XenCenter

Configuring NICs

Citrix Hypervisor automatically manages NICs as needed based on the related network, virtual network interface, server network, and bond configuration. You can view the available NICs, configure NIC bonds, and dedicate NICs to a specific function from the NICs tab.

NIC bonding can improve server resiliency by using two or more physical NICs as if they were one. Two or more NICs can be bonded to create a single, high-performing channel that provides connectivity between VMs and your external network. Three bond modes are supported:

Active-active: This mode provides load balancing of virtual machine traffic across the physical NICs in the bond. If one NIC within the bond fails, the server’s network traffic automatically routes over the second NIC.

Active-passive: This mode provides failover capability. Only one NIC in the bond is active. The inactive NIC becomes active if and only if the active NIC fails.

Link Aggregation Control Protocol (LACP) Bonding: This mode provides active-active bonding, where traffic is balanced between the bonded NICs. Unlike the active-active bond in a Linux bridge environment, LACP can load balance all traffic types.

Note:

Configure vSwitch as the network stack to be able to view the LACP bonding options in XenCenter and to create a LACP bond. Also, your switches must support the IEEE 802.3ad standard. The switch must contain a separate LAG group configured for each LACP bond on the host. For more details about creating LAG groups, see Networking.

When you bond separate NICs using XenCenter, a new NIC is created. This NIC is the bond master, and the other NICs are referred to as the bonded NICs. The NIC bond can then be connected to Citrix Hypervisor network to allow virtual machine traffic and server management functions to take place. You can create NIC bonds in XenCenter from the NICs tab or from the server’s Networking tab. Use the network type Bonded Network.

Viewing available NICs

For each available NIC on a server, the following device properties are shown on the NICs tab:

   
NIC Identifies the physical NIC or internal virtual network.
MAC The MAC (Media Access Control) address of the NIC.
Link Status The connection status of the NIC: Connected or Disconnected.
Speed The data transfer rate of the NIC.
Duplex The duplexing mode of the NIC: full or half.
Vendor, Device The NIC vendor and device names.
PCI Bus Path The PCI bus path for pass-through devices.

When you add a physical interface on your server, for example, a new Ethernet controller, it might not appear in the list on the NICs tab. If this situation happens, click Rescan on the NICs tab to force the server to scan for new cards.

To create a NIC bond

  1. Ensure that the NICs you want to bind together are not in use. Shut down any VMs with virtual network interfaces using the bonded NICs before creating the bond. After you have created the bond, reconnect the virtual network interfaces to an appropriate network.
  2. Select the server in the Resources pane then click the NICs tab and click Create Bond.
  3. Select the NICs you want to bond together. To select a NIC, select its check box in the list. Up to four NICs can be selected in this list. Clear the check box to deselect a NIC. To maintain a flexible and secure network, you can bond either two, three, or four NICs when vSwitch is the network stack. However, you can only bond two NICs when Linux bridge is the network stack.
  4. Under Bond mode, choose the type of bond:
    • Select Active-active to configure an active-active bond. With this bond, traffic is balanced between the bonded NICs. If one NIC within the bond fails, the host server’s network traffic automatically routes over the second NIC.
    • Select Active-passive to configure an active-passive bond, where traffic passes over only one of the bonded NICs. In this mode, the second NIC only becomes active if the active NIC fails, for example, if it loses network connectivity.

    • Select LACP with load balancing based on source MAC address to configure a LACP bond. With this bond, the outgoing NIC is selected based on MAC address of the VM from which the traffic originated. Use this option to balance traffic in an environment where you have several VMs on the same host. This option is not suitable if there are fewer virtual interfaces (VIFs) than NICs: as load balancing is not optimal because the traffic cannot be split across NICs.

    • Select LACP with load balancing based on IP and port of source and destination to configure a LACP bond. This bond uses the source IP address, source port, destination IP address, and destination port to allocate the traffic across the NICs. Use this option to balance traffic from VMs in an environment where the number of NICs exceeds the number of VIFs.

      Note:

      LACP bonding is only available for the vSwitch, whereas active-active and active-passive bonding modes are available for both the vSwitch and Linux bridge.

      For more information about the support for NIC bonds in Citrix Hypervisor, see the Networking.

  5. To use jumbo frames, set the Maximum Transmission Unit (MTU) to a value between 1500–9216.
  6. To have the new bonded network automatically added to any new VMs created using the New VM wizard, select the check box.
  7. Click Create to create the NIC bond and close the dialog box.

XenCenter automatically moves management and secondary interfaces from bonded NICs to the bond master when the new bond is created.

A server with its management interface on a bond is not permitted to join a pool. Reconfigure the server’s management interface and move it back on to a physical NIC before it can join a pool.

Deleting a NIC bond

If reverting a server to a non-bonded configuration, be aware of the following requirements:

  • As when creating a bond, all virtual machines with virtual network interfaces that use the bond must be shut down before destroying the bond. After reverting to a non-bonded configuration, reconnect the virtual network interfaces to an appropriate network.
  • Move the management interface to another NIC using the Management interfaces dialog box before you delete the bond, otherwise connections to the server (including XenCenter) are dropped.

To delete a bond

  1. Select the server in the Resources pane then click the NICs tab.
  2. Click Delete Bond.

Dedicating a NIC to a specific function

You can assign IP addresses to NICs to dedicate a NIC to a specific function, such as storage or other types of network traffic. For more information, see Configuring IP Addresses.

Configuring NICs