop:
            - ALL
          readOnlyRootFilesystem: true
          runAsNonRoot: true
          runAsUser: 1000
          seccompProfile:
            type: RuntimeDefault
        volumeMounts:
        - mountPath: /tmp
          name: tmp-dir
      hostNetwork: false
      nodeSelector:
        kubernetes.io/os: linux
      priorityClassName: system-cluster-critical
      serviceAccountName: metrics-server
      volumes:
      - emptyDir: {
   }
        name: tmp-dir
---
apiVersion: apiregistration.k8s.io/v1
kind: APIService
metadata:
  labels:
    k8s-app: metrics-server
  name: v1beta1.metrics.k8s.io
spec:
  group: metrics.k8s.io
  groupPriorityMinimum: 100
  insecureSkipTLSVerify: true
  service:
    name: metrics-server
    namespace: kube-system
  version: v1beta1
  versionPriority: 100

然后执行该文件就可以安装成功了，同样我也修改好了这个文件并提交至github，可以啥也不改直接执行下面这样一行命令进行安装：

kubectl apply -f https://raw.githubusercontent.com/xiaohh-me/kubernetes-yaml/main/plugin/metrics-server/components-v0.7.2.yaml

执行完成如图：

可以执行这行命令查看是否安装成功：

kubectl get pod -n kube-system -o wide

成功运行如图：

使用 kubectl 查看 cpu 和内存占用率

接下来就可以执行这行命令查看 cpu 和内存占用率：

kubectl top nodes

执行结果如图：