Chapter 12. Network interface bonding

You can use various bonding options in your custom network configuration.

12.1. Network interface bonding for overcloud nodes

You can bundle multiple physical NICs together to form a single logical channel known as a bond. You can configure bonds to provide redundancy for high availability systems or increased throughput.

Red Hat OpenStack Platform supports Open vSwitch (OVS) kernel bonds, OVS-DPDK bonds, and Linux kernel bonds.

Table 12.1. Supported interface bonding types

Bond typeType valueAllowed bridge typesAllowed members

OVS kernel bonds

ovs_bond

ovs_bridge

interface

OVS-DPDK bonds

ovs_dpdk_bond

ovs_user_bridge

ovs_dpdk_port

Linux kernel bonds

linux_bond

ovs_bridge or linux_bridge

interface

Important

Do not combine ovs_bridge and ovs_user_bridge on the same node.

12.2. Creating Open vSwitch (OVS) bonds

You create OVS bonds in your network interface templates. For example, you can create a bond as part of an OVS user space bridge:

...
          params:
            $network_config:
              network_config:
              - type: ovs_user_bridge
                name: br-ex
                use_dhcp: false
                members:
                - type: ovs_dpdk_bond
                  name: dpdkbond0
                  mtu: 2140
                  ovs_options: {get_param: BondInterfaceOvsOptions}
                  rx_queue:
                    get_param: NumDpdkInterfaceRxQueues
                  members:
                  - type: ovs_dpdk_port
                    name: dpdk0
                    mtu: 2140
                    members:
                    - type: interface
                      name: p1p1
                  - type: ovs_dpdk_port
                    name: dpdk1
                    mtu: 2140
                    members:
                    - type: interface
                      name: p1p2

In this example, you create the bond from two DPDK ports.

The ovs_options parameter contains the bonding options. You can configure a bonding options in a network environment file with the BondInterfaceOvsOptions parameter:

parameter_defaults:
  BondInterfaceOvsOptions: "bond_mode=balance-slb"

12.3. Open vSwtich (OVS) bonding options

You can set various Open vSwitch (OVS) bonding options with the ovs_options heat parameter in your NIC template files.

Table 12.2. Bonding options

Option

Description

bond_mode=balance-slb

Balances flows based on source MAC address and output VLAN, with periodic rebalancing as traffic patterns change. Bonding with balance-slb allows a limited form of load balancing without the remote switch’s knowledge or cooperation. SLB assigns each source MAC and VLAN pair to a link and transmits all packets from that MAC and VLAN through that link. This mode uses a simple hashing algorithm based on source MAC address and VLAN number, with periodic rebalancing as traffic patterns change. This mode is similar to mode 2 bonds used by the Linux bonding driver. You can use this mode to provide load balancing even when the switch is not configured to use LACP.

bond_mode=active-backup

This mode offers active/standby failover where the standby NIC resumes network operations when the active connection fails. Only one MAC address is presented to the physical switch. This mode does not require any special switch support or configuration, and works when the links are connected to separate switches. This mode does not provide load balancing.

lacp=[active|passive|off]

Controls the Link Aggregation Control Protocol (LACP) behavior. Only certain switches support LACP. If your switch does not support LACP, use bond_mode=balance-slb or bond_mode=active-backup.

other-config:lacp-fallback-ab=true

Sets the LACP behavior to switch to bond_mode=active-backup as a fallback.

other_config:lacp-time=[fast|slow]

Set the LACP heartbeat to 1 second (fast) or 30 seconds (slow). The default is slow.

other_config:bond-detect-mode=[miimon|carrier]

Set the link detection to use miimon heartbeats (miimon) or monitor carrier (carrier). The default is carrier.

other_config:bond-miimon-interval=100

If using miimon, set the heartbeat interval in milliseconds.

bond_updelay=1000

Number of milliseconds a link must be up to be activated to prevent flapping.

other_config:bond-rebalance-interval=10000

Milliseconds between rebalancing flows between bond members. Set this value to zero to disable rebalancing flows between bond members.

12.5. Creating Linux bonds

You create linux bonds in your network interface templates. For example, you can create a linux bond that bond two interfaces:

...
          params:
            $network_config:
              network_config:
              - type: linux_bond
                name: bond1
                members:
                - type: interface
                  name: nic2
                - type: interface
                  name: nic3
                bonding_options: "mode=802.3ad lacp_rate=[fast|slow] updelay=1000 miimon=100"

The bonding_options parameter sets the specific bonding options for the Linux bond.

mode
Sets the bonding mode, which in the example is 802.3ad or LACP mode. For more information about Linux bonding modes, see "Upstream Switch Configuration Depending on the Bonding Modes" in the Red Hat Enterprise Linux 8 Configuring and Managing Networking guide.
lacp_rate
Defines whether LACP packets are sent every 1 second, or every 30 seconds.
updelay
Defines the minimum amount of time that an interface must be active before it is used for traffic. This minimum configuration helps to mitigate port flapping outages.
miimon
The interval in milliseconds that is used for monitoring the port state using the MIIMON functionality of the driver.

Use the following additional examples as guides to configure your own Linux bonds:

  • Linux bond set to active-backup mode with one VLAN:

    ....
              params:
                $network_config:
                  network_config:
                  - type: linux_bond
                    name: bond_api
                    bonding_options: "mode=active-backup"
                    use_dhcp: false
                    dns_servers:
                      get_param: DnsServers
                    members:
                    - type: interface
                      name: nic3
                      primary: true
                    - type: interface
                      name: nic4
    
                  - type: vlan
                    vlan_id:
                      get_param: InternalApiNetworkVlanID
                    device: bond_api
                    addresses:
                    - ip_netmask:
                        get_param: InternalApiIpSubnet
  • Linux bond set to 802.3ad LACP mode with one VLAN:

    ...
              params:
                $network_config:
                  network_config:
                -  type: ovs_bridge
                    name: br-tenant
                    use_dhcp: false
                    mtu: 9000
                    members:
                      - type: linux_bond
                        name: bond_tenant
                        bonding_options: "mode=802.3ad updelay=1000 miimon=100"
                        use_dhcp: false
                        dns_servers:
                          get_param: DnsServers
                        members:
                        - type: interface
                          name: p1p1
                          primary: true
                        - type: interface
                          name: p1p2
                      - type: vlan
                        device: bond_tenant
                        vlan_id: {get_param: TenantNetworkVlanID}
                        addresses:
                          -
                            ip_netmask: {get_param: TenantIpSubnet}