Metrics Server collects resource metrics from Kubelet and exposes them to API server through Metric API. It’s a great tools to monitor system resources usage.

To deploy, use the following config with modification as below

apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  annotations:
    deployment.kubernetes.io/revision: "2"
  creationTimestamp: "2020-07-07T13:15:40Z"
  generation: 2
  labels:
    k8s-app: metrics-server
  name: metrics-server
  namespace: kube-system
  resourceVersion: "273400"
  selfLink: /apis/extensions/v1beta1/namespaces/kube-system/deployments/metrics-server
  uid: f4682170-c053-11ea-838e-000c29c98773
spec:
  progressDeadlineSeconds: 600
  replicas: 1
  revisionHistoryLimit: 10
  selector:
    matchLabels:
      k8s-app: metrics-server
  strategy:
    rollingUpdate:
      maxSurge: 25%
      maxUnavailable: 25%
    type: RollingUpdate
  template:
    metadata:
      creationTimestamp: null
      labels:
        k8s-app: metrics-server
      name: metrics-server
    spec:
      containers:
      - args:
        - --cert-dir=/tmp
        - --secure-port=4443
        ***- --kubelet-insecure-tls***
        ***- --kubelet-preferred-address-types=InternalIP,ExternalIP,Hostname***
        image: k8s.gcr.io/metrics-server-amd64:v0.3.6
        imagePullPolicy: IfNotPresent
        name: metrics-server
        ports:
        - containerPort: 4443
          hostPort: 4443
          name: main-port
          protocol: TCP
        resources: {}
        securityContext:
          procMount: Default
          readOnlyRootFilesystem: true
          runAsNonRoot: true
          runAsUser: 1000
        terminationMessagePath: /dev/termination-log
        terminationMessagePolicy: File
        volumeMounts:
        - mountPath: /tmp
          name: tmp-dir
      dnsPolicy: ClusterFirst
      hostNetwork: true
      nodeSelector:
        kubernetes.io/arch: amd64
        kubernetes.io/os: linux
      restartPolicy: Always
      schedulerName: default-scheduler
      securityContext: {}
      serviceAccount: metrics-server
      serviceAccountName: metrics-server
      terminationGracePeriodSeconds: 30
      volumes:
      - emptyDir: {}
        name: tmp-dir
status:
  availableReplicas: 1
  conditions:
  - lastTransitionTime: "2020-07-07T13:15:48Z"
    lastUpdateTime: "2020-07-07T13:15:48Z"
    message: Deployment has minimum availability.
    reason: MinimumReplicasAvailable
    status: "True"
    type: Available
  - lastTransitionTime: "2020-07-07T13:15:40Z"
    lastUpdateTime: "2020-07-09T12:50:00Z"
    message: ReplicaSet "metrics-server-548456dbd5" has successfully progressed.
    reason: NewReplicaSetAvailable
    status: "True"
    type: Progressing
  observedGeneration: 2
  readyReplicas: 1
  replicas: 1
  updatedReplicas: 1

Wait a while for metrics-server to collect metrics. Then, we can query the metrics via kubectl

$ kubectl top node
NAME      CPU(cores)   CPU%   MEMORY(bytes)   MEMORY%
master    226m         11%    4957Mi          64%
worker1   83m          4%     2439Mi          66%
worker2   94m          4%     4182Mi          75%