Enabling hotplug support for bonded network cards

This document (7008625) is provided subject to the disclaimer at the end of this document.

Environment

SUSE Linux Enterprise Server 11 Service Pack 1

Situation

When replacing a hotplug supported network card/device, which is part of a bonded network interface, the replaced card never gets enslaved into the bond.

The reasons for this are :

By default the YaST network module creates Udev rules and configuration files for network cards based on their MAC address. When the physical network card for e.g. eth2 gets replaced, the replaced card has a new MAC address. This then leads to creation of a new interface (e.g. eth3).
Since the configuration file of the bond points to the interface name of each slave, the system does not know about this name switch and thus the replaced card does not get enslaved by the ifup script.
The sysconfig scripts in SUSE Linux Enterprise Server (SLES) 11 Service Pack (SP) 1 do not contain code for the ifup script to detect which bond a network interface belongs to when performing a hotplug operation.

Resolution

In order to enable hotplug operations of bonded network cards, the following steps must be performed :

Ensure the (updated) sysconfig package version 0.71.30-0.11.1 (or newer) is installed on the system.
In the YaST Network Settings module (yast2 lan) switch from MAC-based to Bus ID based Udev rules for each bonded network card like this :

Edit the selected network card
By default YaST sets the card to use DHCP. Make sure it is set to "No IP Address (for bonding devices)".
Select Hardware and Change to edit the Udev rules
Change Rule by from MAC address to BusID
Save the changes and exit the YaST module.

It is not necessary to reboot the system for the changes to work - they will work as soon as the configuration is written.

Disclaimer

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