记录一次调查OpenEuler上部署K8s，CoreDNS组件一直 CrashLoopBackOff ，describe 时 Back-off restarting failed container

详细过程不赘述了。百度了很多办法都不可用，然后尝试重装k8s 好多次也不管用。

最后解决。

kubectl edit deployment coredns -n kube-system

apiVersion: apps/v1
kind: Deployment
metadata:
  annotations:
    deployment.kubernetes.io/revision: "2"
  creationTimestamp: "2023-08-14T06:04:16Z"
  generation: 2
  labels:
    k8s-app: kube-dns
  name: coredns
  namespace: kube-system
  resourceVersion: "1505"
  uid: 18c027ac-0745-4418-afe5-522ee1e1f369
spec:
  progressDeadlineSeconds: 600
  replicas: 2
  revisionHistoryLimit: 10
  selector:
    matchLabels:
      k8s-app: kube-dns
  strategy:
    rollingUpdate:
      maxSurge: 25%
      maxUnavailable: 1
    type: RollingUpdate
  template:
    metadata:
      creationTimestamp: null
      labels:
        k8s-app: kube-dns
    spec:
      containers:
      - args:
        - -conf
        - /etc/coredns/Corefile
        command:
        - /bin/bash
        - -ce
        - tail -f /dev/null
        image: registry.aliyuncs.com/google_containers/coredns/coredns:v1.8.0
        imagePullPolicy: IfNotPresent
        livenessProbe:
          failureThreshold: 5
          httpGet:
            path: /health
            port: 8080
            scheme: HTTP
          initialDelaySeconds: 60
          periodSeconds: 10
          successThreshold: 1
          timeoutSeconds: 5
        name: coredns
        ports:
        - containerPort: 53
          name: dns
          protocol: UDP
        - containerPort: 53
          name: dns-tcp
          protocol: TCP
        - containerPort: 9153
          name: metrics
          protocol: TCP
        readinessProbe:
          failureThreshold: 3
          httpGet:
            path: /ready
            port: 8181
            scheme: HTTP
          periodSeconds: 10
          successThreshold: 1
          timeoutSeconds: 1
        resources:
          limits:
            memory: 170Mi
          requests:
            cpu: 100m
            memory: 70Mi
        securityContext:
          allowPrivilegeEscalation: false
          capabilities:
            add:
            - NET_BIND_SERVICE
            drop:
            - all
          readOnlyRootFilesystem: true
        terminationMessagePath: /dev/termination-log
        terminationMessagePolicy: File
        volumeMounts:
        - mountPath: /etc/coredns
          name: config-volume
          readOnly: true
      dnsPolicy: Default
      nodeSelector:
        kubernetes.io/os: linux
      priorityClassName: system-cluster-critical
      restartPolicy: Always
      schedulerName: default-scheduler
      securityContext: {}
      serviceAccount: coredns
      serviceAccountName: coredns
      terminationGracePeriodSeconds: 30
      tolerations:
      - key: CriticalAddonsOnly
        operator: Exists
      - effect: NoSchedule
        key: node-role.kubernetes.io/master
      - effect: NoSchedule
        key: node-role.kubernetes.io/control-plane
      volumes:
      - configMap:
          defaultMode: 420
          items:
          - key: Corefile
            path: Corefile
          name: coredns
        name: config-volume
status:
  conditions:
  - lastTransitionTime: "2023-08-14T06:04:33Z"
    lastUpdateTime: "2023-08-14T06:04:33Z"
    message: Deployment does not have minimum availability.
    reason: MinimumReplicasUnavailable
    status: "False"
    type: Available
  - lastTransitionTime: "2023-08-14T06:15:18Z"
    lastUpdateTime: "2023-08-14T06:15:19Z"
    message: ReplicaSet "coredns-57d966b595" is progressing.
    reason: ReplicaSetUpdated
    status: "True"
    type: Progressing
  observedGeneration: 2
  replicas: 3
  unavailableReplicas: 3
  updatedReplicas: 2