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Configuring hybrid networking

As a cluster administrator, you can configure the Red Hat OpenShift Networking OVN-Kubernetes network plugin to allow Linux and Windows nodes to host Linux and Windows workloads, respectively.

Configuring hybrid networking with OVN-Kubernetes

You can configure your cluster to use hybrid networking with the OVN-Kubernetes network plugin. This allows a hybrid cluster that supports different node networking configurations.

Prerequisites

  • Install the OpenShift CLI (oc).

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

  • Ensure that the cluster uses the OVN-Kubernetes network plugin.

Procedure

  1. To configure the OVN-Kubernetes hybrid network overlay, enter the following command:

    $ oc patch networks.operator.openshift.io cluster --type=merge \
  -p '{
    "spec":{
      "defaultNetwork":{
        "ovnKubernetesConfig":{
          "hybridOverlayConfig":{
            "hybridClusterNetwork":[
              {
                "cidr": "<cidr>",
                "hostPrefix": <prefix>
              }
            ]
          }
        }
      }
    }
  }'

    where:

    cidr

    Specify the CIDR configuration used for nodes on the additional overlay network. This CIDR must not overlap with the cluster network CIDR.

    hostPrefix

    Specifies the subnet prefix length to assign to each individual node. For example, if hostPrefix is set to 23, then each node is assigned a /23 subnet out of the given cidr, which allows for 510 (2^(32 - 23) - 2) pod IP addresses. If you are required to provide access to nodes from an external network, configure load balancers and routers to manage the traffic.

    Example output
    network.operator.openshift.io/cluster patched

  2. To confirm that the configuration is active, enter the following command. It can take several minutes for the update to apply.

    $ oc get network.operator.openshift.io -o jsonpath="{.items[0].spec.defaultNetwork.ovnKubernetesConfig}"

Hiding until WMCO 10.16 GAs. Replace in step 1 after where: list

Windows Server Long-Term Servicing Channel (LTSC): Windows Server 2019 is not supported on clusters with a custom hybridOverlayVXLANPort value because this Windows server version does not support selecting a custom VXLAN port.

Additional resources