Fedora atomic DIB element can't be used with dracut-regenerate element

The dracut-regenerate element can be used to rebuild the ramdisk of an image which uses dracut (CentOS, RHEL, Fedora, etc.). This can be useful if additional drivers are required in the ramdisk to support a particular set of hardware (RAID controllers, NICs, etc.).

Magnum's fedora-atomic DIB element[1] can't be used with dracut-regenerate element as it removes the dracut package at the end of it's finalise.d/80-fedora-atomic script. Since the dracut-regenerate requires dracut to be installed in its finalise.d/98-dracut-regenerate script[2], the dracut-regenerate element fails to build. The same is true for the now removed dracut-network element (available in diskimage-builder < 2.6.0).

With a workaround for this issue in place, it is still necessary to set the following environment variables to inform dracut of the unusual location of the kernel and ramdisk:

export DIB_BAREMETAL_KERNEL_PATTERN='ostree/fedora-atomic-*/vmlinuz*'
export DIB_BAREMETAL_INITRD_PATTERN='ostree/fedora-atomic-*/initramfs-*'

[1] https://github.com/openstack/magnum/tree/907415c984e95e09a8b872f3c551ae6108c91de1/magnum/drivers/common/image/fedora-atomic
[2] https://github.com/openstack/diskimage-builder/blob/master/diskimage_builder/elements/dracut-regenerate/finalise.d/98-dracut-regenerate