参考：http://tieba.baidu.com/p/3233996339#57290767555l
在CentOS中配置静态IP后不生效。
解决办法：将/etc/sysconfig/network-scripts/ifcfg-eth0文件中的DEVICE=eth0注释掉
解决过程：
一开始，配置文件/etc/sysconfig/network-scripts/ifcfg-eth0内容如下：
1TYPE=Ethernet 2PROXY_METHOD=none 3BROWSER_ONLY=no 4BOOTPROTO=static 5DEFROUTE=yes 6NM_CONTROLLED="no" 7IPV4_FAILURE_FATAL=no 8IPV6INIT=yes 9IPV6_AUTOCONF=yes 10IPV6_DEFROUTE=yes 11IPV6_FAILURE_FATAL=no 12IPV6_ADDR_GEN_MODE=stable-privacy 13NAME=eth0 14DEVICE=eth0 15ONBOOT=yes 16IPADDR=192.168.30.140 17NETMASK=255.255.255.0 18GETWAY=192.168.1.1 19DNS1=114.114.114.114
试了网上其他人说的方法，比如
方法1. 禁用NetworkManager
systemctl stop NetworkManager
systemctl disable NetworkManager
方法2. 在/etc/sysconfig/network-scripts/ifcfg-eth0文件中设置
NM_CONTROLLED="no"
还试了其他一些方法，都没用。而且发现使用 systemctl restart network报错：
[root@node05 ~]# systemctl restart network
Job for network.service failed because the control process exited with error code. See "systemctl status network.service" and "journalctl -xe" for details.
[root@node05 ~]# systemctl status network
● 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 Fri 2019-04-26 09:03:05 EDT; 8s ago
Docs: man:systemd-sysv-generator(8)
Process: 9950 ExecStart=/etc/rc.d/init.d/network start (code=exited, status=1/FAILURE)
Apr 26 09:03:05 node05 network[9950]: RTNETLINK answers: File exists
Apr 26 09:03:05 node05 network[9950]: RTNETLINK answers: File exists
Apr 26 09:03:05 node05 network[9950]: RTNETLINK answers: File exists
Apr 26 09:03:05 node05 network[9950]: RTNETLINK answers: File exists
Apr 26 09:03:05 node05 network[9950]: RTNETLINK answers: File exists
Apr 26 09:03:05 node05 network[9950]: RTNETLINK answers: File exists
Apr 26 09:03:05 node05 systemd[1]: network.service: control process exited, code=exited status=1
Apr 26 09:03:05 node05 systemd[1]: Failed to start LSB: Bring up/down networking.
Apr 26 09:03:05 node05 systemd[1]: Unit network.service entered failed state.
Apr 26 09:03:05 node05 systemd[1]: network.service failed.
最终在贴吧里看到将DEVICE=eth0注释掉的方法，试了一下，静态IP生效了，但是systemctl restart network仍然报错。原因未知。。。。反正静态IP配置好了，但是浪费了好多时间。。。
2019/4/27 把DEVICE注释掉后不能联网了，why....
2019/5/17 将路由地址，默认网关，DNS配置好可解决大部分配置静态地址后不能上网的问题。
eg.
1[root@node04 test]# ifconfig 2ens33: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500 3 inet 192.168.30.139 netmask 255.255.255.0 broadcast 192.168.30.255 4 inet6 fe80::3711:f55c:b51d:9cc7 prefixlen 64 scopeid 0x20<link> 5 ether 00:0c:29:f3:da:5a txqueuelen 1000 (Ethernet) 6 RX packets 163813 bytes 21019361 (20.0 MiB) 7 RX errors 0 dropped 0 overruns 0 frame 0 8 TX packets 197627 bytes 24532180 (23.3 MiB) 9 TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0 10 11lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536 12 inet 127.0.0.1 netmask 255.0.0.0 13 inet6 ::1 prefixlen 128 scopeid 0x10<host> 14 loop txqueuelen 1000 (Local Loopback) 15 RX packets 63821 bytes 9132036 (8.7 MiB) 16 RX errors 0 dropped 0 overruns 0 frame 0 17 TX packets 63821 bytes 9132036 (8.7 MiB) 18 TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0 19 20[root@node04 test]# route 21Kernel IP routing table 22Destination Gateway Genmask Flags Metric Ref Use Iface 23default gateway 0.0.0.0 UG 100 0 0 ens33 24192.168.30.0 0.0.0.0 255.255.255.0 U 100 0 0 ens33 25 26[root@node04 network-scripts]# pwd 27/etc/sysconfig/network-scripts 28[root@node04 network-scripts]# cat ifcfg-eth0 29TYPE=Ethernet 30PROXY_METHOD=none 31BROWSER_ONLY=no 32BOOTPROTO=static 33DEFROUTE=yes 34IPV4_FAILURE_FATAL=no 35IPV6INIT=yes 36IPV6_AUTOCONF=yes 37IPV6_DEFROUTE=yes 38IPV6_FAILURE_FATAL=no 39IPV6_ADDR_GEN_MODE=stable-privacy 40NAME=eth0 41DEVICE=eth0 42ONBOOT=yes 43IPADDR=192.168.30.138 44NETMASK=255.255.255.0 45GETWAY=192.168.1.1 46DNS1=114.114.114.114