CentOS7 防火墙启动失败 Failed to start firewalld - dynamic firewall daemon.

新买的阿里云服务器，防火墙启动失败，系统是 CentOS7，启动防火墙的时候启动失败

用命令 systemctl status firewalld 查看状态时显示下面信息

● firewalld.service - firewalld - dynamic firewall daemon

Loaded: loaded (/usr/lib/systemd/system/firewalld.service; disabled; vendor preset: enabled)

   Active: failed (Result: timeout) since 六 2020-06-20 11:28:47 CST; 11s ago

   Docs: man:firewalld(1)

   Process: 15632 ExecStart=/usr/sbin/firewalld --nofork --nopid $FIREWALLD_ARGS (code=exited, status=0/SUCCESS)

   Main PID: 15632 (code=exited, status=0/SUCCESS)

6月 20 11:27:16 izwz98ohfh4pkwbu0bn16gz systemd[1]: Starting firewalld - dynamic firewall daemon...

6月 20 11:27:17 izwz98ohfh4pkwbu0bn16gz firewalld[15632]: WARNING: AllowZoneDrifting is enabled. This is considered an insecure configuration option. It will b...g it now.

6月 20 11:28:46 izwz98ohfh4pkwbu0bn16gz systemd[1]: firewalld.service start operation timed out. Terminating.

6月 20 11:28:47 izwz98ohfh4pkwbu0bn16gz systemd[1]: Failed to start firewalld - dynamic firewall daemon.**

6月 20 11:28:47 izwz98ohfh4pkwbu0bn16gz systemd[1]: Unit firewalld.service entered failed state.**

6月 20 11:28:47 izwz98ohfh4pkwbu0bn16gz systemd[1]: firewalld.service failed.**

Hint: Some lines were ellipsized, use -l to show in full.

在网上找了很多原因，大多数都是说 Python 版本的问题，但是我的服务器是新开的，还是默认的 Python2 版本，后面证实确实不是版本问题

如果安装了 Python3，可能是版本问题，可以参考这里 链接

如果不是，则试试下面的方法

systemctl stop firewalld
pkill -f firewalld
systemctl start firewalld

方法参考来源