Change Subnet CIDR¶

If a subnet CIDR is created that conflicts or does not meet expectations, it can be modified by following the steps in this document.

After modifying the subnet CIDR, the previously created Pods will not be able to access the network properly and need to be rebuilt. Careful consideration is recommended before operating。This document is only for business subnet CIDR changes, if you need to Change the Join subnet CIDR, please refer to Change Join CIDR.

Edit Subnet¶

Use kubectl edit to modify cidrBlock，gateway and excludeIps.

kubectl edit subnet test-subnet

Rebuild all Pods under this Subnet¶

Take the subnet binding test Namespace as example:

for pod in $(kubectl get pod --no-headers -n "$ns" --field-selector spec.restartPolicy=Always -o custom-columns=NAME:.metadata.name,HOST:spec.hostNetwork | awk '{if ($2!="true") print $1}'); do
  kubectl delete pod "$pod" -n test --ignore-not-found
done

If only the default subnet is used, you can delete all Pods that are not in host network mode using the following command:

for ns in $(kubectl get ns --no-headers -o custom-columns=NAME:.metadata.name); do
  for pod in $(kubectl get pod --no-headers -n "$ns" --field-selector spec.restartPolicy=Always -o custom-columns=NAME:.metadata.name,HOST:spec.hostNetwork | awk '{if ($2!="true") print $1}'); do
    kubectl delete pod "$pod" -n "$ns" --ignore-not-found
  done
done

Change Default Subnet Settings¶

If you are modifying the CIDR for the default Subnet, you also need to change the args of the kube-ovn-controller Deployment:

args:
- --default-cidr=10.17.0.0/16
- --default-gateway=10.17.0.1
- --default-exclude-ips=10.17.0.1

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