k8s创建pod并运行时：
[root@master ~]# kubectl run nginx --image=nginx kubectl run --generator=deployment/apps.v1beta1 is DEPRECATED and will be removed in a future version. Use kubectl create instead. deployment.apps/nginx created查看pods：出现下面报错，一直无法执行成功。
[root@master ~]# kubectl get pods NAME READY STATUS RESTARTS AGE nginx-dbddb74b8-h4mwk 0/1 ImagePullBackOff 0 2m56s调查错误原因，在 master 服务器上面执行命令: kubectl describe pod ，查看nginx实例的报错信息：
[root@master ~]# kubectl describe pod nginx-dbddb74b8-597r8 Name: nginx-dbddb74b8-597r8 Namespace: default Priority: 0 PriorityClassName: <none> Node: 14.0.0.55/14.0.0.55 Start Time: Thu, 08 Oct 2020 01:19:08 +0800 Labels: pod-template-hash=dbddb74b8 run=nginx Annotations: <none> Status: Pending IP: 172.17.41.3 Controlled By: ReplicaSet/nginx-dbddb74b8 Containers: nginx: Container ID: Image: nginx Image ID: Port: <none> Host Port: <none> State: Waiting Reason: ImagePullBackOff Ready: False Restart Count: 0 Environment: <none> Mounts: /var/run/secrets/kubernetes.io/serviceaccount from default-token-x5xpc (ro) Conditions: Type Status Initialized True Ready False ContainersReady False PodScheduled True Volumes: default-token-x5xpc: Type: Secret (a volume populated by a Secret) SecretName: default-token-x5xpc 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 Scheduled 93s default-scheduler Successfully assigned default/nginx-dbddb74b8-597r8 to 14.0.0.55 Warning Failed 19s kubelet, 14.0.0.55 Failed to pull image "nginx": rpc error: code = Canceled desc = context canceled Warning Failed 19s kubelet, 14.0.0.55 Error: ErrImagePull Normal BackOff 18s kubelet, 14.0.0.55 Back-off pulling image "nginx" Warning Failed 18s kubelet, 14.0.0.55 Error: ImagePullBackOff Normal Pulling 5s (x2 over 92s) kubelet, 14.0.0.55 pulling image "nginx"可以看到报错信息：
Warning Failed 19s kubelet, 14.0.0.55 Failed to pull image "nginx": rpc error: code = Canceled desc = context canceled原因是服务器忘记了给docker配置国内镜像：
[root@node01 cfg]# tee /etc/docker/daemon.json <<-'EOF' > { > "registry-mirrors": ["https://8i185852.mirror.aliyuncs.com"] > } > EOF配置上国内镜像，然后执行：
[root@node01 cfg]# systemctl daemon-reload [root@node01 cfg]# systemctl restart docker就可以了：
[root@master ~]# kubectl get cs NAME STATUS MESSAGE ERROR scheduler Healthy ok controller-manager Healthy ok etcd-0 Healthy {"health":"true"} etcd-2 Healthy {"health":"true"} etcd-1 Healthy {"health":"true"} [root@master ~]# kubectl get pods NAME READY STATUS RESTARTS AGE nginx-dbddb74b8-t45hv 1/1 Running 0 34s搞定。 （或者你直接 systemctl daemon-reload systemctl restart docker）
