11.6. Bonding
11.6.1. Bonding Logic in Red Hat Enterprise Virtualization
The Red Hat Enterprise Virtualization Manager Administration Portal allows you to create bond devices using a graphical interface. There are several distinct bond creation scenarios, each with its own logic.
Two factors that affect bonding logic are:
- Are either of the devices already carrying logical networks?
- Are the devices carrying compatible logical networks? A single device cannot carry both VLAN tagged and non-VLAN tagged logical networks.
Table 11.3. Bonding Scenarios and Their Results
| Bonding Scenario | Result |
|---|---|
|
NIC + NIC
|
The Create New Bond window is displayed, and you can configure a new bond device.
If the network interfaces carry incompatible logical networks, the bonding operation fails until you detach incompatible logical networks from the devices forming your new bond.
|
|
NIC + Bond
|
The NIC is added to the bond device. Logical networks carried by the NIC and the bond are all added to the resultant bond device if they are compatible.
If the bond devices carry incompatible logical networks, the bonding operation fails until you detach incompatible logical networks from the devices forming your new bond.
|
|
Bond + Bond
|
If the bond devices are not attached to logical networks, or are attached to compatible logical networks, a new bond device is created. It contains all of the network interfaces, and carries all logical networks, of the component bond devices. The Create New Bond window is displayed, allowing you to configure your new bond.
If the bond devices carry incompatible logical networks, the bonding operation fails until you detach incompatible logical networks from the devices forming your new bond.
|
11.6.2. Bonding Modes
Red Hat Enterprise Virtualization supports the following common bonding modes:
- Mode 1 (active-backup policy) sets all interfaces to the backup state while one remains active. Upon failure on the active interface, a backup interface replaces it as the only active interface in the bond. The MAC address of the bond in mode 1 is visible on only one port (the network adapter), to prevent confusion for the switch. Mode 1 provides fault tolerance and is supported in Red Hat Enterprise Virtualization.
- Mode 2 (XOR policy) selects an interface to transmit packages to based on the result of an XOR operation on the source and destination MAC addresses modulo NIC slave count. This calculation ensures that the same interface is selected for each destination MAC address used. Mode 2 provides fault tolerance and load balancing and is supported in Red Hat Enterprise Virtualization.
- Mode 4 (IEEE 802.3ad policy) creates aggregation groups for which included interfaces share the speed and duplex settings. Mode 4 uses all interfaces in the active aggregation group in accordance with the IEEE 802.3ad specification and is supported in Red Hat Enterprise Virtualization.
- Mode 5 (adaptive transmit load balancing policy) ensures the outgoing traffic distribution is according to the load on each interface and that the current interface receives all incoming traffic. If the interface assigned to receive traffic fails, another interface is assigned the receiving role instead. Mode 5 is supported in Red Hat Enterprise Virtualization.
11.6.3. Creating a Bond Device Using the Administration Portal
Summary
You can bond compatible network devices together. This type of configuration can increase available bandwidth and reliability. You can bond multiple network interfaces, pre-existing bond devices, and combinations of the two.
A bond cannot carry both VLAN tagged and non-VLAN traffic.
Procedure 11.9. Creating a Bond Device using the Administration Portal
- Use the Hosts resource tab, tree mode, or the search function to find and select the host in the results list.
- Click the Network Interfaces tab in the details pane to list the physical network interfaces attached to the host.
- Click to open the Setup Host Networks window.
- Select and drag one of the devices over the top of another device and drop it to open the Create New Bond window. Alternatively, right-click the device and select another device from the drop-down menu.If the devices are incompatible, for example one is VLAN tagged and the other is not, the bond operation fails with a suggestion on how to correct the compatibility issue.
- Select the Bond Name and Bonding Mode from the drop-down menus.Bonding modes 1, 2, 4, and 5 can be selected. Any other mode can be configured using the Custom option.
- Click to create the bond and close the Create New Bond window.
- Assign a logical network to the newly created bond device.
- Optionally choose to Verify connectivity between Host and Engine and Save network configuration.
- Click accept the changes and close the Setup Host Networks window.
Result
Your network devices are linked into a bond device and can be edited as a single interface. The bond device is listed in the Network Interfaces tab of the details pane for the selected host.
Bonding must be enabled for the ports of the switch used by the host. The process by which bonding is enabled is slightly different for each switch; consult the manual provided by your switch vendor for detailed information on how to enable bonding.
11.6.4. Example Uses of Custom Bonding Options with Host Interfaces
You can create customized bond devices by selecting Custom from the Bonding Mode of the Create New Bond window. The following examples should be adapted for your needs. For a comprehensive list of bonding options and their descriptions, see the Linux Ethernet Bonding Driver HOWTO on Kernel.org.
Example 11.1. xmit_hash_policy
This option defines the transmit load balancing policy for bonding modes 2 and 4. For example, if the majority of your traffic is between many different IP addresses, you may want to set a policy to balance by IP address. You can set this load-balancing policy by selecting a Custom bonding mode, and entering the following into the text field:
mode=4 xmit_hash_policy=layer2+3
Example 11.2. ARP Monitoring
ARP monitor is useful for systems which can't or don't report link-state properly via ethtool. Set an
arp_interval on the bond device of the host by selecting a Custom bonding mode, and entering the following into the text field:
mode=1 arp_interval=1 arp_ip_target=192.168.0.2
Example 11.3. Primary
You may want to designate a NIC with higher throughput as the primary interface in a bond device. Designate which NIC is primary by selecting a Custom bonding mode, and entering the following into the text field:
mode=1 primary=eth0