Rancher 删除集群或主机后无法重新添加主机，一般是因为删除主机后，主机上依然有残留文件。重新添加主机后残留的文件会执行之前的操作导致无法正常运行。

docker stop $(docker ps -a -q)
docker system prune -f
docker volume rm $(docker volume ls -q)
docker rm -f $(docker ps -a -q)
rm -rf /etc/ceph \
       /etc/cni \
       /etc/kubernetes \
       /opt/cni \
       /opt/rke \
       /run/secrets/kubernetes.io \
       /run/calico \
       /run/flannel \
       /var/lib/calico \
       /var/lib/etcd \
       /var/lib/cni \
       /var/lib/kubelet
       /var/lib/rancher/rke/log \
       /var/log/containers \
       /var/log/pods \