First of all let me start this off by saying that there is a lot of information out there on how to setup a dedicated storage interface on XenServer. However, I was unable to find anything specifically related to bonding two unmanaged interfaces and use them for as a dedicated uplink, which is seems rather silly to me as why would you not want to have a highly redundant network connection to your NFS storage. I digress.

Anyway, the first thing you need to do is to ssh into one of your XenServer hosts. In my environment I am building out a three node cluster and I need to make sure that I am working specifically with the first host in the cluster. So….

First thing you need to do is change the network backend of your Xenserver from "openvswitch" to "Linux Bridge". You accompish this with the following command.

#xe-switch-network-backend bridge.

Now you will need to reboot. Note that you can check your network-backend mode at any time with the following command.

#cat /etc/xensource/network.conf

First get the uuid of the local xenserver host, use the hostname to do this.

  # xe host-list name-label=xen01

The command above will return the uuid of the server.

uuid ( RO): 4a9971f7-1e59-4e02-b849-04d206ee7b2b
name-label ( RW): xen01
name-description ( RW): Default install of XenServer

Then you need to get a list of pifs on the host that you are working with (making sure to exclude any other host's interfaces). The command below will output this list. We will need to grab the uuids of eth2 and eth3, since they are the interfaces that we are going to use to build our bond. Note that we are running this command so that it will spit out our MAC addresses as well… make sure that you take note of these as you will need them.

 #xe pif-list host-uuid=4a9971f7-1e59-4e02-b849-04d206ee7b2bparams=uuid,device,MAC,host-uuid

Next we will tell XenServer to "forget" or un-manage eth2. Then we will do the same to eth3. We will use the uuids of these interfaces to identify them to XenServer.

Example with interface eth2 in unmanaged mode. Rinse and repeat for eth3.

# xe pif-forget uuid=97afe085-c679-3aa0-d09b-3c530ee3ac60

Then list all PIFs to ensure the unmanaged one is no longer in the list:

# xe pif-list host-uuid=97afe085-c679-3aa0-d09b-3c530ee3ac60

If you have successfully removed them its time to start creating your bond.

First define your bond in /etc/modprobe.conf. I am calling my bond, bond51

alias bonding bond51
options bond51 miimon=100 mode=7

Then edit /etc/sysconfig/network-scripts/ifcfg-eth2 and /etc/sysconfig/network-scripts/ifcfg-eth3. Make them look like the file below. Change the device name for ifcfg-eth3 to eth3.

DEVICE=eth2
BOOTPROTO=none
HWADDR=<MAC ADDRESS OF YOUR INTERFACE>
ONBOOT=yes
MASTER=bond51
SLAVE=yes

Then create /etc/sysconfig/network-scripts/ifcfg-bond0

DEVICE=bond51
IPADDR=<YOUR IP>
NETMASK=<YOUR NETMASK>
ONBOOT=yes
BOOTPROTO=static

Beep Boop. Ifup bond51 to bring up the bond and its slave members.

You can check the status of the bond via the command below.

cat /proc/net/bonding/bond51

Please know that I have done little more than reboot the XenServer host to make sure that the configuration that I built would persist across reboots, and failover from one interface to another. I have not tested performance yet in any way shape or form.