Configuring community alias

As a cluster administrator, you can configure a community alias and use it across different advertisements.

About the community custom resource

To simplify BGP configuration, define named aliases for community values by using the community custom resource. You can reference these aliases when advertising ipAddressPools with the BGPAdvertisement resource.

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

note

The community CRD applies only to BGPAdvertisement.

MetalLB community custom resource

Field	Type	Description
metadata.name	string	Specifies the name for the community.
metadata.namespace	string	Specifies the namespace for the community. Specify the same namespace that the MetalLB Operator uses.
spec.communities	string	Specifies a list of BGP community aliases that can be used in BGPAdvertisements. A community alias consists of a pair of name (alias) and value (number:number). Link the BGPAdvertisement to a community alias by referring to the alias name in its spec.communities field.

CommunityAlias

Field	Type	Description
name	string	The name of the alias for the community.
value	string	The BGP community value corresponding to the given name.

Configure MetalLB with a BGP advertisement and community alias

To advertise an IPAddressPool by using the BGP protocol, configure MetalLB with a community alias. This configuration sets the alias to the numeric value of the NO_ADVERTISE community.

In the following example, the peer BGP router doc-example-peer-community receives one 203.0.113.200/32 route and one fc00:f853:ccd:e799::1/128 route for each load-balancer IP address that MetalLB assigns to a service. A community alias is configured with the NO_ADVERTISE community.

Prerequisites

• Install the OpenShift CLI (oc)
• Log in as a user with cluster-admin privileges.

Procedure

1. Create an IP address pool.
   1. Create a file, such as ipaddresspool.yaml, with content like the following example:

      apiVersion: metallb.io/v1beta1
      kind: IPAddressPool
      metadata:
        namespace: metallb-system
        name: doc-example-bgp-community
      spec:
        addresses:
          - 203.0.113.200/30
          - fc00:f853:ccd:e799::/124

   2. Apply the configuration for the IP address pool:

      $ oc apply -f ipaddresspool.yaml

2. Create a community alias named community1.

   apiVersion: metallb.io/v1beta1
   kind: Community
   metadata:
     name: community1
     namespace: metallb-system
   spec:
     communities:
       - name: NO_ADVERTISE
         value: '65535:65282'

3. Create a BGP peer named doc-example-bgp-peer.
   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-bgp-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

4. Create a BGP advertisement with the community alias.

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

      apiVersion: metallb.io/v1beta1
      kind: BGPAdvertisement
      metadata:
        name: bgp-community-sample
        namespace: metallb-system
      spec:
        aggregationLength: 32
        aggregationLengthV6: 128
        communities:
          - NO_ADVERTISE
        ipAddressPools:
          - doc-example-bgp-community
        peers:
          - doc-example-peer

      where:

      NO_ADVERTISE: Specifies the CommunityAlias.name here and not the community custom resource (CR) name.

   2. Apply the configuration:

      $ oc apply -f bgpadvertisement.yaml