Topics: Networking, Red Hat / Linux

Linux bond interfaces

Linux allows binding multiple network interfaces into a single channel/NIC using special kernel module called bonding. According to official bonding documentation, The Linux bonding driver provides a method for aggregating multiple network interfaces into a single logical "bonded" interface. The behavior of the bonded interfaces depends upon the mode; generally speaking, modes provide either hot standby or load balancing services. Additionally, link integrity monitoring may be performed.

Setting up bounding is easy with RHEL v4.0. Red Hat Linux stores network configuration in /etc/sysconfig/network-scripts/ directory. First, you need to create bond0 config file:

# vi /etc/sysconfig/network-scripts/ifcfg-bond0
Append following lines to it:
Replace above IP address with your actual IP address. Save file and exit to shell prompt. Now open the configuration files for eth0 and eth1 in the same directory using the vi text editor and make sure file read as follows for eth0 interface:
# cat /etc/sysconfig/network-scripts/ifcfg-eth0
Repeat the same for the ifcfg-eth1 file, of course, set the DEVICE to eth1. Then, make sure that the following two lines are added to either /etc/modprobe.conf or /etc/modules.conf (see this page or also this page for more information):
alias bond0 bonding
options bond0 mode=1 miimon=100
Then load the bonding module:
# modprobe bonding
Restart networking service in order to bring up bond0 interface:
# service network restart
Verify everything is working:
# less /proc/net/bonding/bond0
Bonding Mode: load balancing (round-robin)
MII Status: up
MII Polling Interval (ms): 0
Up Delay (ms): 0
Down Delay (ms): 0

Slave Interface: eth0
MII Status: up
Link Failure Count: 0
Permanent HW addr: 00:0c:29:c6:be:59

Slave Interface: eth1
MII Status: up
Link Failure Count: 0
Permanent HW addr: 00:0c:29:c6:be:63

If you found this useful, here's more on the same topic(s) in our blog:

UNIX Health Check delivers software to scan Linux and AIX systems for potential issues. Run our software on your system, and receive a report in just a few minutes. UNIX Health Check is an automated check list. It will report on perfomance, capacity, stability and security issues. It will alert on configurations that can be improved per best practices, or items that should be improved per audit guidelines. A report will be generated in the format you wish, and the report includes the issues discovered and information on how to solve the issues as well.

Interested in learning more?