How to configure Calico Node IP Autodetection with Specific CIDRs

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Environment

Rancher 2.x

RKE2

Situation

In environments where Kubernetes nodes (e.g., RKE2) have multiple network interfaces or IP addresses, it's often necessary to explicitly tell the Container Network Interface (CNI), such as Calico, which IP address to use for its internal communication and pod networking. If Calico automatically selects an incorrect interface (e.g., the interface of a management network instead of the intended data network), it can lead to network connectivity issues for pods or between nodes.

Resolution

Add the below config in the downstream cluster under the Additional Manifest tab in the Rancher UI during the creation to adjust the auto detection method for Calico:

apiVersion: helm.cattle.io/v1
kind: HelmChartConfig
metadata:
  name: rke2-calico
  namespace: kube-system
spec:
  valuesContent: |-
    installation:
      calicoNetwork:
        nodeAddressAutodetectionV4:
          firstFound: false
          cidrs:
            - "192.168.1.0/24" # Replace with your target CIDR

Status

Top Issue

Additional Information

Configure IP autodetection | Calico Documentation

Disclaimer

This Support Knowledgebase provides a valuable tool for SUSE customers and parties interested in our products and solutions to acquire information, ideas and learn from one another. Materials are provided for informational, personal or non-commercial use within your organization and are presented "AS IS" WITHOUT WARRANTY OF ANY KIND.