剛剛裝好的虛擬機突然不能上網了，報錯很詭異，具體報錯如下：
/etc/init.d/network restart
Restarting network (via systemctl): Job for network.service failed because the control process exited with error code. See "systemctl status network.service" and "journalctl -xe" for details.
[失敗]
使用systemctl status network.service命令查看結果如下：
network.service - LSB: Bring up/down networking
Loaded: loaded (/etc/rc.d/init.d/network)
Active: failed (Result: exit-code) since 三 2016-08-17 11:34:36 CST; 54s ago
Docs: man:systemd-sysv-generator(8)
Process: 3847 ExecStart=/etc/rc.d/init.d/network start (code=exited, status=1/FAILURE)
8月 17 11:34:36 python.cn network[3847]: RTNETLINK answers: File exists
8月 17 11:34:36 python.cn network[3847]: RTNETLINK answers: File exists
8月 17 11:34:36 python.cn network[3847]: RTNETLINK answers: File exists
8月 17 11:34:36 python.cn network[3847]: RTNETLINK answers: File exists
8月 17 11:34:36 python.cn network[3847]: RTNETLINK answers: File exists
8月 17 11:34:36 python.cn network[3847]: RTNETLINK answers: File exists
8月 17 11:34:36 python.cn systemd[1]: network.service: control process exited, code=exited status=1
8月 17 11:34:36 python.cn systemd[1]: Failed to start LSB: Bring up/down networking.
8月 17 11:34:36 python.cn systemd[1]: Unit network.service entered failed state.
8月 17 11:34:36 python.cn systemd[1]: network.service failed.
查看系統日誌，報錯如下：
Aug 17 11:34:36 python network: RTNETLINK answers: File exists
Aug 17 11:34:36 python network: RTNETLINK answers: File exists
Aug 17 11:34:36 python network: RTNETLINK answers: File exists
Aug 17 11:34:36 python network: RTNETLINK answers: File exists
Aug 17 11:34:36 python network: RTNETLINK answers: File exists
Aug 17 11:34:36 python network: RTNETLINK answers: File exists
Aug 17 11:34:36 python network: RTNETLINK answers: File exists
Aug 17 11:34:36 python network: RTNETLINK answers: File exists
Aug 17 11:34:36 python network: RTNETLINK answers: File exists
Aug 17 11:34:36 python systemd: network.service: control process exited, code=exited status=1
Aug 17 11:34:36 python systemd: Failed to start LSB: Bring up/down networking.
Aug 17 11:34:36 python systemd: Unit network.service entered failed state.
Aug 17 11:34:36 python systemd: network.service failed.
Aug 17 11:36:28 python systemd: Starting LSB: Bring up/down networking...
Aug 17 11:36:29 python network: 正在打開環回接口： 無法載入文件 '/etc/sysconfig/network-scripts/ifcfg-lo'
Aug 17 11:36:29 python network: 無法載入文件 '/etc/sysconfig/network-scripts/ifcfg-lo'
Aug 17 11:36:29 python network: 無法載入文件 '/etc/sysconfig/network-scripts/ifcfg-lo'
Aug 17 11:36:29 python network: 無法載入文件 '/etc/sysconfig/network-scripts/ifcfg-lo'
Aug 17 11:36:29 python network: [ 確定 ]
Aug 17 11:36:29 python network: 正在打開接口 eno16777736： 錯誤：激活連接失敗：No suitable device found for this connection.
經查，確認/etc/sysconfig/network-scripts/ifcfg-lo文件是存在的。問題出現在哪裏呢？無法，只好百度一下吧，百度出來的結果竟然基本一樣。
百度答案：
mac地址不對，修改mac地址。
也許有人確實是mac問題，但是莫名其妙怎麼可能mac地址更改了，除非你添加新網卡或者克隆的虛擬機。
我特麼真笑了，天下百度文章一大抄啊。。。。。。。。
沒辦法了，Google一下吧，偶然看到一個文章，大意是跟系統自帶的NetworkManager這個管理套件有關係，關掉就可以解決。
試一下：
systemctl stop NetworkManager
systemctl disable NetworkManager
Removed symlink /etc/systemd/system/multi-user.target.wants/NetworkManager.service.
Removed symlink /etc/systemd/system/dbus-org.freedesktop.NetworkManager.service.
Removed symlink /etc/systemd/system/dbus-org.freedesktop.nm-dispatcher.service.
重新啓動網絡：
systemctl start network.service
ifconfig |grep eno
eno16777736: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 192.168.1.192 netmask 255.255.255.0 broadcast 192.168.1.255
inet6 fe80::20c:29ff:fe3d:b305 prefixlen 64 scopeid 0x20<link>
ether 00:0c:29:3d:b3:05 txqueuelen 1000 (Ethernet)
RX packets 2 bytes 120 (120.0 B)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 22 bytes 3551 (3.4 KiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
網絡正常啓動，訪問正常。