Centos7修改默认网卡名（改为eth0）以及网卡启动报错RTNETLINK answers: File exists处理

安装好centos7版本的系统后，发现默认的网卡名字有点怪，为了便于管理，可以手动修改。下面对centos7版本下网卡重命名操作做一记录：
1）编辑网卡信息
[root@linux-node2~]# cd /etc/sysconfig/network-scripts/                             #进入网卡目录
[root@linux-node2network-scripts]# mv ifcfg-eno16777728 ifcfg-eth0          #将默认的网卡名eno16777728改为eth0
[root@linux-node2network-scripts]# cat ifcfg-eth0                        #编辑网卡信息
TYPE=Ethernet
BOOTPROTO=static
DEFROUTE=yes
PEERDNS=yes
PEERROUTES=yes
IPV4_FAILURE_FATAL=no
NAME=eth0                                    #name修改为eth0
ONBOOT=yes
IPADDR=192.168.56.12
NETMASK=255.255.255.0
GATEWAY=192.168.56.2
DNS1=192.168.56.2

2）修改grub
[root@linux-node2~]# cat /etc/sysconfig/grub                  #编辑内核信息,添加红色字段的
GRUB_TIMEOUT=5
GRUB_DEFAULT=saved
GRUB_DISABLE_SUBMENU=true
GRUB_TERMINAL_OUTPUT="console"
GRUB_CMDLINE_LINUX="crashkernel=autorhgb net.ifnames=0 biosdevname=0 quiet"
GRUB_DISABLE_RECOVERY="true"

[root@linux-node2~]# grub2-mkconfig -o /boot/grub2/grub.cfg       #生成启动菜单
Generatinggrub configuration file ...
Foundlinux image: /boot/vmlinuz-3.10.0-229.el7.x86_64
Foundinitrd image: /boot/initramfs-3.10.0-229.el7.x86_64.img
Foundlinux image: /boot/vmlinuz-0-rescue-1100f7e6c97d4afaad2e396403ba7f61
Foundinitrd image: /boot/initramfs-0-rescue-1100f7e6c97d4afaad2e396403ba7f61.img
Done

也可以在开机启动加载安装系统界面设置。

3）验证是否修改成功

[root@linux-node2~]# reboot                           #必须重启系统生效
[root@linux-node2~]# yum install net-tools                   #默认centos7不支持ifconfig 需要看装net-tools包
[root@linux-node2~]# ifconfig eth0                 #在次查看网卡信息
eth0:flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500

inet 192.168.56.12 netmask 255.255.255.0 broadcast 192.168.56.255

inet6 fe80::20c:29ff:fe5c:7bb1 prefixlen 64 scopeid 0x20<link>

ether 00:0c:29:5c:7b:b1 txqueuelen 1000 (Ethernet)

RX packets 152 bytes 14503 (14.1 KiB)

RX errors 0 dropped 0 overruns 0 frame 0

TX packets 98 bytes 14402 (14.0 KiB)

TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0 

centos7启动网卡服务报错“RTNETLINK answers: File exists”的解决方法

[root@localhost network-scripts]# service NetworkManager stop
Starting 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.

[root@localhost network-scripts]# 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 Mon 2017-03-20 18:41:03 CST; 3min 49s ago
     Docs: man:systemd-sysv-generator(8)
  Process: 18880 ExecStart=/etc/rc.d/init.d/network start (code=exited, status=1/FAILURE)

Mar 20 18:41:03 localhost.localdomain network[18880]: RTNETLINK answers: File exists
Mar 20 18:41:03 localhost.localdomain network[18880]: RTNETLINK answers: File exists
Mar 20 18:41:03 localhost.localdomain network[18880]: RTNETLINK answers: File exists
Mar 20 18:41:03 localhost.localdomain network[18880]: RTNETLINK answers: File exists
Mar 20 18:41:03 localhost.localdomain network[18880]: RTNETLINK answers: File exists
Mar 20 18:41:03 localhost.localdomain network[18880]: RTNETLINK answers: File exists
Mar 20 18:41:03 localhost.localdomain systemd[1]: network.service: control process exited, code=exited status=1
Mar 20 18:41:03 localhost.localdomain systemd[1]: Failed to start LSB: Bring up/down networking.
Mar 20 18:41:03 localhost.localdomain systemd[1]: Unit network.service entered failed state.
Mar 20 18:41:03 localhost.localdomain systemd[1]: network.service failed.

原因分析和解决：
在centos下出现该故障的原因是启动网络的两个服务/etc/init.d/network 和 /etc/init.d/NetworkManager有冲突。
从根本上说是NetworkMaganager（NM）的带来的冲突，停用NetworkManager即可解决。重启即可。
[root@localhost network-scripts]# service NetworkManager stop
Redirecting to /bin/systemctl stop  NetworkManager.service
[root@localhost network-scripts]# systemctl start network.service
[root@localhost network-scripts]#