---
upgrade:
  - |
    Consistent network device naming is now enabled by default in overcloud
    root disk images, by setting ``net.ifnames=1`` on the kernel command line.
    This is performed using the ``DIB_BOOTLOADER_DEFAULT_CMDLINE``
    diskimage-builder environment variable, which is set to ``nofb nomodeset
    gfxpayload=text net.ifnames=1`` to preserve diskimage-builder defaults. To
    restore existing behaviour, set ``DIB_BOOTLOADER_DEFAULT_CMDLINE`` to
    ``nofb nomodeset gfxpayload=text net.ifnames=0`` in the
    ``kolla_bifrost_dib_env_vars_extra`` dictionary.