Kubernetes实战(二十六)-K8S 部署Dashboard UI-编程知识

Kubernetes Dashboard是Kubernetes集群的通用、基于Web的UI。它允许用户管理集群中运行的应用程序并对其进行故障排除，以及管理集群本身。
访问到DashBoard有两种方式：

通过KubernetesAPI访问：Dashboard是Kubernetes的内置的UI插件，由APIServer提供的一个URL提供访问入口：/api/v1/namespaces/kubernetes-dashboard/services/https:kubernetes-dashboard:/proxy，集群外部主机想要访问到Dashboard需要两个条件：kube-proxy创建一个端口并信任允许外部主机访问到KubernetesAPI+HTTPS协议！
通过NodePort类型的Service访问：集群外部主机可直接通过"https://<任一节点主机IP>:"访问到DashBoard。

本文将采用通过NodePort类型的Service访问方式部署Dashboard UI。

参考文档：
GitHub - kubernetes/dashboard: General-purpose web UI for Kubernetes clusters
https://github.com/kubernetes/dashboard/blob/master/docs/user/accessing-dashboard/README.md#login-not-available

1 安装Dashboard

根据配置清单安装Dashboard，会创建Cluster类型的Service，仅只能从集群内部主机访问到Dashboard，所以这边需要简单修改一下，将Service修改为NodePort类型，这样外部主机也可以访问它。

# wget https://raw.githubusercontent.com/kubernetes/dashboard/v2.5.1/aio/deploy/recommended.yaml -O kubernetes-dashboard.yaml
# vim kubernetes-dashboard.yaml
kind: Service
apiVersion: v1
metadata:labels:k8s-app: kubernetes-dashboardname: kubernetes-dashboardnamespace: kubernetes-dashboard
spec:type: NodePortports:- port: 443targetPort: 8443selector:k8s-app: kubernetes-dashboard
# kubectl apply -f kubernetes-dashboard.yaml 
namespace/kubernetes-dashboard created
serviceaccount/kubernetes-dashboard created
service/kubernetes-dashboard created
secret/kubernetes-dashboard-certs created
secret/kubernetes-dashboard-csrf created
secret/kubernetes-dashboard-key-holder created
configmap/kubernetes-dashboard-settings created
role.rbac.authorization.k8s.io/kubernetes-dashboard created
clusterrole.rbac.authorization.k8s.io/kubernetes-dashboard created
rolebinding.rbac.authorization.k8s.io/kubernetes-dashboard created
clusterrolebinding.rbac.authorization.k8s.io/kubernetes-dashboard created
deployment.apps/kubernetes-dashboard created
service/dashboard-metrics-scraper created
deployment.apps/dashboard-metrics-scraper created
# kubectl get pod --namespace=kubernetes-dashboard
NAME                                         READY   STATUS    RESTARTS   AGE
dashboard-metrics-scraper-799d786dbf-xx9j7   1/1     Running   0          3m16s
kubernetes-dashboard-fb8648fd9-rgc2z         1/1     Running   0          3m17s

2 访问到Dashboard

# kubectl get service --namespace=kubernetes-dashboard
NAME                        TYPE        CLUSTER-IP      EXTERNAL-IP   PORT(S)         AGE
dashboard-metrics-scraper   ClusterIP   10.97.23.158    <none>        8000/TCP        4m6s
kubernetes-dashboard        NodePort    10.103.40.153   <none>        443:32358/TCP   4m7s
# netstat -lnupt |grep 32358
tcp        0      0 0.0.0.0:32358           0.0.0.0:*               LISTEN      41631/kube-proxy

3 选择登录到Dashboard要使用的身份认证方式

登录进入Dashboard需要进行身份认证。
Dashboard服务在Pod中运行，Pod想要访问并获取到集群相关信息的话则需要创建一个ServiceAccount以验证身份。
Dashboard想要管理Kubernetes集群需要进行身份认证，目前支持Token和Kubeconfig两种方式。

Token：创建一个拥有集群角色"cluster-admin"的服务账户"dashboard-admin"，然后使用dashboard-admin的Token即可！当然你也可以根据特殊需要创建拥有指定权限的集群角色将其绑定到对应的服务账户上，以管理集群中指定资源。

# 创建一个专用于Dashboard的服务账户"dashboard-admin"
# kubectl create serviceaccount dashboard-admin -n kubernetes-dashboard
serviceaccount/dashboard-admin created
# 为服务账户"dashboard-admin"绑定到拥有超级管理员权限的集群角色"cluster-admin"
# 则dashboard-admin就拥有了超级管理员权限
# kubectl create clusterrolebinding dashboard-admin --clusterrole=cluster-admin --serviceaccount=kubernetes-dashboard:dashboard-admin
clusterrolebinding.rbac.authorization.k8s.io/dashboard-admin created
# 创建的服务账户，会自动生成一个Token，它是Secret类型的资源对象
# 我们可以使用以下操作获取到服务账户"dashboard-admin"的Token以用于Dashboard身份验证
# kubectl get secrets -n kubernetes-dashboard |grep dashboard-admin-token
dashboard-admin-token-2bxfl        kubernetes.io/service-account-token   3      66s
# kubectl describe secrets/dashboard-admin-token-2bxfl -n kubernetes-dashboard
Name:         dashboard-admin-token-2bxfl
Namespace:    kubernetes-dashboard
Labels:       <none>
Annotations:  kubernetes.io/service-account.name: dashboard-adminkubernetes.io/service-account.uid: 492a031e-db41-4a65-a8d4-af0e240e7f9dType:  kubernetes.io/service-account-tokenData
====
ca.crt:     1103 bytes
namespace:  20 bytes
token:      eyJhbGciOiJSUzI1NiIsImtpZCI6ImFXTzZFUElaS2RoTUpScHFwNzJSNUN5eU1lcFNSZEZqNWNNbi1VbFV2Zk0ifQ.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.l5VEIPd9nIsJuXMh86rjFHhkIoZmg5nlDw7Bixn0b3-KT1r6o7WRegq8DJyVk_iiIfRnrrz5jjuOOkCKwXwvI1NCfVdsuBKXFwFZ1Crc-BwHjIxWbGuZfEGxSbN8du4T4xcUuNU-7HuZQcGDY23uy68aPqWSm8UoIcOFwUgVcYkKlOuW76tIXxG_upxWpWZz74aMDUIkjar7sdWXzMr1m5G43TLE9Z_lKCgoV-hc4Fo9_Er-TIAPqDG6-sfZZZ9Raldvn3j380QDYahUKaGKabnOFDXbODKOQ1VKRizgiRTOqt-z9YRPTcyxQzfheKC8DTb2X8D-E4x6azulenNgqw

Kubeconfig：Token是很长的复杂的密钥字符串，使用它进行身份认证并不方便，所以Dashboard支持使用Kubeconfig文件的方式登陆到Dashboard。
基于上面Token的创建的服务账户，创建一个Kubeconfig配置文件。

# 查看集群信息
# kubectl cluster-info
Kubernetes control plane is running at https://192.168.124.100:9443
# 创建kubeconfig文件并设置集群相关
# kubectl config set-cluster kubernetes --embed-certs=true --server="https://192.168.124.100:9443" --certificate-authority=/etc/kubernetes/pki/ca.crt --kubeconfig=dashboard-admin.kubeconfig
# 设置认证相关到kubeconfig文件
# 默认情况下服务账户的Token是base64编码格式，如果需要将其写到kubeconfig中的则需要使用"base64 -d"进行解
# 码
# Token=$(kubectl get secrets/dashboard-admin-token-2bxfl -n kubernetes-dashboard -o jsonpath={.data.token} |base64 -d)
# kubectl config set-credentials dashboard-admin --token=${Token} --kubeconfig=./dashboard-admin.kubeconfig 
# 设置上下文相关到kubeconfig文件
# kubectl config set-context dashboard-admin --cluster=kubernetes  --user=dashboard-admin --kubeconfig=./dashboard-admin.kubeconfig 
# 设置当前要使用的上下文到kubeconfig文件
# kubectl config use-context dashboard-admin --cluster=kubernetes  --user=dashboard-admin --kubeconfig=./dashboard-admin.kubeconfig
# 最后得到以下文件
# cat dashboard-admin.kubeconfig
apiVersion: v1
clusters:
- cluster:certificate-authority-data: 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server: https://192.168.124.100:9443name: kubernetes
contexts:
- context:cluster: kubernetesuser: dashboard-adminname: dashboard-admin
current-context: dashboard-admin
kind: Config
preferences: {}
users:
- name: dashboard-adminuser:token: eyJhbGciOiJSUzI1NiIsImtpZCI6ImFXTzZFUElaS2RoTUpScHFwNzJSNUN5eU1lcFNSZEZqNWNNbi1VbFV2Zk0ifQ.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.l5VEIPd9nIsJuXMh86rjFHhkIoZmg5nlDw7Bixn0b3-KT1r6o7WRegq8DJyVk_iiIfRnrrz5jjuOOkCKwXwvI1NCfVdsuBKXFwFZ1Crc-BwHjIxWbGuZfEGxSbN8du4T4xcUuNU-7HuZQcGDY23uy68aPqWSm8UoIcOFwUgVcYkKlOuW76tIXxG_upxWpWZz74aMDUIkjar7sdWXzMr1m5G43TLE9Z_lKCgoV-hc4Fo9_Er-TIAPqDG6-sfZZZ9Raldvn3j380QDYahUKaGKabnOFDXbODKOQ1VKRizgiRTOqt-z9YRPTcyxQzfheKC8DTb2X8D-E4x6azulenNgqw