今天在centOS 7下更改完静态ip后发现network服务重启不了，翻遍了网络，尝试了各种方法，终于解决了。
现把各种解决方法归纳整理，希望能让后面的同学少走点歪路。。。
首先看问题：执行service network restart命令后出现下面的错误：
-
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. [失败]
根据提示输入systemctl status network.service命令后出现如下错误信息：
-
● 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. -
7月 14 19:01:47 mini1 systemd[1]: network.service failed.
network服务启动不了首先保证/etc/sysconfig/network-scripts目录下的ifcfg-xxx（每台机器不一定相同）没有错误（如果你改动过的话），这里的错误指的在更改过程中因为手误敲错字母之类的。
网上最常见的几种做法如下：
1.和 NetworkManager 服务有冲突，这个好解决，直接关闭 NetworkManger 服务就好了， service NetworkManager stop，并且禁止开机启动 chkconfig NetworkManager off 。之后重启就好了。
2和配置文件的MAC地址不匹配，这个也好解决，使用ip addr（或ifconfig）查看mac地址
-
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN qlen 1 -
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: ens33: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000 -
link/ether 00:0c:29:b8:e7:21 brd ff:ff:ff:ff:ff:ff -
inet 192.168.65.141/24 brd 192.168.65.255 scope global dynamic ens33 -
valid_lft 1193sec preferred_lft 1193sec -
inet6 fe80::cca2:d835:f93:e637/64 scope link -
valid_lft forever preferred_lft forever
00:0c:29:b8:e7:21这个就是MAC地址了，将/etc/sysconfig/network-scripts/ifcfg-xxx中的HWADDR（如果没有就添加上）改成这个MAC地址
3.设定开机启动一个名为NetworkManager-wait-online服务，命令为：
systemctl enable NetworkManager-wait-online.service