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Configuring MetalLB BGP peers

As a cluster administrator, you can add, modify, and delete Border Gateway Protocol (BGP) peers. The MetalLB Operator uses the BGP peer custom resources to identify which peers that MetalLB speaker pods contact to start BGP sessions. The peers receive the route advertisements for the load-balancer IP addresses that MetalLB assigns to services.

About the BGP peer custom resource

The fields for the BGP peer custom resource are described in the following table.

Table 1. MetalLB BGP peer custom resource
Field Type Description

metadata.name

string

Specifies the name for the BGP peer custom resource.

metadata.namespace

string

Specifies the namespace for the BGP peer custom resource.

spec.myASN

integer

Specifies the Autonomous System number for the local end of the BGP session. Specify the same value in all BGP peer custom resources that you add. The range is 0 to 4294967295.

spec.peerASN

integer

Specifies the Autonomous System number for the remote end of the BGP session. The range is 0 to 4294967295.

spec.peerAddress

string

Specifies the IP address of the peer to contact for establishing the BGP session.

spec.sourceAddress

string

Optional: Specifies the IP address to use when establishing the BGP session. The value must be an IPv4 address.

spec.peerPort

integer

Optional: Specifies the network port of the peer to contact for establishing the BGP session. The range is 0 to 16384.

spec.holdTime

string

Optional: Specifies the duration for the hold time to propose to the BGP peer. The minimum value is 3 seconds (3s). The common units are seconds and minutes, such as 3s, 1m, and 5m30s. To detect path failures more quickly, also configure BFD.

spec.keepaliveTime

string

Optional: Specifies the maximum interval between sending keep-alive messages to the BGP peer. If you specify this field, you must also specify a value for the holdTime field. The specified value must be less than the value for the holdTime field.

spec.routerID

string

Optional: Specifies the router ID to advertise to the BGP peer. If you specify this field, you must specify the same value in every BGP peer custom resource that you add.

spec.password

string

Optional: Specifies the MD5 password to send to the peer for routers that enforce TCP MD5 authenticated BGP sessions.

spec.passwordSecret

string

Optional: Specifies name of the authentication secret for the BGP Peer. The secret must live in the metallb namespace and be of type basic-auth.

spec.bfdProfile

string

Optional: Specifies the name of a BFD profile.

spec.nodeSelectors

object[]

Optional: Specifies a selector, using match expressions and match labels, to control which nodes can connect to the BGP peer.

spec.ebgpMultiHop

boolean

Optional: Specifies that the BGP peer is multiple network hops away. If the BGP peer is not directly connected to the same network, the speaker cannot establish a BGP session unless this field is set to true. This field applies to external BGP. External BGP is the term that is used to describe when a BGP peer belongs to a different Autonomous System.

The passwordSecret field is mutually exclusive with the password field, and contains a reference to a secret containing the password to use. Setting both fields results in a failure of the parsing.

Configuring a BGP peer

As a cluster administrator, you can add a BGP peer custom resource to exchange routing information with network routers and advertise the IP addresses for services.

Prerequisites

  • Install the OpenShift CLI (oc).

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

  • Configure MetalLB with a BGP advertisement.

Procedure

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

    apiVersion: metallb.io/v1beta2
kind: BGPPeer
metadata:
  namespace: metallb-system
  name: doc-example-peer
spec:
  peerAddress: 10.0.0.1
  peerASN: 64501
  myASN: 64500
  routerID: 10.10.10.10

  2. Apply the configuration for the BGP peer:

    $ oc apply -f bgppeer.yaml

Configure a specific set of BGP peers for a given address pool

This procedure illustrates how to:

  • Configure a set of address pools (pool1 and pool2).

  • Configure a set of BGP peers (peer1 and peer2).

  • Configure BGP advertisement to assign pool1 to peer1 and pool2 to peer2.

Prerequisites

  • Install the OpenShift CLI (oc).

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

Procedure

  1. Create address pool pool1.

    1. Create a file, such as ipaddresspool1.yaml, with content like the following example:

      apiVersion: metallb.io/v1beta1
kind: IPAddressPool
metadata:
  namespace: metallb-system
  name: pool1
spec:
  addresses:
    - 4.4.4.100-4.4.4.200
    - 2001:100:4::200-2001:100:4::400

    2. Apply the configuration for the IP address pool pool1:

      $ oc apply -f ipaddresspool1.yaml

  2. Create address pool pool2.

    1. Create a file, such as ipaddresspool2.yaml, with content like the following example:

      apiVersion: metallb.io/v1beta1
kind: IPAddressPool
metadata:
  namespace: metallb-system
  name: pool2
spec:
  addresses:
    - 5.5.5.100-5.5.5.200
    - 2001:100:5::200-2001:100:5::400

    2. Apply the configuration for the IP address pool pool2:

      $ oc apply -f ipaddresspool2.yaml

  3. Create BGP peer1.

    1. Create a file, such as bgppeer1.yaml, with content like the following example:

      apiVersion: metallb.io/v1beta2
kind: BGPPeer
metadata:
  namespace: metallb-system
  name: peer1
spec:
  peerAddress: 10.0.0.1
  peerASN: 64501
  myASN: 64500
  routerID: 10.10.10.10

    2. Apply the configuration for the BGP peer:

      $ oc apply -f bgppeer1.yaml

  4. Create BGP peer2.

    1. Create a file, such as bgppeer2.yaml, with content like the following example:

      apiVersion: metallb.io/v1beta2
kind: BGPPeer
metadata:
  namespace: metallb-system
  name: peer2
spec:
  peerAddress: 10.0.0.2
  peerASN: 64501
  myASN: 64500
  routerID: 10.10.10.10

    2. Apply the configuration for the BGP peer2:

      $ oc apply -f bgppeer2.yaml

  5. Create BGP advertisement 1.

    1. Create a file, such as bgpadvertisement1.yaml, with content like the following example:

      apiVersion: metallb.io/v1beta1
kind: BGPAdvertisement
metadata:
  name: bgpadvertisement-1
  namespace: metallb-system
spec:
  ipAddressPools:
    - pool1
  peers:
    - peer1
  communities:
    - 65535:65282
  aggregationLength: 32
  aggregationLengthV6: 128
  localPref: 100

    2. Apply the configuration:

      $ oc apply -f bgpadvertisement1.yaml

  6. Create BGP advertisement 2.

    1. Create a file, such as bgpadvertisement2.yaml, with content like the following example:

      apiVersion: metallb.io/v1beta1
kind: BGPAdvertisement
metadata:
  name: bgpadvertisement-2
  namespace: metallb-system
spec:
  ipAddressPools:
    - pool2
  peers:
    - peer2
  communities:
    - 65535:65282
  aggregationLength: 32
  aggregationLengthV6: 128
  localPref: 100

    2. Apply the configuration:

      $ oc apply -f bgpadvertisement2.yaml

Example BGP peer configurations

Example: Limit which nodes connect to a BGP peer

You can specify the node selectors field to control which nodes can connect to a BGP peer.

apiVersion: metallb.io/v1beta2
kind: BGPPeer
metadata:
  name: doc-example-nodesel
  namespace: metallb-system
spec:
  peerAddress: 10.0.20.1
  peerASN: 64501
  myASN: 64500
  nodeSelectors:
  - matchExpressions:
    - key: kubernetes.io/hostname
      operator: In
      values: [compute-1.example.com, compute-2.example.com]

Example: Specify a BFD profile for a BGP peer

You can specify a BFD profile to associate with BGP peers. BFD compliments BGP by providing more rapid detection of communication failures between peers than BGP alone.

apiVersion: metallb.io/v1beta2
kind: BGPPeer
metadata:
  name: doc-example-peer-bfd
  namespace: metallb-system
spec:
  peerAddress: 10.0.20.1
  peerASN: 64501
  myASN: 64500
  holdTime: "10s"
  bfdProfile: doc-example-bfd-profile-full

Deleting the bidirectional forwarding detection (BFD) profile and removing the bfdProfile added to the border gateway protocol (BGP) peer resource does not disable the BFD. Instead, the BGP peer starts using the default BFD profile. To disable BFD from a BGP peer resource, delete the BGP peer configuration and recreate it without a BFD profile. For more information, see BZ#2050824.

Example: Specify BGP peers for dual-stack networking

To support dual-stack networking, add one BGP peer custom resource for IPv4 and one BGP peer custom resource for IPv6.

apiVersion: metallb.io/v1beta2
kind: BGPPeer
metadata:
  name: doc-example-dual-stack-ipv4
  namespace: metallb-system
spec:
  peerAddress: 10.0.20.1
  peerASN: 64500
  myASN: 64500
---
apiVersion: metallb.io/v1beta2
kind: BGPPeer
metadata:
  name: doc-example-dual-stack-ipv6
  namespace: metallb-system
spec:
  peerAddress: 2620:52:0:88::104
  peerASN: 64500
  myASN: 64500

Next steps