systemctl命令是系统服务管理器指令，它实际上将 service 和 chkconfig 这两个命令组合到一起。
任务旧指令新指令使某服务自动启动chkconfig --level 3 httpd onsystemctl enable httpd.service使某服务不自动启动chkconfig --level 3 httpd offsystemctl disable httpd.service检查服务状态service httpd statussystemctl status httpd.service（服务详细信息） systemctl is-active httpd.service （仅显示是否 Active)显示所有已启动的服务chkconfig --listsystemctl list-units --type=service启动某服务service httpd startsystemctl start httpd.service停止某服务service httpd stopsystemctl stop httpd.service重启某服务service httpd restartsystemctl restart httpd.service
例子：以nginx为例。 1.启动服务 systemctl start nginx.service
2.设为开机启动 systemctl enable nginx.service 3.停止开机启动 systemctl disable nginx.service
4.查看服务当前状态 systemctl status nginx.service
5.重启服务 systemctl restart nginx.service
6.停止服务 systemctl stop nginx.service 7.查看说有已启动服务 systemctl list -units --type=service
8.开启防火墙22端口 iptables -I INPUT -p tcp --dport 22 -j accept如果还有问题滚逼SELinux 修改/etc/selinux/config SELINUX=”disabled”
9.彻底关闭防火墙 sudo firewall-cmd --state //查看服务状态 sudo systemctl stop firewalld.service //停止防火墙 sudo systemctl disable firewalld.service //停止开机启动
