This is a brief article detailing the steps to configure network interface bonding on Debian Wheezy (7.0 stable). The procedure is very different from RHEL/CentOS. I will be configuring active-backup (i.e. failover) mode bonding - there are other modes available, including round-robin load-balanced, LACP aggregation, etc. Read /usr/share/doc/ifenslave-2.6/README.Debian or http://www.kernel.org/doc/Documentation/networking/bonding.txt for further information.

First, verify via ifconfig that your two slave interfaces are available - I’ll be bonding eth0 and eth1 into a bond called bond0:

Install the ifenslave package:

Next, stop networking. As you’re stopping networking, ensure that you’re connected to your host via a console of some form:

Modify /etc/network/interfaces. Remove (or comment out) any existing configuration for your slave interfaces (eth0 and eth1), and configure your new bond0 interface appropriately:

bond_miimon is the MII link monitoring frequency in milliseconds, and bond_{down,up}delay are the time, in milliseconds, to wait before disabling or enabling an interface in the bond (to safeguard against flapping), and should be a multiple of the bond_miimon value. You can adjust these values to suit your needs. These bond_<parameter> directives correlate to the <parameter> directives passed to the bonding module itself.

Once configured, start networking:

There is no need to fiddle with module loading (editing /etc/modules, creating a file under /etc/modprobe.d, etc.) - the ifenslave-2.6 package deposits scripts to do this for us. Take a look at /etc/network/if-pre-up.d/ifenslave to see this being done.

You can see the other scripts installed by ifenslave-2.6 with a dpkg -L:

Running ifconfig -a should now show the correct network configuration:

You can also view the contents of /proc/net/bonding/bond0 to check the status of the bond: