一大早跑个docker玩玩，很开心的从本地访问服务器上的nginx服务，感觉哪里不对劲，想想我的服务器开了防火墙，而nginx映射对口我并没有加入防火墙，居然能访问，起了疑心就去看个究竟，一看发现sy
一大早跑个docker玩玩，很开心的从本地访问服务器上的nginx服务，感觉哪里不对劲，想想我的服务器开了防火墙，而nginx映射对口我并没有加入防火墙，居然能访问，起了疑心就去看个究竟，一看发现systemctl status firewalld.service命令居然无效，报的错误是
Unit firewalld.service could not be found难道是防火墙被卸载了，由于最近刚刚安装了docker，怀疑是不是这个原因，于是yum install firewalld，
执行systemctl start irewalld.service，报了另一个错误：
Job for firewalld.service failed because the control process exited with error code. See "systemctl status firewalld.service" and "journalctl -xe" for details.根据提示执行systemctl status firewalld.service和journalctl -xe，看了半天没弄明白，
systemctl status firewalld.service执行结果 ：
firewalld.service - firewalld - dynamic firewall daemon Loaded: loaded (/usr/lib/systemd/system/firewalld.service; enabled; vendor preset: enabled) Active: failed (Result: exit-code) since Tue 2017-04-25 10:15:51 CST; 2min 4s ago Docs: man:firewalld(1) Process: 3698 ExecStart=/usr/sbin/firewalld --nofork --nopid $FIREWALLD_ARGS (code=exited, status=1/FAILURE) Main PID: 3698 (code=exited, status=1/FAILURE)Apr 25 10:15:51 test systemd[1]: Starting firewalld - dynamic firewall daemon...Apr 25 10:15:51 test systemd[1]: firewalld.service: main process exited, code=exited, status=1/FAILUREApr 25 10:15:51 test systemd[1]: Failed to start firewalld - dynamic firewall daemon.Apr 25 10:15:51 test systemd[1]: Unit firewalld.service entered failed state.Apr 25 10:15:51 test systemd[1]: firewalld.service failed.另一个执行结果也贴一段：
Apr 25 10:10:22 test systemd[1]: Unit firewalld.service entered failed state.Apr 25 10:10:22 test systemd[1]: firewalld.service failed.Apr 25 10:10:22 test polkitd[27822]: Unregistered Authentication Agent for unix-process:3582:1647230929 (system bus name :1.6509, object path /org/freedesktop/PolicyKit1/AuthenticationAgent, locale en_US.UTF-8) (disconnected from bus)Apr 25 10:13:57 test polkitd[27822]: Registered Authentication Agent for unix-process:3617:1647252460 (system bus name :1.6510 [/usr/bin/pkttyagent --notify-fd 5 --fallback], object path /org/freedesktop/PolicyKit1/AuthenticationAgent, locale en_US.UTApr 25 10:13:57 test polkitd[27822]: Unregistered Authentication Agent for unix-process:3617:1647252460 (system bus name :1.6510, object path /org/freedesktop/PolicyKit1/AuthenticationAgent, locale en_US.UTF-8) (disconnected from bus)Apr 25 10:15:12 test yum[3642]: Erased: firewalld-0.4.3.2-8.1.el7_3.2.noarchApr 25 10:15:12 test dbus[9212]: [system] Reloaded configurationApr 25 10:15:12 test systemd[1]: Reloading.Apr 25 10:15:12 test systemd[1]: Configuration file /usr/lib/systemd/system/ebtables.service is marked executable. Please remove executable permission bits. Proceeding anyway.Apr 25 10:15:24 test polkitd[27822]: Registered Authentication Agent for unix-process:3665:1647261079 (system bus name :1.6511 [/usr/bin/pkttyagent --notify-fd 5 --fallback], object path /org/freedesktop/PolicyKit1/AuthenticationAgent, locale en_US.UTApr 25 10:15:24 test polkitd[27822]: Unregistered Authentication Agent for unix-process:3665:1647261079 (system bus name :1.6511, object path /org/freedesktop/PolicyKit1/AuthenticationAgent, locale en_US.UTF-8) (disconnected from bus)Apr 25 10:15:42 test dbus[9212]: [system] Reloaded configurationApr 25 10:15:42 test dbus[9212]: [system] Reloaded configurationApr 25 10:15:42 test systemd[1]: Reloading.Apr 25 10:15:42 test systemd[1]: Configuration file /usr/lib/systemd/system/ebtables.service is marked executable. Please remove executable permission bits. Proceeding anyway.Apr 25 10:15:42 test yum[3673]: Installed: firewalld-0.4.3.2-8.1.el7_3.2.noarchApr 25 10:15:51 test polkitd[27822]: Registered Authentication Agent for unix-process:3692:1647263798 (system bus name :1.6512 [/usr/bin/pkttyagent --notify-fd 5 --fallback], object path /org/freedesktop/PolicyKit1/AuthenticationAgent, locale en_US.UTApr 25 10:15:51 test systemd[1]: Starting firewalld - dynamic firewall daemon...-- Subject: Unit firewalld.service has begun start-up-- Defined-By: systemd-- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel-- -- Unit firewalld.service has begun starting up.Apr 25 10:15:51 test systemd[1]: firewalld.service: main process exited, code=exited, status=1/FAILUREApr 25 10:15:51 test systemd[1]: Failed to start firewalld - dynamic firewall daemon.-- Subject: Unit firewalld.service has failed-- Defined-By: systemd-- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel-- -- Unit firewalld.service has failed.-- -- The result is failed.Apr 25 10:15:51 test systemd[1]: Unit firewalld.service entered failed state.Apr 25 10:15:51 test systemd[1]: firewalld.service failed.Apr 25 10:15:51 test polkitd[27822]: Unregistered Authentication Agent for unix-process:3692:1647263798 (system bus name :1.6512, object path /org/freedesktop/PolicyKit1/AuthenticationAgent, locale en_US.UTF-8) (disconnected from bus)反正还是不怎么明白，就去看看防火墙正常的服务器，看下：
● firewalld.service - firewalld - dynamic firewall daemon Loaded: loaded (/usr/lib/systemd/system/firewalld.service; disabled; vendor preset: enabled) Active: active (running) since Wed 2017-01-04 09:57:11 CST; 3 months 19 days ago Main PID: 9897 (firewalld) CGroup: /system.slice/firewalld.service └─9897 /usr/bin/python -Es /usr/sbin/firewalld --nofork --nopidJan 04 09:57:11 test1 systemd[1]: Starting firewalld - dynamic firewall daemon...Jan 04 09:57:11 test1 systemd[1]: Started firewalld - dynamic firewall daemon.发现了这个，/usr/bin/python，想起前几天改过python版本，目录重命名了，再看下/usr/sbin/firewalld，是python脚本，且路径执行/usr/bin/python，改了下/usr/bin/python2 新目录，执行防火墙启动命令下，成功了。
总结：python环境的更改会导致python脚本写的服务器程序无法执行，以后要慎重修改python环境
