Some deployment requires persistent ethernet adapter name and also requires some rules to keep the consistent NIC name across servers. This could be achieved by ‘udev‘. Let’s take an example to understand the udev rules required for such persistent naming scheme.
The requirement to change the network adapter names as per the deployment need:
1) The network adapter eth7 needs to be made as eth9.
2) The network adapter eth9 needs to be made as eth7.
Configuring persistent NIC names
Following are the steps :-
1. Backup the existing configuration files/folders as follows :
/etc/udev/rules.d/* /etc/sysconfig/network-scripts/*
2. Edit the udev rules under “/etc/udev/rules.d/” with the following changes in the udev rules file i.e “/etc/udev/rules.d/70-persistent-net.rules” :
Modify the Existing Parameters “eth7” to “eth9” & “eth9” to “eth7
# vi /etc/udev/rules.d/70-persistent-net.rules
# PCI device 0x8086:0x10f7 (ixgbe)
SUBSYSTEM=="net", ACTION=="add", DRIVERS=="?*", ATTR{address}=="00:1b:21:da:73:d9", ATTR{type}=="1", KERNEL=="eth*", NAME="eth7"
# PCI device 0x8086:0x105e (e1000e)
SUBSYSTEM=="net", ACTION=="add", DRIVERS=="?*", ATTR{address}=="00:00:c9:df:c4:47", ATTR{type}=="1", KERNEL=="eth*", NAME="eth9"
3. After the changes to udev rule is completed, modify the Network Configuration to match the new changes .i.e. eth7 device should be named as eth9 and vice-versa. Changes are required in the files “/etc/sysconfig/network-scripts/ifcfg-eth7” and in “/etc/sysconfig/network-scripts/ifcfg-eth9”.
# cat /etc/sysconfig/network-scripts/ifcfg-eth7 DEVICE=eth7 NM_CONTROLLED=yes ONBOOT=no TYPE=Ethernet BOOTPROTO=dhcp DEFROUTE=yes IPV4_FAILURE_FATAL=yes IPV6INIT=no NAME="System eth7" (Modify the Existing Parameter "eth7" to "mgmt-eth9") UUID=1e690eec-2d2c-007e-535f-a873a2b375d5 PREFIX=26 DNS1=10.253.2.254 HWADDR=00:1b:21:da:73:d9 USERCTL=no
# cat /etc/sysconfig/network-scripts/ifcfg-eth9: DEVICE=eth9 (Modify the Existing Parameter "eth9" to "eth7") NM_CONTROLLED=yes ONBOOT=yes TYPE=Ethernet BOOTPROTO=none DEFROUTE=yes IPV4_FAILURE_FATAL=yes IPV6INIT=no NAME=mgmt-eth9 (Modify the Existing Parameter "mgmt-eth9" to "eth7") UUID=d70dd704-4891-3f2d-b12e-79ffbc7bb9b8 IPADDR=10.253.248.144 PREFIX=26 GATEWAY=10.253.248.129 DNS1=10.253.2.254 HWADDR=00:00:c9:df:c4:47 NETMASK=255.255.255.192 USERCTL=no
4. Reboot the server after implementing the changes as suggested above. If the server reboot is not possible then the udev rules need to be reloaded and the network needs to be restarted to take the changes effectively.
# shutdown -r now