diskimage-builder/elements/redhat-common/pre-install.d/15-remove-grub

#!/bin/bash
if [ "${DIB_DEBUG_TRACE:-0}" -gt 0 ]; then
    set -x
fi
set -eu
set -o pipefail

# grub2 isn't available on rhel6/centos6; they are setup to use
# extlinux.  skip this
# you would think we could match on $DISTRO or something else; but
# we can't because the rhel/centos elements are a bit mixed up;
# centos-minimal for example sets distro to "centos".  so the best
# check is just for the original "grub-install" script
if [ -f /sbin/grub-install ]; then
    exit 0
fi

# remove grub2 package.  As described in
# elements/ubuntu/pre-install.d/00-remove-grub; the grub post-kernel
# install hook will barf if the block device can't be found (as
# happens in a chroot).
#
# XXX : it is not clear this is necessary for fedora/centos7 and it's
# install hooks.  Investigation is required.
if rpm -q grub2; then
    install-packages -e grub2
fi

# now configure things to re-install grub at the end.  We don't want
# to rely on vm/finalise.d/51-bootloader to simply reinstall the
# package via the package-manager, because at that point (during
# finalise) the build-time yum-cache has been unmounted (hence the
# local-cache looks empty) and yum may try to repopulate the
# local-cache with all the grub2 dependencies.  This is slow, and
# potentially fills up the disk.
#
# XXX : At this point, keepcache=0 *should* probably be set for
# yum/dnf.  We have not standarised/documented that this will be done,
# however.  This would *probably* stop dependencies being populated
# into the cache.  We could investigate this, and possibly remove this
# all together if we standardise some of these behaviours.

# So we download the latest grub2 package and setup the install script
# to just install the single-package, which will be called later by
# vm/finalise.d/51-bootloader
install-packages -d /tmp/grub grub2
echo "rpm -i /tmp/grub/*.rpm" > /tmp/grub/install