1.背景

运行kubectl get all出现pod status为ContainerCreating

$ kubectl get all
NAME                                    READY   STATUS              RESTARTS   AGE
pod/mysql-deployment-6ccf56667c-9b2gg   0/1     ContainerCreating   0          127m
NAME                 TYPE        CLUSTER-IP      EXTERNAL-IP   PORT(S)          AGE
service/kubernetes   ClusterIP   10.96.0.1       <none>        443/TCP          160m
service/mysql        NodePort    10.101.39.106   <none>        3306:30007/TCP   130m
NAME                               READY   UP-TO-DATE   AVAILABLE   AGE
deployment.apps/mysql-deployment   0/1     1            0           130m
NAME                                          DESIRED   CURRENT   READY   AGE
replicaset.apps/mysql-deployment-6ccf56667c   1         1         0       127m

2.分析过程

使用kubectl describe pod < podname >查看pod的情景kubectl describe pod mysql-deployment-6ccf56667c-9b2gg

$ kubectl describe pod mysql-deployment-6ccf56667c-9b2gg
Name:           mysql-deployment-6ccf56667c-9b2gg
Namespace:      default
Priority:       0
Node:           kmaster1/192.168.0.165
Start Time:     Fri, 28 Oct 2022 18:07:49 -0400
Labels:         app=mysql
                pod-template-hash=6ccf56667c
Annotations:    <none>
Status:         Pending
IP:             
IPs:            <none>
Controlled By:  ReplicaSet/mysql-deployment-6ccf56667c
Containers:
  mysql:
    Container ID:   
    Image:          mysql:latest
    Image ID:       
    Port:           3306/TCP
    Host Port:      0/TCP
    State:          Waiting
      Reason:       ContainerCreating
    Ready:          False
    Restart Count:  0
    Environment:
      MYSQL_ROOT_PASSWORD:  <set to the key 'password' in secret 'mysql-root-pass'>  Optional: false
      MYSQL_DATABASE:       <set to the key 'database' in secret 'mysql-db-url'>     Optional: false
      MYSQL_USER:           <set to the key 'username' in secret 'mysql-user-pass'>  Optional: false
      MYSQL_PASSWORD:       <set to the key 'password' in secret 'mysql-user-pass'>  Optional: false
    Mounts:
      /var/lib/mysql from mysql-pv (rw)
      /var/run/secrets/kubernetes.io/serviceaccount from kube-api-access-hjf5p (ro)
Conditions:
  Type              Status
  Initialized       True 
  Ready             False 
  ContainersReady   False 
  PodScheduled      True 
Volumes:
  mysql-pv:
    Type:       PersistentVolumeClaim (a reference to a PersistentVolumeClaim in the same namespace)
    ClaimName:  mysql-pv-claim
    ReadOnly:   false
  kube-api-access-hjf5p:
    Type:                    Projected (a volume that contains injected data from multiple sources)
    TokenExpirationSeconds:  3607
    ConfigMapName:           kube-root-ca.crt
    ConfigMapOptional:       <nil>
    DownwardAPI:             true
QoS Class:                   BestEffort
Node-Selectors:              <none>
Tolerations:                 node.kubernetes.io/not-ready:NoExecute op=Exists for 300s
                             node.kubernetes.io/unreachable:NoExecute op=Exists for 300s
Events:
  Type     Reason                  Age                      From     Message
  ----     ------                  ----                     ----     -------
  Normal   SandboxChanged          27m (x1921 over 147m)    kubelet  Pod sandbox changed, it will be killed and re-created.
  Warning  FailedCreatePodSandBox  2m38s (x2296 over 147m)  kubelet  (combined from similar events): Failed to create pod sandbox: rpc error: code = Unknown desc = failed to set up sandbox container "f313bae848e45c78b7891244005cbef658cc3004008b3993de9e7a716447bf9d" network for pod "mysql-deployment-6ccf56667c-9b2gg": networkPlugin cni failed to set up pod "mysql-deployment-6ccf56667c-9b2gg_default" network: open /run/flannel/subnet.env: no such file or directory

最后可以看到错误原因是open /run/flannel/subnet.env: no such file or directory

3.解决方案

1. 执行kubectl apply -f https://raw.githubusercontent.com/flannel-io/flannel/master/Documentation/kube-flannel.yml命令

2. 在/run/flannel/subnet.env中添加

   FLANNEL_NETWORK=10.244.0.0/16
   FLANNEL_SUBNET=10.244.0.1/24
   FLANNEL_MTU=1450
   FLANNEL_IPMASQ=true

3. 执行下面的命令：

   systemctl stop kubelet
   systemctl stop docker
   iptables --flush
   iptables -tnat --flush
   systemctl start kubelet
   systemctl start docker

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