部署kubernetes-dashboard并配置ServiceAccount和登录鉴权

"种草" kubernetes-dashboard

Kubernetes Dashboard 是通用的用于管理 Kubernetes 集群的 WebUI面板

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kubernetes-dashboard 代码库 readme 中对自己的介绍:

Kubernetes Dashboard is a general purpose, web-based UI for Kubernetes clusters. It allows users to manage applications running in the cluster and troubleshoot them, as well as manage the cluster itself.

通过这个面板, 可以让我们非常直观看到pod的状态, 创建时间, 标签, 运行在哪个结点等元数据

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还能看到容器中定义的环境变量, 挂载的磁盘, livenessreadiness探针等信息

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有了这个面板, 不光是pod, 可以对几乎 kubernetes 中的任何资源(前提是当前用户有足够的权限) 查看和管理

再介绍一个这个面板我自己最常用的功能: 重启pod

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确实通过命令kubectl rollout restart -n prod deployment mysql-8-0可以实现同样的操作, 不过有了这个面板, 鼠标点点就能完成岂不美哉, 重启前还会弹出确认框提示你是不是确定要重启, 还贴心的把用于重启命令给我们展示出来了, awesome! 再也不怕忘记命令每次都要去google一下文档啦!

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这个面板可以使用kubernetes的ServiceAccount来登录鉴权, 对权限控制的粒度可以做到非常细致, 别急, 往下看!

安装部署dashboard

官方的deployment.yaml

这份文件中, 首先定义了个Namespace -> kubernetes-dashboard, 然后的所有资源都在这个Namespace下;

先看2个Deployment的定义, 分别是kubernetes-dashboarddashboard-metrics-scraper

点击展开 -> Deployment: 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:
      securityContext:
        seccompProfile:
          type: RuntimeDefault
      containers:
        - name: kubernetes-dashboard
          image: kubernetesui/dashboard:v2.7.0
          imagePullPolicy: Always
          ports:
            - containerPort: 8443
              protocol: TCP
          args:
            - --auto-generate-certificates
            - --namespace=kubernetes-dashboard
            # 通过nginx-ingress暴露出去, 这里不需要ssl了, 没有这个标志位会导致无法正常登录
            - --enable-insecure-login=true
          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:
        "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
点击展开 -> Deployment: 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
    spec:
      securityContext:
        seccompProfile:
          type: RuntimeDefault
      containers:
        - name: dashboard-metrics-scraper
          image: kubernetesui/metrics-scraper:v1.0.8
          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:
        "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: {}

再看ServiceAccount: kubernetes-dashboard; 上面两个Deployment kubernetes-dashboarddashboard-metrics-scraper 中的容器都绑定到了这个ServiceAccount

点击展开 ServiceAccount: kubernetes-dashboard
apiVersion: v1
kind: ServiceAccount
metadata:
  labels:
    k8s-app: kubernetes-dashboard
  name: kubernetes-dashboard
  namespace: kubernetes-dashboard

deployment.yaml中还定义了ClusterRole: kubernetes-dashboardRole: kubernetes-dashboard, ClusterRole Role中定义了面板所需的权限

ClusterRole和Role的定义
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"]

ClusterRole, Role与 前面提到的 ServiceAccount:kubernetes-dashboard 通过 ClusterRoleBindingRoleBinding 绑定到了一起, 就是给 ServiceAccount:kubernetes-dashboard 授权, 让它可以访问集群里的资源

ClusterRoleBinding, RoleBinding 绑定 ServiceAccount 与 ClusterRole, Role
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

最后就是 Service, ConfigMap, 和几个ssl相关的 Secret, 几个 Secret 的定义对我来说是不重要的, 因为上面Deployment容器的启动命令里, 我加上了 --enable-insecure-login=true, 我在外部通过nginx-ingress暴露服务, 配置好了ingress的部分配置ssl, 所里这里就无所谓了

kind: Service
apiVersion: v1
metadata:
  labels:
    k8s-app: kubernetes-dashboard
  name: kubernetes-dashboard
  namespace: kubernetes-dashboard
spec:
  ports:
    - port: 443
      targetPort: 8443
  selector:
    k8s-app: kubernetes-dashboard

---

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: ConfigMap
apiVersion: v1
metadata:
  labels:
    k8s-app: kubernetes-dashboard
  name: kubernetes-dashboard-settings
  namespace: 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

配置Ingress, 向外暴露服务

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  namespace: kubernetes-dashboard
  name: kubernetes-dashboard-ingress
  annotations:
    kubernetes.io/ingress.class: nginx
    nginx.ingress.kubernetes.io/backend-protocol: http
spec:
  ingressClassName: 
  tls:
    - hosts:
        - <这里填域名>
      secretName: <这里填集群内配置好的Secret证书>
  rules:
    - host: <这里填域名>
      http:
        paths:
        - path: /
          pathType: Prefix
          backend:
            service:
              name: kubernetes-dashboard
              port:
                number: 80

创建用于登录面板的ServiceAccount

新建account.yaml中定义ServiceAccount并绑定到内置的ClusterRole

定义两个 ServiceAccount 分别是 rootreadonly

  • root 绑定到内置的 ClusterRole cluster-admin
  • readonly 绑定到内置的 ClusterRole view
  • kubectl get clusterrole 可以列表当前集群中已存在的角色
apiVersion: v1
kind: ServiceAccount
metadata:
  name: root
  namespace: kubernetes-dashboard

---

apiVersion: v1
kind: ServiceAccount
metadata:
  name: readonly
  namespace: kubernetes-dashboard

---

apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:
  name: root
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: cluster-admin
subjects:
- kind: ServiceAccount
  name: root
  namespace: kubernetes-dashboard

---

apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:
  name: readonly
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: view
subjects:
- kind: ServiceAccount
  name: readonly
  namespace: kubernetes-dashboard

kubectl apply -f account.yaml 应用后, rootreadonly 就创建好了, 然后我们去生成 Token 输入到面板的登录界面中就可以登录了

root 生成有效期30天 Token 的命令 kubectl create token --namespace kubernetes-dashboard --duration 2592000s root

Token 登录

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权限控制

root 账户绑定的角色是内置的 cluster-admin, 可以对集群内的一切资源进行查看或修改, 删除等操作

readonly 账户绑定的角色是内置的 view, 拥有对集群内大部分资源的只读权限

也可以自己新建一个角色, 授予这个新角色某些指定权限, 例如下面的示例, 创建了一个名为 testClusterRole, 对pods有只读权限, 然后将这个角色与 ServiceAccount 绑定

kind: ClusterRole
apiVersion: rbac.authorization.k8s.io/v1
metadata:
  name: test
rules:
  - apiGroups: [""] 
    resources: ["pods"]
    verbs: ["get", "watch", "list"]

---

apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:
  name: root-to-test
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: test
subjects:
- kind: ServiceAccount
  name: root
  namespace: kubernetes-dashboard
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