一 下载对应插件的yaml

kubernetes 第三方对应插件都在对应版本的这个目录下

https://github.com/kubernetes/kubernetes/tree/master/cluster/addons

CoreDNS给出了标准的deployment配置， coredns.yaml.sed

vim  coredns.yaml.sed
# Warning: This is a file generated from the base underscore template file: coredns.yaml.base

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 10.254.0.0/16  {      #着个前面domian变量需更改 和IP段
            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: 10.254.0.2 #clusterIP需要更改
  ports:
  - name: dns
    port: 53
    protocol: UDP
  - name: dns-tcp
    port: 53
    protocol: TCP

配置文件中

kubernetes $DNS_DOMAIN in-addr.arpa ip6.arpa { 更改为：

kubernetes cluster.local 10.254.0.0/16 { #着个前面domian变量需更改 和IP段

clusterIP: $DNS_SERVER_IP 更改为：

clusterIP: 10.254.0.2

#这个地方需要改成和kubelet中配置的一样--cluster-dns=10.254.0.2

2 使用kubectl创建下

kubectl create -f coredns.yaml.sed

3 验证

kubectl get all --all-namespaces
NAMESPACE     NAME                                           READY     STATUS    RESTARTS   AGE
kube-system   pod/coredns-77c989547b-4jjn8                   1/1       Running   0          27m
kube-system   pod/coredns-77c989547b-p299x                   1/1       Running   0          27m

NAMESPACE     NAME                 TYPE        CLUSTER-IP   EXTERNAL-IP   PORT(S)         AGE
default       service/kubernetes   ClusterIP   10.254.0.1   <none>        443/TCP         3d
kube-system   service/coredns       ClusterIP   10.254.0.2   <none>        53/UDP,53/TCP   27m

NAMESPACE     NAME                         DESIRED   CURRENT   READY     UP-TO-DATE   AVAILABLE   NODE SELECTOR   AG
E
NAMESPACE     NAME                                      DESIRED   CURRENT   UP-TO-DATE   AVAILABLE   AGE
kube-system   deployment.apps/coredns                   2         2         2            2           27m

NAMESPACE     NAME                                                 DESIRED   CURRENT   READY     AGE
kube-system   replicaset.apps/coredns-77c989547b                   2         2         2         27m

4 dns解析验证

创建busybox.yaml

vim busybox.yaml
apiVersion: v1
kind: Pod
metadata:
  name: busybox
  namespace: default
spec:
  containers:
  - name: busybox
    image: busybox #新的busybox有问题、使用下面的镜像
    image: docker.io/azukiapp/dig
    command:
      - sleep
      - "3600"
    imagePullPolicy: IfNotPresent
  restartPolicy: Always

创建service

kubectl create -f busybox.yaml

验证DNS解析

kubectl exec -it busybox -- nslookup kubernetes.default
Server:    10.254.0.2
Address 1: 10.254.0.2 coredns.kube-system.svc.cluster.local

Name:      kubernetes.default
Address 1: 10.254.0.1 kubernetes.default.svc.cluster.local

kubectl exec -it busybox -- nslookup kubernetes-dashboard.kube-system 点后面指定kubernetes的namespace

Server: 10.254.0.2

Address 1: 10.254.0.2 coredns.kube-system.svc.cluster.local

Name: kubernetes-dashboard.kube-system

Address 1: 10.254.246.240 kubernetes-dashboard.kube-system.svc.cluster.local

coredns 配置自己内部dns

增加:upstream和下面域的配置文件

配置文件更改如下：

Corefile: |

.:53 {

    errors

    health

    ready

    kubernetes cluster.local 10.254.0.0/16 in-addr.arpa ip6.arpa {

        pods insecure

        upstream

        fallthrough in-addr.arpa ip6.arpa

        ttl 30

    }

    prometheus :9153

    forward . /etc/resolv.conf

    cache 30

    loop

    reload

    loadbalance

}

docker.hc360.com:53 {

    errors

    \#kubernetes $DNS\_DOMAIN in-addr.arpa ip6.arpa {

    forward . 10.7.3.22

    cache 30

}

hc360.com:53 {

    errors

    \#kubernetes $DNS\_DOMAIN in-addr.arpa ip6.arpa {

    forward . 10.7.3.22

    cache 30

}