coreos-boot-disk link not working with multipath on early boot

[tlbueno]

On a scenario where a device mapper is used (ie: multipath), coreos-boot-disk is linked with the "physical" disk(ie: sda). Because of this the installation fails when try to changing partitions as coreos-boot-disk should be linked to the device mapper (ie: dm-0) to be allowed to partition the disk.

There is also a issue on ignition side that impacts the changes on partitions and also needs to be included to get this issue fixed

• 2128
• PR

To reproduce the issue run the command below

cosa run --qemu-size +35G --qemu-multipath --kargs 'rd.multipath=default rd.debug rw' --debug --devshell-console --butane tmp/butane.yaml

butane file contents:

variant: fcos
version: 1.6.0
kernel_arguments:
  should_exist:
    - rd.debug
    - rd.udev.log_level=debug
    - udev.log_level=debug
    - rd.systemd.log_level=debug
    - systemd.log_level=debug
storage:
  disks:
  - device: /dev/disk/by-id/coreos-boot-disk
    wipe_table: false
    partitions:
    - number: 4
      label: root
      size_mib: 20480
      resize: true
    - number: 5
      label: var
      size_mib: 0
  filesystems:
    - path: /var
      device: /dev/disk/by-partlabel/var
      format: ext4
      with_mount_unit: true
      wipe_filesystem: true
      label: var