CentOS 7: Firewalld.service Oper

CentOS 7: Firewalld.service Operation Time Out – Systemctl Firewalld Issues

• question
  As the title, systemctl status firewalld show the service failed time out,
  but firewall-cmd --state show running. Ghost know the reason.
• solution
  systemctl stop firewalld ; pkill -f firewalld
  reference