v1.10 MaxLength validation breaks machine creation with large ignition config

[networkhell]

What steps did you take and what happened?

After upgrading to cluster-api v1.10.1, specifying an ignition config in spec.ignition.containerLinuxConfig.additionalConfig in manifests referencing one of the following crds:
kubeadmconfigs.bootstrap.cluster.x-k8s.io
kubeadmconfigtemplates.bootstrap.cluster.x-k8s.io
kubeadmcontrolplanes.controlplane.cluster.x-k8s.io
kubeadmcontrolplanetemplates.controlplane.cluster.x-k8s.io

with a size above 10240 bytes will prevent machines from being created or updated.

What did you expect to happen?

I expect my machines to be created / updated. So the MaxLength validation should be set to sane limit. I guess this depends on a.) the cloud provider and b.) ignition spec itself.
I will try to provide a.) for kolla installed openstack with default values.

As already discussed on cluster-api slack it would be great if we could provide large ignition configs via Secret or ConfigMap. But this should not necessarily be the scope of this issue.

Cluster API version

v1.10.1 for core, kubeadm-bootstrap and kubeadm-control-plane
v0.12.3 for CAPO

Kubernetes version

v1.32.4

Anything else you would like to add?

Logs from capi-controller-manager

E0508 09:58:58.505422       1 controller.go:347] "Reconciler error" err="failed to sync replicas: failed to clone bootstrap configuration from KubeadmConfigTemplate test01-dev-nsc01/test01-dev-nsc01-test01-dev-nsc01-node-muc5-b-xmk6f while creating a machine: KubeadmConfig.bootstrap.cluster.x-k8s.io \"test01-dev-nsc01-node-muc5-b-qljnw-cr6xw-ddwfw\" is invalid: spec.ignition.containerLinuxConfig.additionalConfig: Too long: may not be more than 10240 bytes" controller="machineset" controllerGroup="cluster.x-k8s.io" controllerKind="MachineSet" MachineSet="test01-dev-nsc01/test01-dev-nsc01-node-muc5-b-qljnw-cr6xw" namespace="test01-dev-nsc01" name="test01-dev-nsc01-node-muc5-b-qljnw-cr6xw" reconcileID="5ed0acd9-6546-4dd4-8334-dd21c1515419"

Label(s) to be applied

/kind bug
One or more /area label. See https://github.com/kubernetes-sigs/cluster-api/labels?q=area for the list of labels.

[chrischdi]

/priority important-soon
/triage accepted

Next step: Identify what new max value is suitable.

xref: https://kubernetes.slack.com/archives/C8TSNPY4T/p1746706504153769

[chrischdi]

/help

[k8s-ci-robot]

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