问题
在查看或启动firewalld服务时，提示"Warning: firewalld.service changed on disk. Run 'systemctl daemon-reload' to reload units."
解决方法
- 按照提示，执行
systemctl daemon-reload - 接着执行
systemctl unmask firewalld.service - 然后再
systemctl start firewalld，即可成功开启firewalld服务
在查看或启动firewalld服务时，提示"Warning: firewalld.service changed on disk. Run 'systemctl daemon-reload' to reload units."
systemctl daemon-reload
systemctl unmask firewalld.service
systemctl start firewalld，即可成功开启firewalld服务