pod状态为Back-off

查看pod状态为CrashLoopBackOff

[root@master yaml]# kubectl get pods
NAME                     READY     STATUS             RESTARTS   AGE
mysql-77b495b4fd-pjw2w   0/1       CrashLoopBackOff   5          5m

查看pod的详细信息，看到最后一行
Back-off restarting failed container

[root@master yaml]# kubectl describe pod/mysql-77b495b4fd-pjw2w
Name:           mysql-77b495b4fd-pjw2w
Namespace:      default
Node:           node2/192.168.1.100
Start Time:     Tue, 24 Jul 2018 09:56:37 +0800
Labels:         app=mysql
                pod-template-hash=3360516098
Annotations:    <none>
Status:         Running
IP:             10.244.2.90
Controlled By:  ReplicaSet/mysql-77b495b4fd
Containers:
  mysql:
    Container ID:   docker://00a667790c3ec1d07071e15f49887c0df1d06964612952775d3e2f7f40e4cffe
    Image:          mysql:5.6
    Image ID:       docker-pullable://mysql@sha256:29e32fba52c3e6708fdc8a7678287debe3554febced25ade8686a63d4409ceda
    Port:           3306/TCP
    Host Port:      0/TCP
    State:          Terminated
      Reason:       Error
      Exit Code:    1
      Started:      Tue, 24 Jul 2018 10:02:21 +0800
      Finished:     Tue, 24 Jul 2018 10:02:21 +0800
    Last State:     Terminated
      Reason:       Error
      Exit Code:    1
      Started:      Tue, 24 Jul 2018 09:59:30 +0800
      Finished:     Tue, 24 Jul 2018 09:59:30 +0800
    Ready:          False
    Restart Count:  6
    Environment:
      MYSQL_ROOT_PASSWORD:  
    Mounts:
      /var/lib/mysql from mysql-persistent-storage (rw)
      /var/run/secrets/kubernetes.io/serviceaccount from default-token-zjcdx (ro)
Conditions:
  Type           Status
  Initialized    True 
  Ready          False 
  PodScheduled   True 
Volumes:
  mysql-persistent-storage:
    Type:       PersistentVolumeClaim (a reference to a PersistentVolumeClaim in the same namespace)
    ClaimName:  mysql-pvc
    ReadOnly:   false
  default-token-zjcdx:
    Type:        Secret (a volume populated by a Secret)
    SecretName:  default-token-zjcdx
    Optional:    false
QoS Class:       BestEffort
Node-Selectors:  <none>
Tolerations:     node.kubernetes.io/not-ready:NoExecute for 300s
                 node.kubernetes.io/unreachable:NoExecute for 300s
Events:
  Type     Reason                 Age                From               Message
  ----     ------                 ----               ----               -------
  Normal   SuccessfulMountVolume  5m                 kubelet, node2     MountVolume.SetUp succeeded for volume "default-token-z
  Normal   SuccessfulMountVolume  5m                 kubelet, node2     MountVolume.SetUp succeeded for volume "mysql-pv"
  Normal   Pulling                5m                 kubelet, node2     pulling image "mysql:5.6"
  Normal   Scheduled              5m                 default-scheduler  Successfully assigned mysql-77b495b4fd-pjw2w to node2
  Normal   Pulled                 5m                 kubelet, node2     Successfully pulled image "mysql:5.6"
  Normal   Created                4m (x5 over 5m)    kubelet, node2     Created container
  Normal   Started                4m (x5 over 5m)    kubelet, node2     Started container
  Normal   Pulled                 4m (x4 over 5m)    kubelet, node2     Container image "mysql:5.6" already present on machine
  Warning  BackOff                45s (x24 over 5m)  kubelet, node2     Back-off restarting failed container 

查看pod的日志信息,得知mysql必须要指定其中一个变量

[root@master yaml]# kubectl log mysql-77b495b4fd-pjw2w
log is DEPRECATED and will be removed in a future version. Use logs instead.
error: database is uninitialized and password option is not specified 
  You need to specify one of MYSQL_ROOT_PASSWORD, MYSQL_ALLOW_EMPTY_PASSWORD and MYSQL_RANDOM_ROOT_PASSWORD