How to prevent NetworkManager from interfering with Kubernetes cluster networking interfaces

This document (000020017) is provided subject to the disclaimer at the end of this document.

Situation

Issue

NetworkManager can interfere with Kubernetes cluster networking, by attempting to manage interfaces created on cluster nodes by the CNI (Container Network Interface) plugin. This article details how to prevent NetworkManager from managing CNI interfaces, in clusters running with the Canal, Calico, Flannel or Weave CNI plugins.

Pre-requisites

A Linux node with NetworkManager running

Resolution

Create the file /etc/NetworkManager/conf.d/cni.conf on each of the Linux nodes in the cluster, with the content below, depending upon the CNI plugin used:

Canal:

[keyfile]
unmanaged-devices=interface-name:flannel.1;interface-name:cali*

Calico:

[keyfile]
unmanaged-devices=interface-name:cali*;interface-name:tunl*;interface-name:vxlan.calico

Flannel:

[keyfile]
unmanaged-devices=interface-name:flannel.1;interface-name:veth*;interface-name:cni0

Weave:

[keyfile]
unmanaged-devices=interface-name:weave;interface-name:datapath;interface-name:veth*;interface-name:vxlan-*

Restart the NetworkManager service:
```
systemctl restart NetworkManager
```

Disclaimer

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