[Bug] IPv6 with AutoMode incorrectly returns error when core addons are not specified

[saurav-agarwalla]

What were you trying to accomplish?

Creating an IPv6 enabled cluster with EKS AutoMode results in incorrect validation errors for missing core addons. With EKS Auto Mode, core addons are not mandatory. We should relax this validation when EKS Auto Mode is enabled.

What happened?

Error: the default core addons must be defined for IPv6; missing addon(s): vpc-cni, coredns, kube-proxy

How to reproduce it?

➜  ~ eksctl create cluster -f eksctl.yaml
Error: the default core addons must be defined for IPv6; missing addon(s): vpc-cni, coredns, kube-proxy
➜  ~
➜  ~ cat eksctl.yaml
apiVersion: eksctl.io/v1alpha5
kind: ClusterConfig

metadata:
  name: eks-auto-ipv6
  region: us-west-2

kubernetesNetworkConfig:
  ipFamily: IPv6

autoModeConfig:
  enabled: true

Logs

Anything else we need to know?

N/A

Versions

$ eksctl info
eksctl version: 0.197.0-dev+e96028b65.2024-12-03T11:01:49Z
kubectl version: v1.31.1
OS: darwin

[github-actions]

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[saurav-agarwalla]

While we are at this, we should also add an integration test for IPv6 with auto mode: https://github.com/eksctl-io/eksctl/blob/7991e07ef91333c0a34667e84ba75c0d3a5efc1e/integration/tests/auto_mode/auto_mode_test.go