执行kubectl get node命令，可以看到如下结果：
[root@APP-SERVER-75 ~]# kubectl get node
NAME STATUS ROLES AGE VERSION
app-server-75 Ready master 18h v1.16.3
app-server-76 Ready master 18h v1.16.3
app-server-77 Ready <none> 17h v1.16.3
app-server-78 Ready <none> 17h v1.16.3
app-server-86 Ready <none> 17h v1.16.3
app-server-87 Ready <none> 17h v1.16.3
app-server-88 Ready <none> 17h v1.16.3
再执行：kubectl describe node node1
Name: app-server-75
Roles: master
Labels: beta.kubernetes.io/arch=amd64
beta.kubernetes.io/os=linux
kubernetes.io/arch=amd64
kubernetes.io/hostname=app-server-75
kubernetes.io/os=linux
node-role.kubernetes.io/master=
Annotations: flannel.alpha.coreos.com/backend-data: {"VtepMAC":"26:bd:ce:f0:93:41"}
flannel.alpha.coreos.com/backend-type: vxlan
flannel.alpha.coreos.com/kube-subnet-manager: true
flannel.alpha.coreos.com/public-ip: 192.9.202.75
kubeadm.alpha.kubernetes.io/cri-socket: /var/run/dockershim.sock
node.alpha.kubernetes.io/ttl: 0
volumes.kubernetes.io/controller-managed-attach-detach: true
CreationTimestamp: Mon, 02 Dec 2019 15:36:44 +0800
需要将node标签加回去，则要执行：
kubectl label nodes node1 node-role.kubernetes.io/node=
需要将node标签删除，则要执行：
kubectl label nodes node1 node-role.kubernetes.io/node-