经过前几篇的文章，我们通过二进制方式部署的k8s集群，差不多所有的组件都部署好了，接下来就差我们的网络插件和dns了，在这里我们的网络插件使用calico，dns解析使用coredns。

**网络插件安装
**

PS：该步骤只需要在node1上执行即可，即master节点执行。

下面的地址是官网地址，感兴趣的可以看下介绍：

https://projectcalico.docs.tigera.io/getting-started/kubernetes/self-managed-onprem/onpremises

如果你的节点数量是50以下，选择以下命令下载：

[root@node1 ~]# curl https://projectcalico.docs.tigera.io/manifests/calico.yaml -O
[root@node1 ~]# ls calico.yaml 
calico.yaml
[root@node1 ~]#

如果是50个节点以上，请执行如下命令下载：

[root@node1 ~]# curl https://projectcalico.docs.tigera.io/manifests/calico-typha.yaml -o calico.yaml
[root@node1 ~]# ls calico.yaml 
calico.yaml
[root@node1 ~]#

修改IP自动发现：

为啥要修改呢？因为如果当你的服务器上存在多个IP地址，或者说有很多虚拟网卡的时候，他有时候就会获取到错误的IP地址，所以要进行如下配置。

[root@node1 ~]# vim calico.yaml  # 有两个配置需要修改
# 修改前
- name: IP
  value: "autodetect"
  
# 修改成
- name: IP
  valueFrom:
    fieldRef:
      fieldPath: status.hostIP
      
# 修改前是被注释的状态
# - name: CALICO_IPV4POOL_CIDR
#   value: "192.168.0.0/16"
# 修改成
- name: CALICO_IPV4POOL_CIDR
  value: "10.200.0.0/16"
[root@node1 ~]# 

让其生效：

[root@node1 ~]# kubectl apply -f calico.yaml

等几分钟之后，查看状态如下，如果status不是running，可能是镜像还没有下载完，再稍等几分钟就行了。

[root@node1 ~]# kubectl get nodes
NAME    STATUS   ROLES    AGE   VERSION
node2   Ready    <none>   15h   v1.20.2
node3   Ready    <none>   15h   v1.20.2
[root@node1 ~]#
[root@node1 ~]# kubectl get pod -n kube-system
NAME                                       READY   STATUS    RESTARTS   AGE
calico-kube-controllers-858c9597c8-6gzd5   1/1     Running   0          43m
calico-node-6k479                          1/1     Running   0          43m
calico-node-bnbxx                          1/1     Running   0          43m
nginx-proxy-node3                          1/1     Running   1          15h
[root@node1 ~]# 

DNS解析

设置nds的cluster-ip地址：

# 这个IP要和之前安装apiserver的时候配置中的一个哈
[root@node1 ~]# COREDNS_CLUSTER_IP=10.233.0.10

创建coredns.yaml的配置：

# 以下配置文件不需要修改任何信息
[root@node1 ~]# vim coredns.yaml 
---
apiVersion: v1
kind: ConfigMap
metadata:
  name: coredns
  namespace: kube-system
  labels:
      addonmanager.kubernetes.io/mode: EnsureExists
data:
  Corefile: |
    .:53 {
        errors
        health {
            lameduck 5s
        }
        ready
        kubernetes cluster.local in-addr.arpa ip6.arpa {
          pods insecure
          fallthrough in-addr.arpa ip6.arpa
        }
        prometheus :9153
        forward . /etc/resolv.conf {
          prefer_udp
        }
        cache 30
        loop
        reload
        loadbalance
    }
---
apiVersion: v1
kind: ServiceAccount
metadata:
  name: coredns
  namespace: kube-system
  labels:
    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
  - apiGroups:
      - ""
    resources:
      - nodes
    verbs:
      - get
---
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: Service
metadata:
  name: coredns
  namespace: kube-system
  labels:
    k8s-app: kube-dns
    kubernetes.io/name: "coredns"
    addonmanager.kubernetes.io/mode: Reconcile
  annotations:
    prometheus.io/port: "9153"
    prometheus.io/scrape: "true"
spec:
  selector:
    k8s-app: kube-dns
  clusterIP: ${COREDNS_CLUSTER_IP}
  ports:
    - name: dns
      port: 53
      protocol: UDP
    - name: dns-tcp
      port: 53
      protocol: TCP
    - name: metrics
      port: 9153
      protocol: TCP
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: "coredns"
  namespace: kube-system
  labels:
    k8s-app: "kube-dns"
    addonmanager.kubernetes.io/mode: Reconcile
    kubernetes.io/name: "coredns"
spec:
  replicas: 2
  strategy:
    type: RollingUpdate
    rollingUpdate:
      maxUnavailable: 0
      maxSurge: 10%
  selector:
    matchLabels:
      k8s-app: kube-dns
  template:
    metadata:
      labels:
        k8s-app: kube-dns
      annotations:
        seccomp.security.alpha.kubernetes.io/pod: 'runtime/default'
    spec:
      priorityClassName: system-cluster-critical
      nodeSelector:
        kubernetes.io/os: linux
      serviceAccountName: coredns
      tolerations:
        - key: node-role.kubernetes.io/master
          effect: NoSchedule
      affinity:
        podAntiAffinity:
          requiredDuringSchedulingIgnoredDuringExecution:
          - topologyKey: "kubernetes.io/hostname"
            labelSelector:
              matchLabels:
                k8s-app: kube-dns
        nodeAffinity:
          preferredDuringSchedulingIgnoredDuringExecution:
          - weight: 100
            preference:
              matchExpressions:
              - key: node-role.kubernetes.io/master
                operator: In
                values:
                - ""
      containers:
      - name: coredns
        image: "docker.io/coredns/coredns:1.6.7"
        imagePullPolicy: IfNotPresent
        resources:
          # TODO: Set memory limits when we've profiled the container for large
          # clusters, then set request = limit to keep this container in
          # guaranteed class. Currently, this container falls into the
          # "burstable" category so the kubelet doesn't backoff from restarting it.
          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
        - containerPort: 9153
          name: metrics
          protocol: TCP
        securityContext:
          allowPrivilegeEscalation: false
          capabilities:
            add:
            - NET_BIND_SERVICE
            drop:
            - all
          readOnlyRootFilesystem: true
        livenessProbe:
          httpGet:
            path: /health
            port: 8080
            scheme: HTTP
          timeoutSeconds: 5
          successThreshold: 1
          failureThreshold: 10
        readinessProbe:
          httpGet:
            path: /ready
            port: 8181
            scheme: HTTP
          timeoutSeconds: 5
          successThreshold: 1
          failureThreshold: 10
      dnsPolicy: Default
      volumes:
        - name: config-volume
          configMap:
            name: coredns
            items:
            - key: Corefile
              path: Corefile


[root@node1 ~]# sed -i "s/\${COREDNS_CLUSTER_IP}/${COREDNS_CLUSTER_IP}/g" coredns.yaml
[root@node1 ~]#

使其生效：

[root@node1 ~]# kubectl apply -f coredns.yaml

部署NodeLocal DNSCache：

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