导读
经过前面k8s系列的文章,这一系列已经基本完成,现在就用几篇文章说一下日常的集群维护。
目录
更新资源对象的Label
Namespace:集群环境共享与隔离
部署集群监控
部署Web UI管理集群:Dashboard
更新资源对象的Label
比如对Pod进行Label的增删改。
新增:
kubectl label pod pod-name key=value
修改:
kubelet label pod pod-name key=value --overwrite
删除
kubelet label pod pod-name label_key
Namespace:集群环境共享与隔离
不同的工作组可以在同一个k8s集群中工作,k8s通过命名空间和Context的设置对不同的工作组进行区分,让它们可以在同一个k8s集群中工作
(1)定义Context
需要为每个工作组分别设置一个Context,即运行环境,这个运行环境属于某个命名空间
通过kubectl context set-context命令定义Context,并将Context置于某个命名空间中
例如:创建一个名为context-test1的context,绑定命名空间context-text
创建一个集群名称:
kubectl config set-cluster kubernetes --server=https://localhost:8080 kubectl config set-context context-test1 --namespace=context-text --cluster=kubernetes
使用kubectl config view命令查看已定义的Context(不知道集群名也可以使用此命令查看)
kubectl config view
通过kubectl config命令在${HOME}/.kube目录下生成了一个名为config的文件,文件的内容为以kubectl config view命令查看到的内容。所以也可以通过手工编辑该文件的方式来设置Context。
(2)设置工作组在特定Context环境工作
使用如下命令设置当前运行环境
kubectl config use-context context-test1
之后所有操作都会在context-test1环境绑定的命名空间中完成。
部署集群监控
在Kubernetes新的监控体系中,Metrics Server用于提供核心指标(Core Metrics),包括Node、Pod的CPU和内存使用指标。对其他自定义指标(Custom Metrics)的监控则由Prometheus等组件来完成。
通过Metrics Server监控Pod和Node的CPU和内存资源使用数据。
Metrics Server在部署完成后,将通过Kubernetes核心API Server的“/apis/metrics.k8s.io/v1beta1”路径提供Pod和Node的监控数据。Metrics Server源代码和部署配置可以在GitHub代码库(https://github.com/kubernetes-incubator/metrics-server)找到。
首先,部署Metrics Server实例,
从https://github.com/kubernetes-sigs/metrics-server/releases/download/v0.3.7/components.yaml获取到最新的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: yakdhane/metrics-server:v0.3.7 imagePullPolicy: IfNotPresent args: - --cert-dir=/tmp - --secure-port=4443 command: - /metrics-server - --metric-resolution=30s - --kubelet-insecure-tls - --kubelet-preferred-address-types=InternalIP 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 --- 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
yaml文件需要修改,添加以下内容:
如果不添加上述内容,启动会报错
- –kubelet-preferred-address-types 改为支持ip通信,InternalIP(default [Hostname,InternalDNS,InternalIP,ExternalDNS,ExternalIP])
- –kubelet-insecure-tls 忽略证书错误
在部署完成后确保metrics-server的Pod启动成功:
kubectl -n kube-system get pod -l k8s-app=metrics-server
使用kubectl top nodes和kubectl top pods命令监控CPU和内存资源的使用情况:
Metrics Server提供的数据也可以供HPA控制器使用,以实现基于CPU使用率或内存使用值的Pod自动扩缩容功能。
部署Web UI管理集群
Kubernetes的Web UI网页管理工具kubernetes-dashboard可提供部署应用、资源对象管理、容器日志查询、系统监控等常用的集群管理功能。为了在页面上显示系统资源的使用情况,要求部署Metrics Server。
可通过https://rawgit.com/kubernetes/dashboard/master/src/deploy/kubernetes-dashboard.yaml页面下载部署kubernetes- dashboard的YAML配置文件。
其中包含Deployment和Service的定义:
# Copyright 2017 The Kubernetes Authors. # # Licensed under the Apache License, Version 2.0 (the "License"); # you may not use this file except in compliance with the License. # You may obtain a copy of the License at # # http://www.apache.org/licenses/LICENSE-2.0 # # Unless required by applicable law or agreed to in writing, software # distributed under the License is distributed on an "AS IS" BASIS, # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. # See the License for the specific language governing permissions and # limitations under the License. apiVersion: v1 kind: Namespace metadata: name: kubernetes-dashboard --- apiVersion: v1 kind: ServiceAccount metadata: labels: k8s-app: kubernetes-dashboard name: kubernetes-dashboard namespace: kubernetes-dashboard --- kind: Service apiVersion: v1 metadata: labels: k8s-app: kubernetes-dashboard name: kubernetes-dashboard namespace: kubernetes-dashboard spec: type: NodePort ports: - port: 443 targetPort: 8443 nodePort: 9090 selector: k8s-app: kubernetes-dashboard --- apiVersion: v1 kind: Secret metadata: labels: k8s-app: kubernetes-dashboard name: kubernetes-dashboard-certs namespace: kubernetes-dashboard type: Opaque --- apiVersion: v1 kind: Secret metadata: labels: k8s-app: kubernetes-dashboard name: kubernetes-dashboard-csrf namespace: kubernetes-dashboard type: Opaque data: csrf: "" --- apiVersion: v1 kind: Secret metadata: labels: k8s-app: kubernetes-dashboard name: kubernetes-dashboard-key-holder namespace: kubernetes-dashboard type: Opaque --- kind: ConfigMap apiVersion: v1 metadata: labels: k8s-app: kubernetes-dashboard name: kubernetes-dashboard-settings namespace: kubernetes-dashboard --- kind: Role apiVersion: rbac.authorization.k8s.io/v1 metadata: labels: k8s-app: kubernetes-dashboard name: kubernetes-dashboard namespace: kubernetes-dashboard rules: # Allow Dashboard to get, update and delete Dashboard exclusive secrets. - apiGroups: [""] resources: ["secrets"] resourceNames: ["kubernetes-dashboard-key-holder", "kubernetes-dashboard-certs", "kubernetes-dashboard-csrf"] verbs: ["get", "update", "delete"] # Allow Dashboard to get and update 'kubernetes-dashboard-settings' config map. - apiGroups: [""] resources: ["configmaps"] resourceNames: ["kubernetes-dashboard-settings"] verbs: ["get", "update"] # Allow Dashboard to get metrics. - apiGroups: [""] resources: ["services"] resourceNames: ["heapster", "dashboard-metrics-scraper"] verbs: ["proxy"] - apiGroups: [""] resources: ["services/proxy"] resourceNames: ["heapster", "http:heapster:", "https:heapster:", "dashboard-metrics-scraper", "http:dashboard-metrics-scraper"] verbs: ["get"] --- kind: ClusterRole apiVersion: rbac.authorization.k8s.io/v1 metadata: labels: k8s-app: kubernetes-dashboard name: kubernetes-dashboard rules: # Allow Metrics Scraper to get metrics from the Metrics server - apiGroups: ["metrics.k8s.io"] resources: ["pods", "nodes"] verbs: ["get", "list", "watch"] --- apiVersion: rbac.authorization.k8s.io/v1 kind: RoleBinding metadata: labels: k8s-app: kubernetes-dashboard name: kubernetes-dashboard namespace: kubernetes-dashboard roleRef: apiGroup: rbac.authorization.k8s.io kind: Role name: kubernetes-dashboard subjects: - kind: ServiceAccount name: kubernetes-dashboard namespace: kubernetes-dashboard --- apiVersion: rbac.authorization.k8s.io/v1 kind: ClusterRoleBinding metadata: name: kubernetes-dashboard roleRef: apiGroup: rbac.authorization.k8s.io kind: ClusterRole name: kubernetes-dashboard subjects: - kind: ServiceAccount name: kubernetes-dashboard namespace: kubernetes-dashboard --- kind: Deployment apiVersion: apps/v1 metadata: labels: k8s-app: kubernetes-dashboard name: kubernetes-dashboard namespace: kubernetes-dashboard spec: replicas: 1 revisionHistoryLimit: 10 selector: matchLabels: k8s-app: kubernetes-dashboard template: metadata: labels: k8s-app: kubernetes-dashboard spec: containers: - name: kubernetes-dashboard image: kubernetesui/dashboard:v2.0.0-rc3 imagePullPolicy: Always ports: - containerPort: 8443 protocol: TCP args: - --auto-generate-certificates - --namespace=kubernetes-dashboard # Uncomment the following line to manually specify Kubernetes API server Host # If not specified, Dashboard will attempt to auto discover the API server and connect # to it. Uncomment only if the default does not work. # - --apiserver-host=http://my-address:port volumeMounts: - name: kubernetes-dashboard-certs mountPath: /certs # Create on-disk volume to store exec logs - mountPath: /tmp name: tmp-volume livenessProbe: httpGet: scheme: HTTPS path: / port: 8443 initialDelaySeconds: 30 timeoutSeconds: 30 securityContext: allowPrivilegeEscalation: false readOnlyRootFilesystem: true runAsUser: 1001 runAsGroup: 2001 volumes: - name: kubernetes-dashboard-certs secret: secretName: kubernetes-dashboard-certs - name: tmp-volume emptyDir: {} serviceAccountName: kubernetes-dashboard nodeSelector: "beta.kubernetes.io/os": linux # Comment the following tolerations if Dashboard must not be deployed on master tolerations: - key: node-role.kubernetes.io/master effect: NoSchedule --- kind: Service apiVersion: v1 metadata: labels: k8s-app: dashboard-metrics-scraper name: dashboard-metrics-scraper namespace: kubernetes-dashboard spec: ports: - port: 8000 targetPort: 8000 selector: k8s-app: dashboard-metrics-scraper --- kind: Deployment apiVersion: apps/v1 metadata: labels: k8s-app: dashboard-metrics-scraper name: dashboard-metrics-scraper namespace: kubernetes-dashboard spec: replicas: 1 revisionHistoryLimit: 10 selector: matchLabels: k8s-app: dashboard-metrics-scraper template: metadata: labels: k8s-app: dashboard-metrics-scraper annotations: seccomp.security.alpha.kubernetes.io/pod: 'runtime/default' spec: containers: - name: dashboard-metrics-scraper image: kubernetesui/metrics-scraper:v1.0.3 ports: - containerPort: 8000 protocol: TCP livenessProbe: httpGet: scheme: HTTP path: / port: 8000 initialDelaySeconds: 30 timeoutSeconds: 30 volumeMounts: - mountPath: /tmp name: tmp-volume securityContext: allowPrivilegeEscalation: false readOnlyRootFilesystem: true runAsUser: 1001 runAsGroup: 2001 serviceAccountName: kubernetes-dashboard nodeSelector: "beta.kubernetes.io/os": linux # Comment the following tolerations if Dashboard must not be deployed on master tolerations: - key: node-role.kubernetes.io/master effect: NoSchedule volumes: - name: tmp-volume emptyDir: {}
这里,Service设置了NodePort映射到物理机的端口号,用于客户端浏览器访问。
创建ServiceAccount,ClusterRoleBinding,绑定cluster-admin的ClusterRole,允许访问所有资源。
--- apiVersion: v1 kind: ServiceAccount metadata: labels: k8s-app: kubernetes-dashboard name: kubernetes-dashboard-admin namespace: kube-system --- apiVersion: rbac.authorization.k8s.io/v1beta1 kind: ClusterRoleBinding metadata: name: kubernetes-dashboard-admin labels: k8s-app: kubernetes-dashboard roleRef: apiGroup: rbac.authorization.k8s.io kind: ClusterRole name: cluster-admin subjects: - kind: ServiceAccount name: kubernetes-dashboard-admin namespace: kube-system
打开浏览器,输入某Node的IP和9090端口号,例如https://cnode-1:9090/#/login,就能访问Dashboard的页面了
选择Token方式登陆,
利用下列命令获取Token:
kubectl -n kube-system describe secret $(kubectl -n kube-system get secret | grep kubernetes-dashboard-admin-token | awk '{print $1}')
登录之后就可以看到集群的全部信息了(包括对资源的增删改查等管理):
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