1. 查看狀態 systemctl status network.service 內容如下
● network.service - LSB: Bring up/down networking
Loaded: loaded (/etc/rc.d/init.d/network; bad; vendor preset: disabled)
Active: failed (Result: exit-code) since 五 2017-07-14 19:01:47 CST; 1min 16s ago
Docs: man:systemd-sysv-generator(8)
Process: 4681 ExecStart=/etc/rc.d/init.d/network start (code=exited, status=1/FAILURE)
CGroup: /system.slice/network.service
└─1192 /sbin/dhclient -H mini1 -1 -q -lf /var/lib/dhclient/dhclient--ens33.lease -pf /v...
7月 14 19:01:47 mini1 network[4681]: RTNETLINK answers: File exists
7月 14 19:01:47 mini1 network[4681]: RTNETLINK answers: File exists
7月 14 19:01:47 mini1 network[4681]: RTNETLINK answers: File exists
7月 14 19:01:47 mini1 network[4681]: RTNETLINK answers: File exists
7月 14 19:01:47 mini1 network[4681]: RTNETLINK answers: File exists
7月 14 19:01:47 mini1 network[4681]: RTNETLINK answers: File exists
7月 14 19:01:47 mini1 systemd[1]: network.service: control process exited, code=exited status=1
7月 14 19:01:47 mini1 systemd[1]: Failed to start LSB: Bring up/down networking.
7月 14 19:01:47 mini1 systemd[1]: Unit network.service entered failed state.
2. 和 NetworkManager 服務有沖突。
解決辦法如下：
1）執行 systemctl stop NetworkManager // 關閉NetworkManager
2）執行 systemctl disable NetworkManager.service // 關閉開機啟動NetworkManager
3）執行 reboot // 重啟系統就可以了。