1、执行 service network restart 出现以下错误
Restarting network (via systemctl): Job for network.service failed. See 'systemctl status network.service' and 'journalctl -xn' for details.
2、根据上面的提示，执行“systemctl status network.service”输出以下的类似信息：
[root@localhost ~]# 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 三 2014-11-05 15:30:10 CST; 1min 5s ago
11月 05 15:30:10 localhost.localdomain network[2920]: RTNETLINK answers: File exists
11月 05 15:30:10 localhost.localdomain network[2920]: RTNETLINK answers: File exists
11月 05 15:30:10 localhost.localdomain network[2920]: RTNETLINK answers: File exists
11月 05 15:30:10 localhost.localdomain network[2920]: RTNETLINK answers: File exists
11月 05 15:30:10 localhost.localdomain network[2920]: RTNETLINK answers: File exists
11月 05 15:30:10 localhost.localdomain network[2920]: RTNETLINK answers: File exists
11月 05 15:30:10 localhost.localdomain network[2920]: RTNETLINK answers: File exists
11月 05 15:30:10 localhost.localdomain systemd[1]: network.service: control process exited, code=exited status=1
11月 05 15:30:10 localhost.localdomain systemd[1]: Failed to start LSB: Bring up/down networking.
11月 05 15:30:10 localhost.localdomain systemd[1]: Unit network.service entered failed state.
3、针对上面的提示信息，如何进行修正，接下来进行了一系列的查找（此处省略2000字+无数的绝望+无数的泪），最后还是google给力(其他的搜索浪费时间)，找到解决的办法，其实很简单（由于centos7中没有70-persistent-net.rules这个文件，复制出来的虚拟机(vmware）需要修改mac地址），就是修改mac地址。
4、如何查看centos7复制出来的虚拟机的mac地址，需要执行 “ip addr”，输出如下的类似信息：
[root@localhost ~]# ip addr
1: lo:
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
valid_lft forever preferred_lft forever
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: eno16777736:
link/ether 00:0f:19:10:12:f1 brd ff:ff:ff:ff:ff:ff
inet 192.168.38.135/24 brd 192.168.38.255 scope global dynamic eno16777736
valid_lft 1681sec preferred_lft 1681sec
inet6 fe80::20c:11aa:ae11:4fe4/64 scope link
valid_lft forever preferred_lft forever
注意上面加粗加红的字，这就是新的mac地址。
接下来就剩下修改ifcfg-XXX文件了，只修改HWADDR就可以了。接下来执行service network restart 就正常了。