参考链接：https://www.cnblogs.com/gaohongyu/p/14479497.html
执行 yum -y install keepalived 时报：The GPG keys listed for the "MySQL 8.0 Community Server" repository are already installed but they are not correct for this package.
导致 无法安装 keepalived
解决：
如果已安装 mysql8，就跳过 检查数字签名，执行 ：yum -y install keepalived --nogpgcheck 进行安装
查看已安装服务列表：systemctl list-unit-files --type=service
启动：systemctl start keepalived
验证： ip addr
