By default, Kubernetes allows for a single network (primary network) to be connected to a POD. Kubernetes network attachment definition custom resources enhance this capability, and allow users to attach multi-networks for POD, a primary network which runs all of Kubernetes services and one or more secondary networks which are typically used for high performance. The cluster network CNI plugin (primary plugin) is satisfying Kubernetes’ networking requirements. Below is a list of well known cluster network CNI providers:
The Multus CNI plugin enables attaching multiple network interfaces to pods. Multus is acting as a "meta-plugin", a CNI plugin that can call multiple other CNI plugins.