Resolve IP range conflicts with K8s installations

Author: Jason De Paola

Updated: November 2024

Audience: Everyone

Environmental details: Self-hosted KOTS

Summary

There may be IP subnet conflicts where the self hosted machine is using the same IP range as KOTS.

The following patch YAML can be used to configure the IP adddress ranges of Pods and Services.

Note that the installer will attempt to default to 10.32.0.0/20 for Pods and 10.96.0.0/22 for Services.

If not available, the installer will attempt to find an available range with prefix bits of 20 and 22 respectively in the 10.32.0.0/16 or 10.0.0.0/8 address spaces.

apiVersion: cluster.kurl.sh/v1beta1
  kind: Installer
  metadata:
    name: "patch"
  spec:
    kubernetes:
      serviceCIDR: "<your custom subnet>"
    flannel:     
      podCIDR: "<your custom subnet>"

Save the above as a .yaml file (note being a yaml file the indentation is mandatory), and run the install follows:

curl -sSL https://k8s.kurl.sh/jama-k8s-standardkots | sudo bash -s installer-spec-file=[path to YAML patch]

Further Details on the above process can be found here:

https://kurl.sh/docs/install-with-kurl#select-examples-of-using-a-patch-yaml-file

Flannel specifics can be found here:

https://kurl.sh/docs/add-ons/flannel#custom-pod-subnet