Bridging and LACP will be configured through puppet, but these intructions should serve as background and to help debug. A bridge is basically an in-kernel network switch, allowing multiple virtual interfaces to communicate with one another at layer 2. LACP, or interface bonding, is a protocol that allows the bandwidth of multiple interfaces to be aggregated together and treated as a single interface. The type of bonding we use, 802.3ad, specifies that the bandwidth of the bonded interface will be the sum of the bandwidth of each child interface, while providing fault-tolerance in case a particular sub interface goes down.
On Debian we can configure the network interfaces to come up at boot by adding
We use bond-mode 4, or 802.3ad. Other types are available, like active-fallback or load balancing, but we use 802.3ad. Link aggregation needs to be configured on the switch as well to work. Instructions for doing so can be found in the documentation for the switch.
Configuring the bonding interface is relatively simple. One must first install
identify the physical interfaces that will be slaved to the bond virtual interface. Then, write
the following to the config file:
iface bond0 inet manual
slaves <iface> <iface> ...
What do these options mean? The first line indicates the interfaces that are going to participate in the bond. The corresponding ports on the switch are the ones that are going to be aggregated into a channel-group/port-channel. The second line configures the type of aggregation, 802.3ad in our case, while the third configures the frequency in miliseconds that the interfaces are inspected for link failure and the fourth indicates the rate at which LACP PDUs are sent, 1 implying "fast", at a PDU sent every second instead of every 30 seconds ("slow").
If the bond interface is going to be the primary interface on the host, you may want to change
static and add addressing information by adding
fields to the stanza. If the bond interface is going to be part of a bridge, leave it as
Write the following stanzas to the config file. If using a bridge it's likely you want the bridge to expose the addressing information for the host.
iface br0 inet static
iface br0 inet6 static
Much configuration can be done by hand by using the
ip command. This is useful
for debugging and initial configuration but does not survive reboots.
$ ip link add bond0 type bond mode 4 miimon 100
$ ip link set <iface> master bond0
$ ip link show type bond_slave