K8s如何部署coredns

本篇内容介绍了"K8s如何部署coredns"的有关知识，在实际案例的操作过程中，不少人都会遇到这样的困境，接下来就让小编带领大家学习一下如何处理这些情况吧！希望大家仔细阅读，能够学有所成！

为什么需要DNS？

通常k8s集群内服务发现是通过dns实现的，可以使用kubedns或者coredns实现

DNS通常指定的namespace为 kube-system 在查看是需要指定namespace查看

编辑coredns yaml文件

# cat coredns.yaml apiVersion: v1kind: ServiceAccountmetadata:  name: coredns  namespace: kube-system  labels:      kubernetes.io/cluster-service: "true"      addonmanager.kubernetes.io/mode: Reconcile---apiVersion: rbac.authorization.k8s.io/v1kind: ClusterRolemetadata:  labels:    kubernetes.io/bootstrapping: rbac-defaults    addonmanager.kubernetes.io/mode: Reconcile  name: system:corednsrules:- apiGroups:  - ""  resources:  - endpoints  - services  - pods  - namespaces  verbs:  - list  - watch---apiVersion: rbac.authorization.k8s.io/v1kind: ClusterRoleBindingmetadata:  annotations:    rbac.authorization.kubernetes.io/autoupdate: "true"  labels:    kubernetes.io/bootstrapping: rbac-defaults    addonmanager.kubernetes.io/mode: EnsureExists  name: system:corednsroleRef:  apiGroup: rbac.authorization.k8s.io  kind: ClusterRole  name: system:corednssubjects:- kind: ServiceAccount  name: coredns  namespace: kube-system---apiVersion: v1kind: ConfigMapmetadata:  name: coredns  namespace: kube-system  labels:      addonmanager.kubernetes.io/mode: EnsureExistsdata:  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/v1beta1kind: Deploymentmetadata:  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: v1kind: Servicemetadata:  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: 10.1.0.2  ports:  - name: dns    port: 53    protocol: UDP  - name: dns-tcp    port: 53    protocol: TCP

创建deployment

kubectl create -f coredns.yaml

查看相关信息

 kubectl get svc -n kube-systemkubectl get pod -o wide -n kube-system

注意创建coredns deployment yaml文件里面指定的集群IP是根据K8s进群规划指定。

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