啟動networkservice時出現的錯誤
Restarting network (via systemctl): Job for network.service failed. See systemctl status network.service and journalctl -xn for details.

按照要求檢視錯誤資訊
$ sudo systemctl status network.service

network.service - LSB: Bring up/down networking
Loaded: loaded (/etc/rc.d/init.d/network)
Active: failed (Result: exit-code) since Fri 2017-03-22 15:31:20 EDT; 43s ago
Process: 2641 ExecStart=/etc/rc.d/init.d/network start (code=exited, status=1/FAILURE)

localhost.localdomain network[2641]: RTNETLINK answers: File exists
Mar 22 15:31:20 localhost.localdomain network[2641]: RTNETLINK answers: File exists
Mar 22 15:31:20 localhost.localdomain network[2641]: RTNETLINK answers: File exists
Mar 22 15:31:20 localhost.localdomain network[2641]: RTNETLINK answers: File exists
Mar 22 15:31:20 localhost.localdomain network[2641]: RTNETLINK answers: File exists
Mar 22 15:31:20 localhost.localdomain network[2641]: RTNETLINK answers: File exists
Mar 22 15:31:20 localhost.localdomain network[2641]: RTNETLINK answers: File exists
Mar 22 15:31:20 localhost.localdomain systemd[1]: network.service: control process exited, code=exited status=1
Mar 22 15:31:20 localhost.localdomain systemd[1]: Failed to start LSB: Bring up/down networking.
Mar 22 15:31:20 localhost.localdomain systemd[1]: Unit network.service entered failed state.

如何解決呢 經過幾個小時的查詢資料終於解決了

首先解決 Failed to start LSB: Bring up/down networking.
這個錯誤一般是HWADDR錯誤
首先輸入 ip addr

進入 cd /etc/sysconfig/network-scripts 目錄
vim ifcfg-ens**

Linux一般作為伺服器，所以ip可以按照你的需求來設定
如果是虛擬機器 閘道器則要與主機閘道器一致
主機閘道器的檢視
進入cmd 命令視窗
輸入 ipconfig /all

ifcfg-ens**修改好了之後
啟動network 成功顯示

[root@localhost
 
 network-scripts]# service network restart
Restarting network (via systemctl):                        [  確定  ]

成功啟動network之後可能會遇到
主機ping不通虛擬機器 虛擬機器可以ping通主機的情況

網上大部分解決辦法都是說切換成橋接模式
其實切換成橋接模式也不一定可以解

主機ping不通虛擬機器 虛擬機器可以ping通主機這種情況最有可能是虛擬的ip和網路介面卡的ip不在一個網段上，當主機想要ping虛擬機器時，先得經過VM8 但是VM8得ip並不是和虛擬機器在同一網段上，所有就找不到虛擬機器，就會提示訪問超時。
所以解決辦法就是將VM8的ip設定成與虛擬機器ip地址在同一網段上

然後主機可以ping通虛擬機器了