Custom remote URL for user Data

[CYBERBUGJR]

User Story

As an operator, I would like to pull cloud init userData configuration from an external source (eg. Foreman) for using generic templating for userData.

Detailed Description

Have a field available in the Metal3MachineTemplate or in BareMetalHost under spec.userData like this :

apiVersion: metal3.io/v1alpha1
kind: BareMetalHost
metadata:
  name: test-host-baremetal-1
  namespace: cluster-alpha
spec:
  architecture: x86_64
  automatedCleaningMode: metadata
  bmc:
    address: idrac-virtualmedia://X.X.X.X/redfish/v1/Systems/System.Embedded.1
    credentialsName: creds-idrac
    disableCertificateVerification: true
  bootMode: legacy
  image:
    checksum: d5e1e43a3286e7dacc399b3fdb07ed0a0d4c9be965e2f6db3ecf7cecdeab1819
    checksumType: sha256
    format: qcow2
    url: http://Y.Y.Y.Y/CMS_AlmaLinux-9-GenericCloud-9.7.x86_64.qcow2
  online: true
  userData:
    url:  https://foreman.local/userdata/XX:XX:XX:XX:XX:XX/user-data

I know this is something feasible via Cloud Init using the cloud-config-url.

I am not really sure of how Metal3 could handle it, if it's into the scope or not.

Anything else you would like to add:

I am interested into this, so if it's something that's interests the community I could provide some effort into it.

/kind feature

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Details

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[dtantsur]

I don't have anything against it, but it requires some feature work on the Ironic side.

[s3rj1k]

I would extend this to support NetworkData also