Allow diskSetup to include partition layout

[Xartos]

What would you like to be added (User Story)?

As a cluster administrator I would like to be able to setup nodes that has a single disk with multiple partitions

Detailed Description

Currently there's no way to have a single node VM and split its disk into multiple partitions since this field is only a boolean.
However, the cloud-init documentation says that this can either be a bool (to set up the disk as a single partition) or a list that describes the partition layout, reference.

So my proposal would be to allow this field to be either a boolean or a list. Alternatively add another field that describes the layout that can be merged with the existing field when generating the cloud-init user-data file.

Anything else you would like to add?

No response

Label(s) to be applied

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

[fabriziopandini]

/triage accepted
defining a field that can be either a list or a boolean requires some work in golang, but it is something that we can explore

/help

[k8s-ci-robot]

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In response to this:

/triage accepted
defining a field that can be either a list or a boolean requires some work in golang, but it is something that we can explore

/help

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[ansh-wal]

@fabriziopandini I can pick this up.

[sbueringer]

I'm not sure if we can make this work without a breaking change to our go API structs (which would mean we have to wait until v1beta2)

[fabriziopandini]

/priority backlog

[miltalex]

@fabriziopandini I was curious if that is something that can be done now, or there are still blockers? I would like to have a look into it when I find a bit of time.

[sbueringer]

To the best of my knowledge bool or list is not possible with crds (https://kubernetes.io/docs/tasks/extend-kubernetes/custom-resources/custom-resource-definitions/#intorstring cc @JoelSpeed). So I think we have to express this in a different way in our crd

Also seems like the list has different types in it

layout:
- [33,82]
- 66

I think that's also not supported in CRDs

[JoelSpeed]

Yeah that wouldn't be a structural schema, but you could represent the choices in a kube like way using a discriminated union, the yaml version would look something like:

diskLayout:
  type: Unpartitioned | SinglePartition | Custom
  custom:
  - sizePercentage: 0 < int < 100
    partitionType:  int (? Looking at the docs I think this is an int but not sure)