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As a cluster administrator, you can add, modify, and delete Bidirectional Forwarding Detection (BFD) profiles. The MetalLB Operator uses the BFD profile custom resources to identify which BGP sessions use BFD to provide faster path failure detection than BGP alone provides.

About the BFD profile custom resource

The fields for the BFD profile custom resource are described in the following table.

Table 1. BFD profile custom resource
Field Type Description

metadata.name

string

Specifies the name for the BFD profile custom resource.

metadata.namespace

string

Specifies the namespace for the BFD profile custom resource.

spec.detectMultiplier

integer

Specifies the detection multiplier to determine packet loss. The remote transmission interval is multiplied by this value to determine the connection loss detection timer.

For example, when the local system has the detect multiplier set to 3 and the remote system has the transmission interval set to 300, the local system detects failures only after 900 ms without receiving packets.

The range is 2 to 255. The default value is 3.

spec.echoMode

boolean

Specifies the echo transmission mode. If you are not using distributed BFD, echo transmission mode works only when the peer is also FRR. The default value is false and echo transmission mode is disabled.

When echo transmission mode is enabled, consider increasing the transmission interval of control packets to reduce bandwidth usage. For example, consider increasing the transmit interval to 2000 ms.

spec.echoInterval

integer

Specifies the minimum transmission interval, less jitter, that this system uses to send and receive echo packets. The range is 10 to 60000. The default value is 50 ms.

spec.minimumTtl

integer

Specifies the minimum expected TTL for an incoming control packet. This field applies to multi-hop sessions only.

The purpose of setting a minimum TTL is to make the packet validation requirements more stringent and avoid receiving control packets from other sessions.

The default value is 254 and indicates that the system expects only one hop between this system and the peer.

spec.passiveMode

boolean

Specifies whether a session is marked as active or passive. A passive session does not attempt to start the connection. Instead, a passive session waits for control packets from a peer before it begins to reply.

Marking a session as passive is useful when you have a router that acts as the central node of a star network and you want to avoid sending control packets that you do not need the system to send.

The default value is false and marks the session as active.

spec.receiveInterval

integer

Specifies the minimum interval that this system is capable of receiving control packets. The range is 10 to 60000. The default value is 300 ms.

spec.transmitInterval

integer

Specifies the minimum transmission interval, less jitter, that this system uses to send control packets. The range is 10 to 60000. The default value is 300 ms.

Configuring a BFD profile

As a cluster administrator, you can add a BFD profile and configure a BGP peer to use the profile. BFD provides faster path failure detection than BGP alone.

Prerequisites
  • Install the OpenShift CLI (oc).

  • Log in as a user with cluster-admin privileges.

Procedure
  1. Create a file, such as bfdprofile.yaml, with content like the following example:

    apiVersion: metallb.io/v1beta1
    kind: BFDProfile
    metadata:
      name: doc-example-bfd-profile-full
      namespace: metallb-system
    spec:
      receiveInterval: 35
      transmitInterval: 35
      detectMultiplier: 3
      echoInterval: 35
      echoMode: true
      passiveMode: true
      minimumTtl: 10
  2. Apply the configuration for the BFD profile:

    $ oc apply -f bfdprofile.yaml

Next steps