1. Documentation
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Use cases for a secondary network

You can use a secondary network in situations where you require network isolation, including data plane and control plane separation.

Isolating network traffic is useful for the following performance and security reasons:

  • Performance

    Traffic management: You can send traffic on two different planes to manage how much traffic is along each plane.

  • Security

    Network isolation: You can send sensitive traffic onto a network plane that is managed specifically for security considerations, and you can separate private data that must not be shared between tenants or customers.

All of the pods in the cluster still use the cluster-wide default network to maintain connectivity across the cluster. Every pod has an eth0 interface that is attached to the cluster-wide pod network. You can view the interfaces for a pod by using the oc exec -it <pod_name> -- ip a command. If you add secondary network interfaces that use the Multus Container Network Interface (CNI). These secondary networks are named net1, net2, and so on.

To attach secondary network interfaces to a pod, you must create configurations that define how the interfaces are attached. Use either a UserDefinedNetwork custom resource (CR) or a NetworkAttachmentDefinition CR to specify each interface. A CNI configuration inside each of these CRs defines how that interface is created.

Secondary networks in OKD

OKD provides the following CNI plugins for creating secondary networks in your cluster:

Additional resources