Iso in machine-os-images references RHCOS in 4.12 instead of FCOS

[bernhardloos]

This leads to ironic trying to provision a host with RHCOS first.
This was correct in 4.11.

From 4.11.0-0.okd-2023-01-14-152430:

docker run --rm quay.io/openshift/okd-content@sha256:2ee50ca9e09fd8865c6b322e5e096a246d819bad0a264a557c4c128d5a95a387 cat coreos/coreos-stream.json | head -n 15
{
    "stream": "stable",
    "metadata": {
        "last-modified": "2022-07-26T22:48:18Z",
        "generator": "fedora-coreos-stream-generator v0.2.7"
    },
    "architectures": {
        "aarch64": {
            "artifacts": {
                "aws": {
                    "release": "36.20220716.3.1",
                    "formats": {
                        "vmdk.xz": {
                            "disk": {
                                "location": "https://builds.coreos.fedoraproject.org/prod/streams/stable/builds/36.20220716.3.1/aarch64/fedora-coreos-36.20220716.3.1-aws.aarch64.vmdk.xz",

From 4.12.0-0.okd-2023-02-04-212953:

docker run --rm quay.io/openshift/okd-content@sha256:4640208b8d3ac8ff0441972588163e29de61b6154734f0cb3ec5f906da57ceff cat coreos/coreos-stream.json | head -n 15
{
  "stream": "rhcos-4.11",
  "metadata": {
    "last-modified": "2022-08-10T14:54:27Z",
    "generator": "plume cosa2stream 0.13.0+9-ga19a99c94"
  },
  "architectures": {
    "aarch64": {
      "artifacts": {
        "aws": {
          "release": "412.86.202208101040-0",
          "formats": {
            "vmdk.gz": {
              "disk": {
                "location": "https://rhcos.mirror.openshift.com/art/storage/releases/rhcos-4.12-aarch64/412.86.202208101040-0/aarch64/rhcos-412.86.202208101040-0-aws.aarch64.vmdk.gz",

[bernhardloos]

With 4.12.0-0.okd-2023-03-05-022504, the image now contains FCOS, but it's version 37.20221127.3.0 instead of 37.20230205.3.0 which is actually used by the cluster. It's not that critical, because the upgrade works in this case, but it would still be nice if the correct image would be installed immediately to safe some time and download bandwidth.

[LorbusChris]

@bernhardloos technically, that is expected right now, as that's the FCOS version that the installer references for bootimages: https://github.com/openshift/installer/blob/44b1b0bf0377270adcbabb34062a76fedb9028ad/data/data/coreos/fcos.json#L37

OKD/FCOS does not currently produce its own bootimages -- vanilla FCOS is always booted first and then rebased.
We need coreos/fedora-coreos-tracker#1151 to enable booting into OKD/FCOS right away.