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Multus

Using Multus​

Multus CNI is a CNI Plugin that enables attaching multiple network interfaces to pods. Multus does not replace CNI Plugins, instead it acts as a CNI Plugin multiplexer. Multus is useful in certain use cases, especially when pods are network intensive and require extra network interfaces that support dataplane acceleration techniques such as SR-IOV.

Multus can not be deployed standalone. It always requires at least one conventional CNI Plugin that fulfills the Kubernetes cluster network requirements. That CNI Plugin becomes the default for Multus, and will be used to provide the primary interface for all pods.

To enable Multus, specify multus as the first list entry in the cni configuration file key, followed by the name of the plugin you want to use alongside Multus (or none if you will provide your own default plugin). Note that multus must always be in the first position of the list. For example, to use Multus with Canal as the primary CNI Plugin:

# /etc/rancher/rke2/config.yaml
cni:
- multus
- canal

For more information about Multus, refer to the multus-cni documentation.

Using Multus with Cilium​

Version Gate

Disabling the exclusive flag is not required starting with November 2025 releases: v1.31.14+rke2r1, v1.32.10+rke2r1,v1.33.6+rke2r1 and v1.34.2+rke2r1.

To use Cilium with Multus the exclusive config needs to be disabled. You can do this by using the following HelmChartConfig:

# /var/lib/rancher/rke2/server/manifests/rke2-cilium-config.yaml
---
apiVersion: helm.cattle.io/v1
kind: HelmChartConfig
metadata:
  name: rke2-cilium
  namespace: kube-system
spec:
  valuesContent: |-
    cni:
      exclusive: false

Using Multus with the containernetworking plugins​

Any CNI Plugin can be used as secondary CNI Plugin for Multus to provide additional network interfaces attached to a pod. However, it is most common to use the CNI Plugins maintained by the Kubernetes ContainerNetworking team (bridge, host-device, macvlan, etc) as secondary CNI Plugins for Multus. The Kubernetes ContainerNetworking team plugins are automatically deployed when installing Multus. For more information about these plugins, refer to the ContainerNetworking Plugins documentation.

To use any of these plugins, a proper NetworkAttachmentDefinition object will need to be created to define the configuration of the secondary network. The definition is then referenced by pod annotations, which Multus will use to provide extra interfaces to that pod. An example using the macvlan CNI Pllugin with Multus is available in the multus-cni repo.

Multus IPAM plugin options​

host-local IPAM plugin allocates ip addresses out of a set of address ranges. It stores the state locally on the host filesystem, therefore ensuring uniqueness of IP addresses on a single host. Therefore, we don't recommend it for multi-node clusters. This IPAM plugin does not require any extra deployment. For more information: https://www.cni.dev/plugins/current/ipam/host-local/.

Using Multus with the "thick plugin" option (Experimental)​

Version Gate

This feature is available starting with versions v1.31.11+rke2r1, v1.32.7+rke2r1 and v1.33.3+rke2r1.

rke2 now supports deploying Multus with a new architecture called "thick plugin".

You can enable with this HelmChartConfig:

# /var/lib/rancher/rke2/server/manifests/rke2-multus-config.yaml
---
apiVersion: helm.cattle.io/v1
kind: HelmChartConfig
metadata:
  name: rke2-multus
  namespace: kube-system
spec:
  valuesContent: |-
    thickPlugin:
      enabled: true

Enabling Multus Dynamic Networks Controller​

One use case for using Multus "thick plugin" is to deploy the Dynamic Networks Controller. This is done through the following HelmChartConfig:

# /var/lib/rancher/rke2/server/manifests/rke2-multus-config.yaml
---
apiVersion: helm.cattle.io/v1
kind: HelmChartConfig
metadata:
  name: rke2-multus
  namespace: kube-system
spec:
  valuesContent: |-
    thickPlugin:
      enabled: true
    dynamicNetworksController:
      enabled: true
note

The Dynamic Networks Controller can be deployed only with Multus in "thick plugin" mode.

Using Multus with SR-IOV​

Using the SR-IOV CNI with Multus can help with data-plane acceleration use cases, providing an extra interface in the pod that can achieve very high throughput. Complete deployment steps, prerequisites, and hardware compatibility details can be found in the SR-IOV Network Operator Quickstart Guide

For fully validated configurations and enterprise-grade infrastructure support for SR-IOV in RKE2, refer to SUSE Telco Cloud