k8集群未启动，报错信息如下
The connection to the server 192.168.37.201:6443 was refused - did you specify the right host or port?
首先查看systemctl status kubelet.service，未运行；重启systemctl restart kubelet.service，仍然有问题
然后查看kubelet的日志，journalctl -xe -u kubelet
failed to run Kubelet: Running with swap on is not supported, please disable swap! or set --fail-swap-on flag to false
可知是swap未关闭，查看swap的运行状态cat /proc/swaps 检查果然swap是否被关闭
解决如下：
关闭swap，集群重启后不生效
swapoff -a
修改/etc/fstab 永久关闭swap
cp -p /etc/fstab /etc/fstab.bak$(date '+%Y%m%d%H%M%S')
Redhat
sed -i "s//dev/mapper/rhel-swap/#/dev/mapper/rhel-swap/g" /etc/fstab
CentOS
sed -i "s//dev/mapper/centos-swap/#/dev/mapper/centos-swap/g" /etc/fstab
重新挂载全部挂载点
mount -a
（验证）查看swap
free -m
cat /proc/swaps
禁用Swap后，重启Kubelet组件：
systemctl daemon-reload
systemctl restart kubelet