现象：
[root@master cluster]# kubeadm init --config=kubeadm.yml --experimental-upload-certs|tee kubeadm=init.log unknown flag: --experimental-upload-certs To see the stack trace of this error execute with --v=5 or higher
之前版本为v1.4.0时该命令正常执行
解决办法: 将–experimental-upload-certs 替换为 --upload-certs
kubeadm init --config=kubeadm.yml --upload-certs | tee kubeadm-init.log