在已有k8s云平台中误删除node节点，然后将误删除的节点添加进集群中。如果是一台新服务器必须还要安装docker和k8s基础组件。

1.查看节点数和删除node节点（master节点）

[root@k8s01 ~]# kubectl  get nodes
NAME    STATUS   ROLES    AGE   VERSION
k8s01   Ready    master   40d   v1.15.3
k8s02   Ready    <none>   40d   v1.15.3
k8s03   Ready    <none>   40d   v1.15.3

[root@k8s01 ~]# kubectl  delete nodes k8s03
node "k8s03" deleted
[root@k8s01 ~]# kubectl  get nodes
NAME    STATUS   ROLES    AGE   VERSION
k8s01   Ready    master   40d   v1.15.3
k8s02   Ready    <none>   40d   v1.15.3
[root@k8s01 ~]#

2.在被删除的node节点清空集群信息

[root@k8s03 ~]# kubeadm reset
[reset] WARNING: Changes made to this host by 'kubeadm init' or 'kubeadm join' will be reverted.
[reset] Are you sure you want to proceed? [y/N]: y
[preflight] Running pre-flight checks
W1017 15:43:41.491522    3010 removeetcdmember.go:79] [reset] No kubeadm config, using etcd pod spec to get data directory
[reset] No etcd config found. Assuming external etcd
[reset] Please, manually reset etcd to prevent further issues
[reset] Stopping the kubelet service
[reset] Unmounting mounted directories in "/var/lib/kubelet"
[reset] Deleting contents of config directories: [/etc/kubernetes/manifests /etc/kubernetes/pki]
[reset] Deleting files: [/etc/kubernetes/admin.conf /etc/kubernetes/kubelet.conf /etc/kubernetes/bootstrap-kubelet.conf /etc/kubernetes/controller-manager.conf /etc/kubernetes/scheduler.conf]
[reset] Deleting contents of stateful directories: [/var/lib/kubelet /etc/cni/net.d /var/lib/dockershim /var/run/kubernetes]

The reset process does not reset or clean up iptables rules or IPVS tables.
If you wish to reset iptables, you must do so manually.
For example:
iptables -F && iptables -t nat -F && iptables -t mangle -F && iptables -X

If your cluster was setup to utilize IPVS, run ipvsadm --clear (or similar)
to reset your system's IPVS tables.

The reset process does not clean your kubeconfig files and you must remove them manually.
Please, check the contents of the $HOME/.kube/config file.
[root@k8s03 ~]# 

3.在master节点查看集群的token值

[root@k8s01 ~]# kubeadm token create --print-join-command
kubeadm join 192.168.54.128:6443 --token mg4o13.4ilr1oi605tj850w     --discovery-token-ca-cert-hash sha256:363b5b8525ddb86f4dc157f059e40c864223add26ef53d0cfc9becc3cbae8ad3
[root@k8s01 ~]#

4.将node节点重新添加到k8s集群中

[root@k8s03 ~]# kubeadm join 192.168.54.128:6443 --token mg4o13.4ilr1oi605tj850w     --discovery-token-ca-cert-hash sha256:363b5b8525ddb86f4dc157f059e40c864223add26ef53d0cfc9becc3cbae8ad3
[preflight] Running pre-flight checks
 [WARNING IsDockerSystemdCheck]: detected "cgroupfs" as the Docker cgroup driver. The recommended driver is "systemd". Please follow the guide at https://kubernetes.io/docs/setup/cri/
 [WARNING SystemVerification]: this Docker version is not on the list of validated versions: 19.03.2. Latest validated version: 18.09
[preflight] Reading configuration from the cluster...
[preflight] FYI: You can look at this config file with 'kubectl -n kube-system get cm kubeadm-config -oyaml'
[kubelet-start] Downloading configuration for the kubelet from the "kubelet-config-1.15" ConfigMap in the kube-system namespace
[kubelet-start] Writing kubelet configuration to file "/var/lib/kubelet/config.yaml"
[kubelet-start] Writing kubelet environment file with flags to file "/var/lib/kubelet/kubeadm-flags.env"
[kubelet-start] Activating the kubelet service
[kubelet-start] Waiting for the kubelet to perform the TLS Bootstrap...

This node has joined the cluster:
* Certificate signing request was sent to apiserver and a response was received.
* The Kubelet was informed of the new secure connection details.

Run 'kubectl get nodes' on the control-plane to see this node join the cluster.

[root@k8s03 ~]# 

5.查看整个集群状态

[root@k8s01 ~]# kubectl  get nodes
NAME    STATUS   ROLES    AGE   VERSION
k8s01   Ready    master   40d   v1.15.3
k8s02   Ready    <none>   40d   v1.15.3
k8s03   Ready    <none>   41s   v1.15.3
[root@k8s01 ~]#