背景

前面介绍了kubernetes集群部署，如果想更直观地管理和监控k8s集群状况，kubernets-dashboard是一个比较大众的方式。dashboard提供了一个UI界面，使我们可以在页面上查看kubernetes的集群状态以及对集群进行相关的操作，大大便利了我们管理k8s集群。

这里就介绍一下dashboard的部署。

部署

1：nodes节点上从阿里云的docker仓库下载Dashboard的相关镜像。

# docker pull registry.cn-hangzhou.aliyuncs.com/capfgd/kubernetes-dashboard-amd64:v1.8.3

2：修改tag名称。

# docker tag registry.cn-hangzhou.aliyuncs.com/capfgd/kubernetes-dashboard-amd64:v1.8.3 k8s.gcr.io/kubernetes-dashboard-amd64:v1.8.3

3：从官方网站上下载dashboard的yaml编排文件，并进行相应的修改。

下载地址：https://raw.githubusercontent.com/kubernetes/dashboard/master/src/deploy/recommended/kubernetes-dashboard.yaml

kubernetes-dashboard.yaml文件的内容大概如下：

# 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.
# Configuration to deploy release version of the Dashboard UI compatible with
# Kubernetes 1.8.
#
# Example usage: kubectl create -f <this_file>
# ------------------- Dashboard Secret ------------------- #
apiVersion: v1
kind: Secret
metadata:labels:k8s-app: kubernetes-dashboardname: kubernetes-dashboard-certsnamespace: kube-system
type: Opaque
---
# ------------------- Dashboard Service Account ------------------- #
apiVersion: v1
kind: ServiceAccount
metadata:labels:k8s-app: kubernetes-dashboardname: kubernetes-dashboardnamespace: kube-system
---
# ------------------- Dashboard Role & Role Binding ------------------- #
kind: Role
apiVersion: rbac.authorization.k8s.io/v1
metadata:name: kubernetes-dashboard-minimalnamespace: kube-system
rules:# Allow Dashboard to create 'kubernetes-dashboard-key-holder' secret.
- apiGroups: [""]resources: ["secrets"]verbs: ["create"]# Allow Dashboard to create 'kubernetes-dashboard-settings' config map.
- apiGroups: [""]resources: ["configmaps"]verbs: ["create"]# Allow Dashboard to get, update and delete Dashboard exclusive secrets.
- apiGroups: [""]resources: ["secrets"]resourceNames: ["kubernetes-dashboard-key-holder", "kubernetes-dashboard-certs"]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 from heapster.
- apiGroups: [""]resources: ["services"]resourceNames: ["heapster"]verbs: ["proxy"]
- apiGroups: [""]resources: ["services/proxy"]resourceNames: ["heapster", "http:heapster:", "https:heapster:"]verbs: ["get"]
---
apiVersion: rbac.authorization.k8s.io/v1
kind: RoleBinding
metadata:name: kubernetes-dashboard-minimalnamespace: kube-system
roleRef:apiGroup: rbac.authorization.k8s.iokind: Rolename: kubernetes-dashboard-minimal
subjects:
- kind: ServiceAccountname: kubernetes-dashboardnamespace: kube-system
---
# ------------------- Dashboard Deployment ------------------- #
kind: Deployment
apiVersion: apps/v1beta2
metadata:labels:k8s-app: kubernetes-dashboardname: kubernetes-dashboardnamespace: kube-system
spec:replicas: 1revisionHistoryLimit: 10selector:matchLabels:k8s-app: kubernetes-dashboardtemplate:metadata:labels:k8s-app: kubernetes-dashboardspec:containers:- name: kubernetes-dashboardimage: k8s.gcr.io/kubernetes-dashboard-amd64:v1.8.3ports:- containerPort: 8443protocol: TCPargs:- --auto-generate-certificates# 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:portvolumeMounts:- name: kubernetes-dashboard-certsmountPath: /certs# Create on-disk volume to store exec logs- mountPath: /tmpname: tmp-volumelivenessProbe:httpGet:scheme: HTTPSpath: /port: 8443initialDelaySeconds: 30timeoutSeconds: 30volumes:- name: kubernetes-dashboard-certssecret:secretName: kubernetes-dashboard-certs- name: tmp-volumeemptyDir: {}serviceAccountName: kubernetes-dashboard# Comment the following tolerations if Dashboard must not be deployed on mastertolerations:- key: node-role.kubernetes.io/mastereffect: NoSchedule
---
# ------------------- Dashboard Service ------------------- #
kind: Service
apiVersion: v1
metadata:labels:k8s-app: kubernetes-dashboardname: kubernetes-dashboardnamespace: kube-system
spec:ports:- port: 443targetPort: 8443selector:k8s-app: kubernetes-dashboard

可以看到该文件创建了dashboard所需的相关资源，包括Secret、ServiceAccount、Role、RoleBinding、Deployment、Service。

其中ServiceACcount给访问pod创建了一个用户。

Secret这里创建了一个空的Secret对象，Role和RoleBinding则是kubernets的RABC鉴权机制中的两个对象，用于描述用户和资源之间的连接权限。

Deployment定义了kubernetes-dashboard的pod信息。

Service则为pod创建了一个访问的入口，由于官方采用的是kubelet proxy的方式来访问，这里不做修改，当然，也可以通过NodePort方式来进行访问dashboard。

当然，如果直接用官方提供的该文件创建dashboard，由于创建的用户kubernetes-dashboard绑定的角色为kubernetes-dashboard-minimal，由于改角色并没有访问和操作集群的权限，因此登陆dashboard的时候，会提示权限错误：“configmaps is forbidden: User "system:serviceaccount:kube-system:kubernetes-dashboard"。因此需修改RoleBinding的相关参数，绑定权限更高的角色：

kind: ClusterRoleBinding
apiVersion: rbac.authorization.k8s.io/v1beta1
metadata:name: kubernetes-dashboard
subjects:- kind: ServiceAccountname: kubernetes-dashboardnamespace: kube-system
roleRef:kind: ClusterRolename: cluster-adminapiGroup: rbac.authorization.k8s.io

4：master上通过kubernetes-dashboard.yaml文件，创建dashboard：

# kubectl create -f kubernetes-dashboard.yaml
secret "kubernetes-dashboard-certs" created
serviceaccount "kubernetes-dashboard" created
role.rbac.authorization.k8s.io "kubernetes-dashboard-minimal" created
rolebinding.rbac.authorization.k8s.io "kubernetes-dashboard-minimal" created
deployment.apps "kubernetes-dashboard" created
service "kubernetes-dashboard" created

5：稍等一会，则可以看到k8s以及创建了相关的pod和service：

# kubectl get pod --all-namespaces
# kubectl get service --all-namespaces

6：开启kubelec proxy，开放dashboard端口，以便我们可以访问ui页面。（该方法为官方推介的其中一种方法，也可以使用NodePort方式）：

# kubectl proxy --address=192.168.232.130 --accept-hosts='^*$' &

配置完之后使用http://192.168.232.130:8001/api/v1/namespaces/kube-system/services/https:kubernetes-dashboard:/proxy/#!/overview?namespace=default访问dashboard。

由于我们以及对用户做过了相应的授权和绑定，因此可以直接选择“跳过”来登陆。但该方法缺少了一些安全性，所以还是建议大家可以尽量使用token或者"用户+密码验证"的方式来登陆dashboard。