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 type	Type value	Allowed bridge types	Allowed 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 vSwitch (OVS) bonding options

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

bond_mode=balance-slb: Source load balancing (slb) balances flows based on source MAC address and output VLAN, with periodic rebalancing as traffic patterns change. When you configure a bond with the balance-slb bonding option, there is no configuration required on the remote switch. The Networking service (neutron) assigns each source MAC and VLAN pair to a link and transmits all packets from that MAC and VLAN through that link. A simple hashing algorithm based on source MAC address and VLAN number is used, with periodic rebalancing as traffic patterns change. The balance-slb 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: When you configure a bond using active-backup bond mode, the Networking service keeps one NIC in standby. 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 switch 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: Set active-backup as the bond mode if LACP fails.
other_config:lacp-time=[fast | slow]: Set the LACP heartbeat to one 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 (milliseconds).
bond_updelay=1000: Set the interval (milliseconds) that a link must be up to be activated to prevent flapping.
other_config:bond-rebalance-interval=10000: Set the interval (milliseconds) that flows are rebalancing between bond members. Set this value to zero to disable flow rebalancing between bond members.

12.4. Using Link Aggregation Control Protocol (LACP) with Open vSwitch (OVS) bonding modes

You can use bonds with the optional Link Aggregation Control Protocol (LACP). LACP is a negotiation protocol that creates a dynamic bond for load balancing and fault tolerance.

Use the following table to understand support compatibility for OVS kernel and OVS-DPDK bonded interfaces in conjunction with LACP options.

Important

The OVS/OVS-DPDK balance-tcp mode is available as a technology preview only.

Important

On control and storage networks, Red Hat recommends that you use Linux bonds with VLAN and LACP, because OVS bonds carry the potential for control plane disruption that can occur when OVS or the neutron agent is restarted for updates, hot fixes, and other events. The Linux bond/LACP/VLAN configuration provides NIC management without the OVS disruption potential.

Table 12.2. LACP options for OVS kernel and OVS-DPDK bond modes
Objective	OVS bond mode	Compatible LACP options	Notes
High availability (active-passive)	`active-backup`	`active`, `passive`, or `off`
Increased throughput (active-active)	`balance-slb`	`active`, `passive`, or `off`	Performance is affected by extra parsing per packet. There is a potential for vhost-user lock contention.
Increased throughput (active-active)	`balance-tcp`	`active` or `passive`	Tech preview only. Not recommended for use in production. Recirculation needed for L4 hashing has a performance impact. As with balance-slb, performance is affected by extra parsing per packet and there is a potential for vhost-user lock contention. LACP must be enabled.

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 on OVS bridge. 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}

Chapter 12. Network interface bonding

12.1. Network interface bonding for overcloud nodes

12.2. Creating Open vSwitch (OVS) bonds

12.3. Open vSwitch (OVS) bonding options

12.4. Using Link Aggregation Control Protocol (LACP) with Open vSwitch (OVS) bonding modes

12.5. Creating Linux bonds

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