diskimage-builder/diskimage_builder/elements/ubuntu-systemd-container/root.d/75-ubuntu-minimal-baseinstall

#!/bin/bash
# Copyright (c) 2014 Hewlett-Packard Development Company, L.P.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#    http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
# implied.
#
# See the License for the specific language governing permissions and
# limitations under the License.

if [ ${DIB_DEBUG_TRACE:-0} -gt 0 ]; then
    set -x
fi
set -eu
set -o pipefail

# We should manage this in a betterer way
sudo bash -c "cat << EOF >$TARGET_ROOT/etc/apt/sources.list
deb $DIB_DISTRIBUTION_MIRROR $DIB_RELEASE ${DIB_DEBIAN_COMPONENTS//,/ }
deb $DIB_DISTRIBUTION_MIRROR $DIB_RELEASE-updates ${DIB_DEBIAN_COMPONENTS//,/ }
deb $DIB_DISTRIBUTION_MIRROR $DIB_RELEASE-backports ${DIB_DEBIAN_COMPONENTS//,/ }
deb $DIB_DISTRIBUTION_MIRROR $DIB_RELEASE-security ${DIB_DEBIAN_COMPONENTS//,/ }
EOF"

sudo mount -t proc none $TARGET_ROOT/proc
sudo mount -o ro -t sysfs none $TARGET_ROOT/sys
trap "sudo umount $TARGET_ROOT/proc; sudo umount $TARGET_ROOT/sys" EXIT

apt_get="sudo chroot $TARGET_ROOT /usr/bin/apt-get" # dib-lint: safe_sudo

# Need to update to retrieve the signed Release file
$apt_get update

$apt_get clean
$apt_get dist-upgrade -y

to_install=""

# pre-bionic (18.04) brought this in via debootstrap, but init
# dependencies have narrowed in the container world, so now we add it
# explicitly here so it's brought in early.
if [ $DIB_RELEASE != "trusty" ] && [ $DIB_RELEASE != "xenial" ]; then
    to_install+="systemd-sysv "
fi

# default required
to_install+="sudo python3 " # dib-lint: safe_sudo

$apt_get install -y $to_install