一、绪论

产生问题的原因是master节点部署Pod，导致无法启动；
问题描述：
Warning FailedScheduling 40s (x28 over 28m) default-scheduler 0/1 nodes are available: 1 node(s) had taint {node-role.kubernetes.io/master: }, that the pod didn’t tolerate.

二、情景再现

部署环境，k8s中的master节点创建Pod

• 命令kubectl run 自定义pod名字 --image=基础镜像
  示例

[root@VM-4-8-centos kubernetes]# kubectl run my-nginx --image=nginx
pod/my-nginx created

• 查看pod
  由于上面创建Pod时，未指定namespace，故默认处于default中;
  命令kubectl get pod
  
  my-nginx一直处于Ping状态；

• 查看Pod描述信息
  命令kubectl describe pod 自定义的Pod名称
  
  原因：kubeadm集群时，出于安全考虑Pod不会被调度到Master Node上，默认情况下，master打了污点，不参与工作负载；
  解决方案：手动删除master的污点；

• 查看污点信息
  命令：kubectl get no -o yaml | grep taint -A 5
  

三、解决方案

• 删除master节点污点
  命令kubectl taint nodes --all node-role.kubernetes.io/master-
  结果如下：

 [root@VM-4-8-centos kubernetes]# kubectl taint nodes --all node-role.kubernetes.io/master-
node/vm-4-8-centos untainted

再次查看Pod状态，已经Running

• 查看Pod描述信息
  着重点Events：

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
  ----     ------            ----                ----               -------
  //之前Ping事件
  Warning  FailedScheduling  69s (x36 over 36m)  default-scheduler  0/1 nodes are available: 1 node(s) had taint {node-role.kubernetes.io/master: }, that the pod didn't tolerate.
 //删除污点之后，执行事件
  Normal   Pulling           44s                 kubelet            Pulling image "nginx"
  Normal   Pulled            39s                 kubelet            Successfully pulled image "nginx" in 5.61441699s
  Normal   Created           39s                 kubelet            Created container my-nginx
  Normal   Started           38s                 kubelet            Started container my-nginx

• 再次开启master节点污点
  命令kubectl taint nodes k8s node-role.kubernetes.io/master=true:NoSchedule