環境說明

Node-1(Master): 10.0.0.1
Node-2: 10.0.0.2
Node-3: 10.0.0.3

集群使用二進制安裝，並已部署flannel網絡插件。

kube-DNS

在進行如下的操作時，你必須已經部署好了K8S的集群，如果你還沒有這樣的集群，請參考我之前的博文。

1、在官網找到對應的yaml文件，地址為：https://github.com/kubernetes/kubernetes/tree/2f011d01fa542633184cde4bba97d006b8d06309/cluster/addons/dns/coredns , 我們修改相關配置，主要是ClusterIP的配置信息和鏡像路徑：

apiVersion: v1
kind: ServiceAccount
metadata:
  name: coredns
  namespace: kube-system
  labels:
      kubernetes.io/cluster-service: "true"
      addonmanager.kubernetes.io/mode: Reconcile
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRole
metadata:
  labels:
    kubernetes.io/bootstrapping: rbac-defaults
    addonmanager.kubernetes.io/mode: Reconcile
  name: system:coredns
rules:
- apiGroups:
  - ""
  resources:
  - endpoints
  - services
  - pods
  - namespaces
  verbs:
  - list
  - watch
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:
  annotations:
    rbac.authorization.kubernetes.io/autoupdate: "true"
  labels:
    kubernetes.io/bootstrapping: rbac-defaults
    addonmanager.kubernetes.io/mode: EnsureExists
  name: system:coredns
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: system:coredns
subjects:
- kind: ServiceAccount
  name: coredns
  namespace: kube-system
---
apiVersion: v1
kind: ConfigMap
metadata:
  name: coredns
  namespace: kube-system
  labels:
      addonmanager.kubernetes.io/mode: EnsureExists
data:
  Corefile: |
    .:53 {
        errors
        health
        kubernetes cluster.local. in-addr.arpa ip6.arpa {
            pods insecure
            upstream
            fallthrough in-addr.arpa ip6.arpa
        }
        prometheus :9153
        proxy . /etc/resolv.conf
        cache 30
    }
---
apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  name: coredns
  namespace: kube-system
  labels:
    k8s-app: coredns
    kubernetes.io/cluster-service: "true"
    addonmanager.kubernetes.io/mode: Reconcile
    kubernetes.io/name: "CoreDNS"
spec:
  replicas: 2
  strategy:
    type: RollingUpdate
    rollingUpdate:
      maxUnavailable: 1
  selector:
    matchLabels:
      k8s-app: coredns
  template:
    metadata:
      labels:
        k8s-app: coredns
    spec:
      serviceAccountName: coredns
      tolerations:
        - key: node-role.kubernetes.io/master
          effect: NoSchedule
        - key: "CriticalAddonsOnly"
          operator: "Exists"
      containers:
      - name: coredns
        image: coredns/coredns:1.0.6
        imagePullPolicy: IfNotPresent
        resources:
          limits:
            memory: 170Mi
          requests:
            cpu: 100m
            memory: 70Mi
        args: [ "-conf", "/etc/coredns/Corefile" ]
        volumeMounts:
        - name: config-volume
          mountPath: /etc/coredns
        ports:
        - containerPort: 53
          name: dns
          protocol: UDP
        - containerPort: 53
          name: dns-tcp
          protocol: TCP
        livenessProbe:
          httpGet:
            path: /health
            port: 8080
            scheme: HTTP
          initialDelaySeconds: 60
          timeoutSeconds: 5
          successThreshold: 1
          failureThreshold: 5
      dnsPolicy: Default
      volumes:
        - name: config-volume
          configMap:
            name: coredns
            items:
            - key: Corefile
              path: Corefile
---
apiVersion: v1
kind: Service
metadata:
  name: coredns
  namespace: kube-system
  labels:
    k8s-app: coredns
    kubernetes.io/cluster-service: "true"
    addonmanager.kubernetes.io/mode: Reconcile
    kubernetes.io/name: "CoreDNS"
spec:
  selector:
    k8s-app: coredns
  clusterIP: 10.222.0.100
  ports:
  - name: dns
    port: 53
    protocol: UDP
  - name: dns-tcp
    port: 53
    protocol: TCP
 

執行此yaml文件：

kubectl  create -f coredns.yaml

查看文件狀態：

[root@node-1 ~]# kubectl get pods -n kube-system
NAME                                    READY     STATUS    RESTARTS   AGE
coredns-77c989547b-2rg9h                1/1       Running   0          1h
coredns-77c989547b-cbj5h                1/1       Running   0          1h

[root@node-1 ~]# kubectl get rs -n kube-system
NAME                              DESIRED   CURRENT   READY     AGE
coredns-77c989547b                2         2         2         1h

[root@node-1 ~]# kubectl get svc -n kube-system
NAME                   TYPE        CLUSTER-IP       EXTERNAL-IP   PORT(S)         AGE
coredns                ClusterIP   10.222.0.100     <none>        53/UDP,53/TCP   1h
 

配置Dashboard

下載官方的yaml文件，執行如下命令：

kubectl apply -f https://raw.githubusercontent.com/kubernetes/dashboard/master/src/deploy/recommended/kubernetes-dashboard.yaml

只有安裝了dns服務才能使用dashboard，否則將無法找到dashboard的service。

當dashboard服務啟動後查看服務是否正常：

[root@node-1 ~]# kubectl get pod -n kube-system
NAME                                    READY     STATUS    RESTARTS   AGE
coredns-77c989547b-2rg9h                1/1       Running   0          2h
coredns-77c989547b-cbj5h                1/1       Running   0          2h
kubernetes-dashboard-7d5dcdb6d9-h66fs   1/1       Running   0          1h

[root@node-1 ~]# kubectl get svc -n kube-system
NAME                   TYPE        CLUSTER-IP       EXTERNAL-IP   PORT(S)         AGE
coredns                ClusterIP   10.222.0.100     <none>        53/UDP,53/TCP   2h
kubernetes-dashboard   ClusterIP   10.222.251.161   <none>        443/TCP         1h

使用代理，執行如下命令：

[root@node-1 ~]# kubectl proxy  --port=8001 --address=‘10.0.0.1‘ --accept-hosts=‘^.*‘
Starting to serve on 10.0.0.1:8001

在瀏覽器中輸入地址：http://10.0.0.1:8001/api/v1/namespaces/kube-system/services/https:kubernetes-dashboard:/proxy/

如果不出意外，會看到如下界面：

按照此提示創建用戶 https://github.com/kubernetes/dashboard/wiki/Creating-sample-user

之後獲取token,使用token登錄：

kubectl describe secret -n kube-system `kubectl get secret -n kube-system |grep admin-user |awk ‘{print $1}‘`

也可以通過master節點登錄，訪問此地址：https://10.0.0.1:6443/api/v1/namespaces/kube-system/services/https:kubernetes-dashboard:/proxy/

登錄成功後顯示主界面：

Kubernetes Dashboard 與DNS部署