Chapter 9. Postinstallation tasks

• You need to modify the br-ex bridge after you installed the cluster.
• You need to modify the maximum transmission unit (MTU) for your cluster.
• You need to update DNS values.
• You need to modify attributes for a different bond interface, such as MIImon (Media Independent Interface Monitor), bonding mode, or Quality of Service (QoS).
• You need to enable Link Layer Discovery Protocol (LLDP) to discover and troubleshoot switch connectivity.

Prerequisites

• You have installed the Kubernetes NMState Operator.
• You have identified the specific nodes where you want to apply the policy.

Procedure

• Create a NodeNetworkConfigurationPolicy (NNCP) CR and define a customized br-ex bridge network configuration. The br-ex NNCP CR must include the OVN-Kubernetes masquerade IP address and subnet of your network. The example NNCP CR includes default values in the ipv4.address.ip and ipv6.address.ip parameters. You can set the masquerade IP address in the ipv4.address.ip, ipv6.address.ip, or both parameters.

  Important

  As a post-installation task, you cannot change the primary IP address of the customized br-ex bridge. If you want to convert your single-stack cluster network to a dual-stack cluster network, you can add or change a secondary IPv6 address in the NNCP CR, but the existing primary IP address cannot be changed.

  apiVersion: nmstate.io/v1
  kind: NodeNetworkConfigurationPolicy
  metadata:
    name: worker-0-br-ex
  spec:
    nodeSelector:
      kubernetes.io/hostname: worker-0
    desiredState:
      interfaces:
      - name: enp2s0
        type: ethernet
        state: up
        mtu: 9000
        ipv4:
          enabled: false
        ipv6:
          enabled: false
      - name: br-ex
        type: ovs-bridge
        state: up
        ipv4:
          enabled: false
          dhcp: false
        ipv6:
          enabled: false
          dhcp: false
        bridge:
          options:
            mcast-snooping-enable: true
          port:
          - name: enp2s0
          - name: br-ex
      - name: br-ex
        type: ovs-interface
        state: up
        copy-mac-from: enp2s0
        mtu: 9000
        ipv4:
          enabled: true
          dhcp: true
          auto-route-metric: 48
          address:
          - ip: "169.254.0.2"
            prefix-length: 17
        ipv6:
          enabled: true
          dhcp: true
          auto-route-metric: 48
          address:
          - ip: "fd69::2"
          prefix-length: 112
  # ...

  where:

  metadata.name

  Specifies the name of the policy.

  interfaces.name

  Specifies the name of the interface.

  interfaces.type

  Specifies the type of ethernet.

  interfaces.state

  Specifies the requested state for the interface after creation.

  mtu

  To ensure network stability and performance, you must explicitly declare the MTU in the manifest for every interface. Do not rely on automatic MTU configuration. The MTU configured on a bridge port or VLAN-tagged interface must not exceed the maximum frame size supported by the attached physical medium. A mismatch causes packet fragmentation or connectivity loss.

  ipv4.enabled

  Disables IPv4 and IPv6 in this example.

  port.name

  Specifies the node NIC to which the bridge is attached.

  address.ip

  Shows the default IPv4 and IPv6 IP addresses. Ensure that you set the masquerade IPv4 and IPv6 IP addresses of your network.

  auto-route-metric

  Set the parameter to 48 to ensure the br-ex default route always has the highest precedence (lowest metric). This configuration prevents routing conflicts with any other interfaces automatically configured by the NetworkManager service.

Next steps

• Scaling compute nodes to apply the manifest object that includes a customized br-ex bridge to each compute node that exists in your cluster. For more information, see "Expanding the cluster" in the Additional resources section.