Unable to rename network devices named em(1,2,3) in yast.

This document (7011468) is provided subject to the disclaimer at the end of this document.

Environment

SUSE Linux Enterprise Server 11
Dell PowerEdge server

Situation

Unable to rename on board, or addon network cards. Changing device names or Network interface cards in Yast, or by modifying /etc/udev/rules.d/70-persistent-net.rules does not take effect. Networking is fine and functions properly with the em* naming convention, but the customer would prefers the eth* naming convention.

To verify this condition, open terminal, and run the following commands.

#ifconfig | grep HW
em1 Link encap:Etherenet HWaddr 00:11:43:0C:CE:7D

You will see similar output to this if you are experiencing this condition. em(x) is the default naming convention for on board devices managed by biosdevname utility. Many times if an add on card is present you will see pnp(x) instead

#ls /etc/udev/rules.d | grep biosdevname.rules

71-biosdevname.rules

If the file 71-biosdevname.rules exists the utility is in use, or has been at one time.

Resolution

1. Add the kernel boot parameter "biosdevname=0" in /boot/grub/menu.lst to the corresponding kernel you are booting from.

Open /boot/grub/menu.lst with an editor of your choice, and add the biosdevname=0 under the kernel you are booting to.

2. Create a copy of /etc/udev/rules.d/70-persistent-net.rules before clearing and letting it boot process recreate it.

Open terminal, and run the following.

#cp /etc/udev/rules.d/70-persistent-net.rules /etc/udev/rules.d/70-persistent-net.rules.old

#cat < /dev/null > /etc/udev/rules.d/70-persistent-net.rules

3. Rename each corresponding device script in /etc/sysconfig/network
****IMPORTANT*****
Because bootdevname will not be managing your devices any longer it is important that all devices be renamed to the conventional eth0, eth1, etc naming convention. Any devices not renamed here will need to be reconfigured.

# mv /etc/sysconfig/network/ifcfg-em1 /etc/sysconfig/network/ifcfg-eth0
(where ifcfg-em1 is the current device you wish to rename to eth0)

4. Reboot server (Upon rebooting the server your network devices can now be further modified in the traditional manner ie Yast.)

Cause

This issue is caused because network devices are being managed by the biosdevname utility. This utility has corresponding BIOS support, by renaming on board network interfaces to em[1234], which maps to Embedded NIC[1234] as labeled on server chassis. (em stands for ethernet-on-motherboard.)

Additional Information

It is possible that your server will require the bootdevutility to manage the network devices in which case this solution may not work for your environment.

Disclaimer

This Support Knowledgebase provides a valuable tool for SUSE customers and parties interested in our products and solutions to acquire information, ideas and learn from one another. Materials are provided for informational, personal or non-commercial use within your organization and are presented "AS IS" WITHOUT WARRANTY OF ANY KIND.