由於RHEL7中採用新的網卡名稱命名方法，導致網卡名變得難以理解和記憶，本文介紹怎樣將網卡名稱修改爲傳統的eth0的命名方式，可以實現定義任意網卡爲eth0.
網卡重命名過程介紹
要修改網卡名稱，首先我們要了解linux網卡設備重命名的過程，根據紅帽官方文檔介紹，設備重命名的過程如下：
A rule in /usr/lib/udev/rules.d/60-net.rules instructs the udev helper utility,/lib/udev/rename_device,to look into all /etc/sysconfig/networkscripts/ifcfg-suffix files.If it finds an ifcfg file with a HWADDR entry matching the MAC address of an interface it renames the interface to the name given in the ifcfg file by the DEVICE directive.
A rule in /usr/lib/udev/rules.d/71-biosdevname. rules instructs biosdevname to rename the interface according to its naming policy, provided that it was not renamed in a previous step, biosdevname is installed, and biosdevname=0 was not given as a kernel command on the boot command line.
A rule in /lib/udev/rules.d/75-net-description.rules instructs udev to fill in the internal udev device property values ID_NET_NAME_ONBOARD, ID_NET_NAME_SLOT, ID_NET_NAME_PATH, ID_NET_NAME_MAC by examining the network interface device.Note,that some device properties might be undefined.
A rule in /usr/lib/udev/rules.d/80-net-name-slot.rules instructs udev to rename the interface, provided that it was not renamed in step 1 or 2, and the kernel parameter net.ifnames=0 was not given, according to the following priority: ID_NET_NAME_ONBOARD,ID_NET_NAME_SLOT,ID _NET_NAME_PATH. It falls through to the next in the list, if one is unset. If none of these are set, then the interface will not be renamed.
簡單翻譯如下：
/usr/lib/udev/rules.d/60-net.rules文件中的規則會讓udev幫助工具/lib/udev/renamedevice查看所有/etc/sysconfig/networkscripts/ifcfg-suffix文件。如果發現包含HWADDR條目的ifcfg文件與某個接口的MAC地址匹配，它會將該接口重命名爲ifcfg文件中由DEVICE指令給出的名稱。
/usr/lib/udev/rules.d/71-biosdevname.rules中的規則讓biosdevname根據其命名策略重命名該接口，該命名方法執行的前提是在上一步中沒有重命名該接口，但是已安裝biosdevname、且在boot命令行中將biosdevname=0作爲內核命令給出。
/lib/udev/rules.d/75-net-description.rules中的規則讓udev通過檢查網絡接口設備，填寫內部udev設備屬性值ID_NET_NAME_ONBOARD、ID_NET_NAME_SLOT、ID_NET_NAME_PATH。注：有些設備屬性可能處於未定義狀態。
/usr/lib/udev/rules.d/80-net-name-slot.rules中的規則讓udev重命名該接口，優先順序如下：ID_NET_NAME_ONBOARD、ID_NET_NAME_SLOT、ID_NET_NAME_PATH。也就是說，沒有在步驟1或2中重命名該接口，同時未給出內核參數net.ifnames=0，則會按照該規則進行重命名。按照該規則重命名時，若一個參數未設定，則會按列表的順序設定下一個。如果沒有設定任何參數，則不會重命名該接口。
網卡重命名方法
根據以上介紹，這裏可以按照步驟1中的介紹來進行網卡重命名：
ifconfig 命令查看各網卡MAC地址
[root@test01 ~]# ifconfig enp0s3: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500 ether 08:00:27:43:c1:1d txqueuelen 1000 (Ethernet) RX packets 233 bytes 43354 (42.3 KiB) RX errors 0 dropped 0 overruns 0 frame 0 TX packets 0 bytes 0 (0.0 B) TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0 enp0s8: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500 inet 192.168.56.102 netmask 255.255.255.0 broadcast 192.168.56.255 inet6 fe80::a00:27ff:fe56:9530 prefixlen 64 scopeid 0x20<link> ether 08:00:27:56:95:30 txqueuelen 1000 (Ethernet) RX packets 259 bytes 48117 (46.9 KiB) RX errors 0 dropped 0 overruns 0 frame 0 TX packets 50 bytes 8735 (8.5 KiB) TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0 enp0s9: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500 inet 192.168.56.101 netmask 255.255.255.0 broadcast 192.168.56.255 inet6 fe80::a00:27ff:fea5:4fd prefixlen 64 scopeid 0x20<link> ether 08:00:27:a5:04:fd txqueuelen 1000 (Ethernet) RX packets 1213 bytes 131145 (128.0 KiB) RX errors 0 dropped 0 overruns 0 frame 0 TX packets 771 bytes 86683 (84.6 KiB) TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0 lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536 inet 127.0.0.1 netmask 255.0.0.0 inet6 ::1 prefixlen 128 scopeid 0x10<host> loop txqueuelen 0 (Local Loopback) RX packets 1220 bytes 105112 (102.6 KiB) RX errors 0 dropped 0 overruns 0 frame 0 TX packets 1220 bytes 105112 (102.6 KiB) TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
由此可知，網卡MAC地址分別爲：
enp0s3: 08:00:27:43:c1:1d enp0s8: 08:00:27:56:95:30 enp0s9: 08:00:27:a5:04:fd
這裏將要修改網卡名稱的對應關係如下：
enp0s3: 08:00:27:43:c1:1d --eth0 enp0s8: 08:00:27:56:95:30 --eth1 enp0s9: 08:00:27:a5:04:fd --eth2 # 備註：可以自定義各網卡名稱的對應關係，如將enp0s8修改爲eth2，enp0s9修改爲eth2.
重命名網卡配置文件
[root@test01 ~]# cd /etc/sysconfig/network-scripts/ [root@test01 network-scripts]# ls ifcfg-* ifcfg-enp0s3 ifcfg-lo [root@test01 network-scripts]# # 如果沒有網卡配置文件，可以使用以下命令添加 [root@test01 network-scripts]# nmcli connection add type ethernet ifname enp0s8 con-name enp0s8 autoconnect yes 成功添加的連接 'enp0s8'（71306055-0869-4125-955a-4b7959cc9226）。 [root@test01 network-scripts]# nmcli connection add type ethernet ifname enp0s9 con-name enp0s9 autoconnect yes 成功添加的連接 'enp0s9'（9d5a3033-b478-4076-95b0-83e62aa62cbe）。 [root@test01 network-scripts]# ls ifcfg-* ifcfg-enp0s3 ifcfg-enp0s8 ifcfg-enp0s9 ifcfg-lo [root@test01 network-scripts]# mv ifcfg-enp0s3 ifcfg-eth0 [root@test01 network-scripts]# mv ifcfg-enp0s8 ifcfg-eth1 [root@test01 network-scripts]# mv ifcfg-enp0s9 ifcfg-eth2 [root@test01 network-scripts]# [root@test01 network-scripts]# ls ifcfg-* ifcfg-eth0 ifcfg-eth1 ifcfg-eth2 ifcfg-lo
修改網卡配置文件
修改好配置文件名稱後，修改或向配置文件中添加HWADDR，DEVICE,NAME參數。
[root@test01 network-scripts]# cat ifcfg-eth0 TYPE=Ethernet BOOTPROTO=none DEFROUTE=yes IPV4_FAILURE_FATAL=no IPV6INIT=no IPV6_AUTOCONF=yes IPV6_DEFROUTE=yes IPV6_PEERDNS=yes IPV6_PEERROUTES=yes IPV6_FAILURE_FATAL=no NAME=eth0 --這裏修改NAME=eth0 UUID=77c7f1b8-ddef-4d96-bf74-68ecedc99a1a DEVICE=eth0 --這裏修改DEVICE=eth0 ONBOOT=yes IPADDR=192.168.56.10 PREFIX=24 HWADDR=08:00:27:43:c1:1d --這裏添加HWADDR
按照以上方法修改所有網卡配置文件。
拷貝配置文件60-net.rules
[root@test01 network-scripts]# cp /usr/lib/udev/rules.d/60-net.rules /etc/udev/rules.d/
重啓系統查看網卡名稱
shutdown -r 0
按照以上方法修改，可以自由定義不同MAC地址的網卡對應的網卡名稱，在配置文件中添加完HWADDR的前提下，只需要修改配置文件名稱ifcfg-ethx和其中的DEVICE=ethx,NAME=ethx.
[root@test01 ~]# ifconfig eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500 ether 08:00:27:43:c1:1d txqueuelen 1000 (Ethernet) RX packets 9 bytes 3788 (3.6 KiB) RX errors 0 dropped 0 overruns 0 frame 0 TX packets 0 bytes 0 (0.0 B) TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0 eth1: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500 inet 192.168.56.102 netmask 255.255.255.0 broadcast 192.168.56.255 inet6 fe80::a00:27ff:fe56:9530 prefixlen 64 scopeid 0x20<link> ether 08:00:27:56:95:30 txqueuelen 1000 (Ethernet) RX packets 16 bytes 5825 (5.6 KiB) RX errors 0 dropped 0 overruns 0 frame 0 TX packets 21 bytes 4149 (4.0 KiB) TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0 eth2: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500 inet 192.168.56.101 netmask 255.255.255.0 broadcast 192.168.56.255 inet6 fe80::a00:27ff:fea5:4fd prefixlen 64 scopeid 0x20<link> ether 08:00:27:a5:04:fd txqueuelen 1000 (Ethernet) RX packets 66 bytes 11712 (11.4 KiB) RX errors 0 dropped 0 overruns 0 frame 0 TX packets 63 bytes 10460 (10.2 KiB) TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0