Today, when learning kubernetes, I started an msyql service and ran the command

[root@liuxuchong kubernetes]# kubectl create -f mysql-rc.yaml
replicationcontroller "mysql" created
[root@liuxuchong kubernetes]# kubectl get all
NAME       DESIRED   CURRENT   READY     AGE
rc/mysql   1         1         0         6m

NAME             CLUSTER-IP   EXTERNAL-IP   PORT(S)   AGE
svc/kubernetes   10.254.0.1   <none>        443/TCP   10m

NAME             READY     STATUS              RESTARTS   AGE
po/mysql-f7df5   0/1       ContainerCreating   0          6m

It can be seen that rc has no ready, and pod always shows ContainerCreating
Show pod details

[root@liuxuchong ca]# kubectl describe pod mysql-f7df5
Name:       mysql-f7df5
Namespace:  default
Node:       127.0.0.1/127.0.0.1
Start Time: Wed, 15 May 2019 11:56:38 +0800
Labels:     app=mysql
Status:     Pending
IP:     
Controllers:    ReplicationController/mysql
Containers:
  mysql:
    Container ID:   
    Image:      mysql
    Image ID:       
    Port:       3306/TCP
    State:      Waiting
      Reason:       ContainerCreating
    Ready:      False
    Restart Count:  0
    Volume Mounts:  <none>
    Environment Variables:
      MYSQL_ROOT_PASSWORD:  123456
Conditions:
  Type      Status
  Initialized   True 
  Ready     False 
  PodScheduled  True 
No volumes.
QoS Class:  BestEffort
Tolerations:    <none>
Events:
  FirstSeen LastSeen    Count   From            SubObjectPath   Type        Reason      Message
  --------- --------    -----   ----            -------------   --------    ------      -------
  5m        5m      1   {default-scheduler }            Normal      Scheduled   Successfully assigned mysql-f7df5 to 127.0.0.1
  5m        2m      5   {kubelet 127.0.0.1}         Warning     FailedSync  Error syncing pod, skipping: failed to "StartContainer" for "POD" with ErrImagePull: "image pull faileredhat.com/rhel7/pod-infrastructure:latest, this may be because there are no credentials on this request.  details: (open /etc/docker/certs.d/registry.access.redhat.com/redhat-ca.crt: no such file or directory)"

  4m    5s  19  {kubelet 127.0.0.1}     Warning FailedSync  Error syncing pod, skipping: failed to "StartContainer" for "POD" with ImagePullBackOff: "Back-off pulling image \"registry.access.redastructure:latest\""

I saw two warnings. The first one was that the pull image request failed. The meaning in parentheses was that there was no such directory. I manually checked and found that there was such a directory. On the Internet, I said to install RHSM, yum install rhsm-y. I found that the problem still hasn't been solved. So I thought that the pull image needs to access the Internet. Alibaba cloud's machines can't access the Internet, so I pulled it from foreign servers Image taken.
Check the log with the command journalctl -u kubelet -f

[root@liuxuchong kubernetes]# journalctl -u kubelet -f
-- Logs begin at Tue 2018-04-10 03:20:48 CST. --
May 15 12:02:25 liuxuchong kubelet[28192]: E0515 12:02:25.614469   28192 docker_manager.go:2159] Failed to create pod infra container: ImagePullBackOff; Skipping pod "mysql-f7df5_default(70ce53f4-76c5-11e9-963f-00163e324a1f)": Back-off pulling image "registry.access.redhat.com/rhel7/pod-infrastructure:latest"
May 15 12:02:25 liuxuchong kubelet[28192]: E0515 12:02:25.614942   28192 pod_workers.go:184] Error syncing pod 70ce53f4-76c5-11e9-963f-00163e324a1f, skipping: failed to "StartContainer" for "POD" with ImagePullBackOff: "Back-off pulling image \"registry.access.redhat.com/rhel7/pod-infrastructure:latest\""

Pull decisively (servers that can access the Internet)

docker pull registry.access.redhat.com/rhel7/pod-infrastructure:latest

Then upload it to dockerhub, the upload process will not be detailed, Baidu will not do it by itself, then pull the image on the local machine, change the name
Name it registry.access.redhat.com/rhel7/pod-infrastructure:latest
Finally, delete the original rc and pod

[root@liuxuchong ca]# kubectl get all
NAME       DESIRED   CURRENT   READY     AGE
rc/mysql   1         1         0         6m

NAME             CLUSTER-IP   EXTERNAL-IP   PORT(S)   AGE
svc/kubernetes   10.254.0.1   <none>        443/TCP   10m

NAME             READY     STATUS              RESTARTS   AGE
po/mysql-f7df5   0/1       ContainerCreating   0          6m
[root@liuxuchong ca]# kubectl delete rc mysql
replicationcontroller "mysql" deleted
[root@liuxuchong ca]# kubectl delete pod mysql-f7df5
pod "mysql-f7df5" deleted

Re create

[root@liuxuchong kubernetes]# kubectl create -f mysql-rc.yaml 
replicationcontroller "mysql" created
[root@liuxuchong kubernetes]# kubectl get rc
NAME      DESIRED   CURRENT   READY     AGE
mysql     1         1         1         7s
[root@liuxuchong kubernetes]# kubectl get pods
NAME          READY     STATUS    RESTARTS   AGE
mysql-r4kxq   1/1       Running   0          12s

pod status finally becomes Running