maintain a node

Node taint tolerant

// taint节点，阻止新的pod上来
kubectl taint nodes node08 dedicated=maintaining:NoSchedule
// label节点，只允许指定的pod上来
kubectl label nodes node08 hyper/nodetype=maintaining

// 然后在Pod定义中加入如下annotation：
```
annotations:
      scheduler.alpha.kubernetes.io/tolerations: '[{"key":"dedicated", "value":"maintaining"}]'
      scheduler.alpha.kubernetes.io/affinity: >
        {
          "nodeAffinity": {
            "requiredDuringSchedulingIgnoredDuringExecution": {
              "nodeSelectorTerms": [
                {
                  "matchExpressions": [
                    {
                      "key": "hyper/nodetype",
                      "operator": "In",
                      "values": ["maintaining"]
                    }
                  ]
                }
              ]
            }
          }
        }
        ```