k8s-v1.18安装Metrics-Server

Metrics-Server概念介绍

Metrics-Server是集群核心监控数据的聚合器，在k8s早期版本中，对资源的监控使用的是heapster的资源监控工具。但是从 Kubernetes 1.8 开始，Kubernetes 通过 Metrics API 获取资源使用指标，例如容器 CPU 和内存使用情况。这些度量指标可以由用户直接访问，例如通过使用kubectl top 命令，或者使用集群中的控制器，,因为k8s的api-server将所有的数据持久化到了etcd中，显然k8s本身不能处理这种频率的采集，而且这种监控数据变化快且都是临时数据，因此需要有一个组件单独处理他们.

环境：K8s-v1.18、Docker-18.06.1-ce

一、修改配置

1、检查 API Server 是否开启了 Aggregator Routing：查看 API Server 是否具有 --enable-aggregator-routing=true 选项。

[root@k8s-master manifests]# ps -ef | grep apiserver

root      22008  21989  4 19:33 ?        00:06:37 kube-apiserver --advertise-address=192.168.181.142 --allow-privileged=true --authorization-mode=Node,RBAC --client-ca-file=/etc/kubernetes/pki/ca.crt --enable-admission-plugins=NodeRestriction --enable-bootstrap-token-auth=true  --etcd-cafile=/etc/kubernetes/pki/etcd/ca.crt --etcd-certfile=/etc/kubernetes/pki/apiserver-etcd-client.crt --etcd-keyfile=/etc/kubernetes/pki/apiserver-etcd-client.key --etcd-servers=https://127.0.0.1:2379 --insecure-port=0 --kubelet-client-certificate=/etc/kubernetes/pki/apiserver-kubelet-client.crt --kubelet-client-key=/etc/kubernetes/pki/apiserver-kubelet-client.key --kubelet-preferred-address-types=InternalIP,ExternalIP,Hostname --proxy-client-cert-file=/etc/kubernetes/pki/front-proxy-client.crt --proxy-client-key-file=/etc/kubernetes/pki/front-proxy-client.key --requestheader-allowed-names=front-proxy-client --requestheader-client-ca-file=/etc/kubernetes/pki/front-proxy-ca.crt --requestheader-extra-headers-prefix=X-Remote-Extra- --requestheader-group-headers=X-Remote-Group --requestheader-username-headers=X-Remote-User --secure-port=6443 --service-account-key-file=/etc/kubernetes/pki/sa.pub --service-cluster-ip-range=10.1.0.0/16 --tls-cert-file=/etc/kubernetes/pki/apiserver.crt --tls-private-key-file=/etc/kubernetes/pki/apiserver.key

root      66924  57038  0 21:47 pts/0    00:00:00 grep --color=auto apiserver

2、修改每个 API Server 的 kube-apiserver.yaml 配置开启 Aggregator Routing：修改 manifests 配置后 API Server 会自动重启生效。

vim /etc/kubernetes/manifests/kube-apiserver.yaml

apiVersion: v1

kind: Pod

metadata:

  annotations:

    kubeadm.kubernetes.io/kube-apiserver.advertise-address.endpoint: 192.168.10.253:6443

  creationTimestamp: null

  labels:

    component: kube-apiserver

    tier: control-plane

  name: kube-apiserver

  namespace: kube-system

spec:

  containers:

  - command:

    - kube-apiserver

    - --advertise-address=192.168.10.253

    - --allow-privileged=true

    - --authorization-mode=Node,RBAC

    - --client-ca-file=/etc/kubernetes/pki/ca.crt

    - --enable-admission-plugins=NodeRestriction

    - --enable-bootstrap-token-auth=true

    - --enable-aggregator-routing=true #添加本行

    - --etcd-cafile=/etc/kubernetes/pki/etcd/ca.crt

    - --etcd-certfile=/etc/kubernetes/pki/apiserver-etcd-client.crt

    - --etcd-keyfile=/etc/kubernetes/pki/apiserver-etcd-client.key

    - --etcd-servers=https://127.0.0.1:2379

    - --insecure-port=0

    - --kubelet-client-certificate=/etc/kubernetes/pki/apiserver-kubelet-client.crt

    - --kubelet-client-key=/etc/kubernetes/pki/apiserver-kubelet-client.key

    - --kubelet-preferred-address-types=InternalIP,ExternalIP,Hostname

    - --proxy-client-cert-file=/etc/kubernetes/pki/front-proxy-client.crt

    - --proxy-client-key-file=/etc/kubernetes/pki/front-proxy-client.key

    - --requestheader-allowed-names=front-proxy-client

    - --requestheader-client-ca-file=/etc/kubernetes/pki/front-proxy-ca.crt

    - --requestheader-extra-headers-prefix=X-Remote-Extra-

    - --requestheader-group-headers=X-Remote-Group

    - --requestheader-username-headers=X-Remote-User

    - --secure-port=6443

    - --service-account-key-file=/etc/kubernetes/pki/sa.pub

    - --service-cluster-ip-range=10.1.0.0/16

    - --tls-cert-file=/etc/kubernetes/pki/apiserver.crt

    - --tls-private-key-file=/etc/kubernetes/pki/apiserver.key

    image: registry.aliyuncs.com/google_containers/kube-apiserver:v1.18.0

    imagePullPolicy: IfNotPresent

    livenessProbe:

      failureThreshold: 8

      httpGet:

        host: 192.168.10.253

        path: /healthz

        port: 6443

        scheme: HTTPS

      initialDelaySeconds: 15

      timeoutSeconds: 15

    name: kube-apiserver

    resources:

      requests:

        cpu: 250m

    volumeMounts:

    - mountPath: /etc/ssl/certs

      name: ca-certs

      readOnly: true

    - mountPath: /etc/pki

      name: etc-pki

      readOnly: true

    - mountPath: /etc/kubernetes/pki

      name: k8s-certs

      readOnly: true

  hostNetwork: true

  priorityClassName: system-cluster-critical

  volumes:

  - hostPath:

      path: /etc/ssl/certs

      type: DirectoryOrCreate

    name: ca-certs

  - hostPath:

      path: /etc/pki

      type: DirectoryOrCreate

    name: etc-pki

  - hostPath:

      path: /etc/kubernetes/pki

      type: DirectoryOrCreate

    name: k8s-certs

status: {}

二、安装metrics-server(v0.3.6)

1、下载yaml文件

wget https://github.com/kubernetes-sigs/metrics-server/releases/download/v0.3.6/components.yaml

2、修改components.yaml文件

apiVersion: rbac.authorization.k8s.io/v1

kind: ClusterRole

metadata:

  name: system:aggregated-metrics-reader

  labels:

    rbac.authorization.k8s.io/aggregate-to-view: "true"

    rbac.authorization.k8s.io/aggregate-to-edit: "true"

    rbac.authorization.k8s.io/aggregate-to-admin: "true"

rules:

- apiGroups: ["metrics.k8s.io"]

  resources: ["pods", "nodes"]

  verbs: ["get", "list", "watch"]

---

apiVersion: rbac.authorization.k8s.io/v1

kind: ClusterRoleBinding

metadata:

  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: RoleBinding

metadata:

  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: apiregistration.k8s.io/v1beta1

kind: APIService

metadata:

  name: v1beta1.metrics.k8s.io

spec:

  service:

    name: metrics-server

    namespace: kube-system

  group: metrics.k8s.io

  version: v1beta1

  insecureSkipTLSVerify: true

  groupPriorityMinimum: 100

  versionPriority: 100

---

apiVersion: v1

kind: ServiceAccount

metadata:

  name: metrics-server

  namespace: kube-system

---

apiVersion: apps/v1

kind: Deployment

metadata:

  name: metrics-server

  namespace: kube-system

  labels:

    k8s-app: metrics-server

spec:

  selector:

    matchLabels:

      k8s-app: metrics-server

  template:

    metadata:

      name: metrics-server

      labels:

        k8s-app: metrics-server

    spec:

      serviceAccountName: metrics-server

      volumes:

      # mount in tmp so we can safely use from-scratch images and/or read-only containers

      - name: tmp-dir

        emptyDir: {}

      containers:

      - name: metrics-server

      image: registry.aliyuncs.com/google_containers/metrics-server-amd64:v0.3.6 #修改为阿里云的镜像地址

        imagePullPolicy: IfNotPresent

        args:

          - --cert-dir=/tmp

          - --secure-port=4443

          - /metrics-server #新增

          - --kubelet-preferred-address-types=InternalIP #新增

          - --kubelet-insecure-tls #新增

        ports:

        - name: main-port

          containerPort: 4443

          protocol: TCP

        securityContext:

          readOnlyRootFilesystem: true

          runAsNonRoot: true

          runAsUser: 1000

        volumeMounts:

        - name: tmp-dir

          mountPath: /tmp

      nodeSelector:

        kubernetes.io/os: linux

        kubernetes.io/arch: "amd64"

---

apiVersion: v1

kind: Service

metadata:

  name: metrics-server

  namespace: kube-system

  labels:

    kubernetes.io/name: "Metrics-server"

    kubernetes.io/cluster-service: "true"

spec:

  selector:

    k8s-app: metrics-server

  ports:

  - port: 443

    protocol: TCP

    targetPort: main-port

---

apiVersion: rbac.authorization.k8s.io/v1

kind: ClusterRole

metadata:

  name: system:metrics-server

rules:

- apiGroups:

  - ""

  resources:

  - pods

  - nodes

  - nodes/stats

  - namespaces

  - configmaps

  verbs:

  - get

  - list

  - watch

---

apiVersion: rbac.authorization.k8s.io/v1

kind: ClusterRoleBinding

metadata:

  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

3、安装

kubectl apply -f components.yaml

4、查看metrics-server服务状态

[root@k8s-master manifests]# kubectl get pod -n kube-system | grep metrics-server

metrics-server-59dd47f7d9-qbsgq      1/1    Running  0          9m32s

5、检查接口是否有异常

[root@k8s-master manifests]# kubectl describe apiservice v1beta1.metrics.k8s.io

Name:        v1beta1.metrics.k8s.io

Namespace:   

Labels:      <none>

Annotations:  API Version:  apiregistration.k8s.io/v1

Kind:        APIService

Metadata:

  Creation Timestamp:  2021-02-26T07:55:08Z

  Resource Version:    1948553

  Self Link:          /apis/apiregistration.k8s.io/v1/apiservices/v1beta1.metrics.k8s.io

  UID:                515535ec-3766-4d8a-a6fe-c7b21781ae81

Spec:

  Group:                    metrics.k8s.io

  Group Priority Minimum:    100

  Insecure Skip TLS Verify:  true

  Service:

    Name:            metrics-server

    Namespace:      kube-system

    Port:            443

  Version:          v1beta1

  Version Priority:  100

Status:

  Conditions:

    Last Transition Time:  2021-02-26T07:55:15Z

    Message:              all checks passed

    Reason:                Passed

    Status:                True

    Type:                  Available

Events:                    <none>

6、执行以下命令，检查节点占用性能情况。

[root@k8s-master manifests]# kubectl top nodes

NAME        CPU(cores)  CPU%  MEMORY(bytes)  MEMORY% 

k8s-master  261m        6%    1222Mi          15%     

k8s-node1    144m        3%    702Mi          9%       

k8s-node2    50m          5%    535Mi          31%

[root@k8s-master manifests]# kubectl top pods

NAME                  CPU(cores)  MEMORY(bytes) 

liu-nginx              0m          6Mi           

nginx                  0m          4Mi           

web-694d958794-52mj9  1m          3Mi           

web-694d958794-dmpv8  1m          3Mi           

web-694d958794-tv6nc  1m          5Mi