k8s安装metrics-server
Kubernetes Metrics Server：
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Kubernetes Metrics Server 是 Cluster 的核心监控数据的聚合器，kubeadm 默认是不部署的。
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Metrics Server 供 Dashboard 等其他组件使用，是一个扩展的 APIServer，依赖于 API Aggregator。所以，在安装 Metrics Server 之前需要先在 kube-apiserver 中开启 API Aggregator。
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Metrics API 只可以查询当前的度量数据，并不保存历史数据。
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Metrics API URI 为 /apis/metrics.k8s.io/，在 k8s.io/metrics 下维护。
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必须部署 metrics-server 才能使用该 API，metrics-server 通过调用 kubelet Summary API 获取数据。
一、前提条件
注意：使用 Metrics Server 有必备两个条件：
1、API Server 启用 Aggregator Routing 支持。否则 API Server 不识别请求：
Error from server (ServiceUnavailable): the server is currently unable to handle the request (get pods.metrics.k8s.io)
2、API Server 能访问 Metrics Server Pod IP。否则 API Server 无法访问 Metrics Server：
E1223 07:23:04.330206 1 available_controller.go:420] v1beta1.metrics.k8s.io failed with: failing or missing response from https://10.171.248.214:4443/apis/metrics.k8s.io/v1beta1: Get https://10.171.248.214:4443/apis/metrics.k8s.io/v1beta1: net/http: request canceled while waiting for connection (Client.Timeout exceeded while awaiting headers)
3、启用API Aggregator，API Aggregation 允许在不修改 Kubernetes 核心代码的同时扩展 Kubernetes API，即：将第三方服务注册到 Kubernetes API 中，这样就可以通过 Kubernetes API 来访问第三方服务了，例如：Metrics Server API。注：另外一种扩展 Kubernetes API 的方法是使用 CRD（Custom Resource Definition，自定义资源定义）。
二、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@master1 ~]# ps -ef | grep apiserver root 12721 10738 0 20:46 pts/0 00:00:00 grep --color=auto apiserver root 111575 111557 6 16:42 ? 00:16:51 kube-apiserver --advertise-address=192.168.200.3 --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=10.96.0.0/12 --tls-cert-file=/etc/kubernetes/pki/apiserver.crt --tls-private-key-file=/etc/kubernetes/pki/apiserver.key
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。
cat /etc/kubernetes/manifests/kube-apiserver.yaml apiVersion: v1 kind: Pod metadata: annotations: kubeadm.kubernetes.io/kube-apiserver.advertise-address.endpoint: 192.168.200.3:6443 creationTimestamp: null labels: component: kube-apiserver tier: control-plane name: kube-apiserver namespace: kube-system spec: containers: - command: - kube-apiserver - --advertise-address=192.168.200.3 - --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=10.96.0.0/12 - --tls-cert-file=/etc/kubernetes/pki/apiserver.crt - --tls-private-key-file=/etc/kubernetes/pki/apiserver.key image: k8s.gcr.io/kube-apiserver:v1.18.2 imagePullPolicy: IfNotPresent livenessProbe: failureThreshold: 8 httpGet: host: 192.168.200.3 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: {}
github地址：
https://github.com/kubernetes-sigs/metrics-server/releases
三、安装
1、下载yaml文件
wget https://github.com/kubernetes-sigs/metrics-server/releases/download/v0.4.1/components.yaml
2、修改components.yaml文件
cat components.yaml 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: - pods - nodes - nodes/stats - namespaces - configmaps 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=4443 - --kubelet-preferred-address-types=InternalIP # 删掉 ExternalIP,Hostname这两个，这里已经改好了，你那边要自己核对一下 - --kubelet-use-node-status-port - --kubelet-insecure-tls # 加上该启动参数 image: k8s.gcr.io/metrics-server/metrics-server:v0.4.1 # 镜像地址根据情况修改 imagePullPolicy: IfNotPresent livenessProbe: failureThreshold: 3 httpGet: path: /livez port: https scheme: HTTPS periodSeconds: 10 name: metrics-server ports: - containerPort: 4443 name: https protocol: TCP readinessProbe: failureThreshold: 3 httpGet: path: /readyz port: https scheme: HTTPS periodSeconds: 10 securityContext: readOnlyRootFilesystem: true runAsNonRoot: true runAsUser: 1000 volumeMounts: - mountPath: /tmp name: tmp-dir 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
3、安装
kubectl apply -f components.yaml
4、检查 API Server 是否可以连通 Metrics Server
[root@master1 ~]# kubectl describe svc metrics-server -n kube-system Name: metrics-server Namespace: kube-system Labels: kubernetes.io/cluster-service=true kubernetes.io/name=Metrics-server Annotations: Selector: k8s-app=metrics-server Type: ClusterIP IP: 10.107.86.150 Port: <unset> 443/TCP TargetPort: main-port/TCP Endpoints: 10.244.2.20:4443 Session Affinity: None Events: <none> # 在其他几个节点ping一下Endpoints的地址 [root@master3 ~]# ping 10.244.2.20 PING 10.244.2.20 (10.244.2.20) 56(84) bytes of data. 64 bytes from 10.244.2.20: icmp_seq=1 ttl=64 time=0.122 ms 64 bytes from 10.244.2.20: icmp_seq=2 ttl=64 time=0.032 ms
