Chapter 9. Configuring network bonds using the web console

Learn how network bonding works and configure network bonds in the RHEL 8 web console.

Note

The RHEL 8 web console is build on top of the NetworkManager service.

For details, see Getting started with NetworkManager for managing networking.

Prerequisites

9.1. Understanding network bonding

Network bonding is a method to combine or aggregate network interfaces to provide a logical interface with higher throughput or redundancy.

The active-backup, balance-tlb, and balance-alb modes do not require any specific configuration of the network switch. However, other bonding modes require configuring the switch to aggregate the links. For example, Cisco switches requires EtherChannel for modes 0, 2, and 3, but for mode 4, the Link Aggregation Control Protocol (LACP) and EtherChannel are required.

For further details, see the documentation of your switch and Linux Ethernet Bonding Driver HOWTO.

Important

Certain network bonding features, such as the fail-over mechanism, do not support direct cable connections without a network switch. For further details, see the Is bonding supported with direct connection using crossover cables? KCS solution.

9.2. Bond modes

In RHEL 8 there are several mode options. Each mode option is characterize by specific load balancing and fault tolerance. The behavior of the bonded interfaces depends upon the mode. The bonding modes provide fault tolerance, load balancing or both.

Load balancing modes

  • Round Robin: Sequentially transmit packets from the first available interface to the last one.

Fault tolerance modes

  • Active Backup: Only when the primary interface fails, one of a backup interfaces replaces it. Only a MAC address used by active interface is visible.
  • Broadcast: All transmissions are sent on all interfaces.

    Note

    Broadcasting significantly increases network traffic on all the bonded interfaces.

Fault tolerance and load balancing modes

  • XOR: The destination MAC addresses are distributed equally between interfaces with a modulo hash. Each interface then serves the same group of MAC addresses.
  • 802.3ad: Sets an IEEE 802.3ad dynamic link aggregation policy. Creates aggregation groups that share the same speed and duplex settings. Transmits and receives on all interfaces in the active aggregator.

    Note

    This mode requires a switch that is 802.3ad compliant.

  • Adaptive transmit load balancing: The outgoing traffic is distributed according to the current load on each interface. Incoming traffic is received by the current interface. If the receiving interface fails, another interface takes over the MAC address of the failed one.
  • Adaptive load balancing: Includes transmit and receive load balancing for IPv4 traffic.

    Receive load balancing is achieved through Address Resolution Protocol (ARP) negotiation, therefore, it is necessary to set Link Monitoring to ARP in the bond’s configuration.

9.3. Configuring a network bond using the RHEL web console

This section describes how to configure a network bond using the RHEL web console.

Prerequisites

Procedure

  1. Select the Networking tab in the navigation on the left side of the screen.
  2. Click Add bond in the Interfaces section.
  3. Enter the name of the bond device you want to create.
  4. Select the interfaces that should be members of the bond.
  5. Select the mode of the bond.

    If you select Active backup, the web console shows the additional field Primary in which you can select the preferred active device.

  6. Set the link monitoring mode. For example, when you use the Adaptive load balancing mode, set it to ARP.
  7. Optional: Adjust the monitoring interval, link up delay, and link down delay settings. Typically, you only change the defaults for troubleshooting purposes.

    bond settings
  8. Click Apply.
  9. By default, the bond uses a dynamic IP address. If you want to set a static IP address:

    1. Click the name of the bond in the Interfaces section.
    2. Click Edit next to the protocol you want to configure.
    3. Select Manual next to Addresses, and enter the IP address, prefix, and default gateway.
    4. In the DNS section, click the + button, and enter the IP address of the DNS server. Repeat this step to set multiple DNS servers.
    5. In the DNS search domains section, click the + button, and enter the search domain.
    6. If the interface requires static routes, configure them in the Routes section.

      bond team bridge vlan.ipv4
    7. Click Apply

Verification

  1. Select the Networking tab in the navigation on the left side of the screen, and check if there is incoming and outgoing traffic on the interface:

    bond verify
  2. Temporarily remove the network cable from the host.

    Note that there is no method to properly test link failure events using software utilities. Tools that deactivate connections, such as the web console, show only the bonding driver’s ability to handle member configuration changes and not actual link failure events.

  3. Display the status of the bond:

    # cat /proc/net/bonding/bond0

9.4. Adding interfaces to the bond using the web console

Network bonds can include multiple interfaces and you can add or remove any of them at any time.

Learn how to add a network interface to an existing bond.

Prerequisites

Procedure

  1. Log in to the web console.

    For details, see Logging in to the web console.

  2. Open Networking.
  3. In the Interfaces table, click on the bond you want to configure.
  4. In the bond settings screen, scroll down to the table of members (interfaces).
  5. Click the Add member drop down icon.
  6. Select the interface in the drop down menu and click it.

Verification steps

  • Check that the selected interface appeared in the Interface members table in the bond settings screen.

9.5. Removing or disabling an interface from the bond using the web console

Network bonds can include multiple interfaces. If you need to change a device, you can remove or disable particular interfaces from the bond, which will work with the rest of the active interfaces.

To stop using an interface included in a bond, you can:

  • Remove the interface from the bond.
  • Disable the interface temporarily. The interface stays a part of the bond, but the bond will not use it until you enable it again.

Prerequisites

Procedure

  1. Log in to the RHEL web console. For details, see Logging in to the web console.
  2. Open Networking.
  3. Click the bond you want to configure.
  4. In the bond settings screen, scroll down to the table of ports (interfaces).
  5. Select the interface and remove or disable it:

    • To remove the interface, click the - button.
    • To disable or enable the interface, toggle the switch next to the selected interface.

Based on your choice, the web console either removes or disables the interface from the bond and you can see it back in the Networking section as a standalone interface.

9.6. Removing or disabling a bond using the web console

Remove or disable a network bond using the web console. If you disable the bond, the interfaces stay in the bond, but the bond will not be used for network traffic.

Prerequisites

  • There is an existing bond in the web console.

Procedure

  1. Log in to the web console.

    For details, see Logging in to the web console.

  2. Open Networking.
  3. Click the bond you want to remove.
  4. In the bond settings screen, you can disable or enable the bond by toggling a switcher or click the Delete button to remove the bond permanently.

    cockpit remove bond

Verification steps

  • Go back to Networking and verify that all the interfaces from the bond are now standalone interfaces.