Dockerfile to generate systemd (/sbin/init) capable image for ansible molecule (Debian, Ubuntu, RHEL, CentOS, Fedora, OpenSUSE)

Dockerfile.j2.md

{% if item.registry is defined %}
FROM {{ item.registry.url }}/{{ item.image }}
{% else %}
FROM {{ item.image }}
{% endif %}

{% if item.env is defined %}
{% for var, value in item.env.items() %}
{% if value %}
ENV {{ var }} {{ value }}
{% endif %}
{% endfor %}
{% endif %}

# ###
# For usage with ansible molecule
# Use the following in the molecule.yml
# Tested with:
# - ubuntu:focal, ubuntu:bionic, ubuntu:xenial
# - debian:buster, debian:stretch, debian:jessie
# - centos:8, centos:7, centos:6
# - fedora:32, fedora:31, fedora:30
# - opensuse/leap:15.2, opensuse/leap:15.1, opensuse/leap:15.0
# - alpine:3.12, alpine:3.11, alpine:3.10
# ###
# driver:
#   name: docker
# platforms:
#   - name: molecule-ubuntu-focal
#     image: ubuntu:focal
#     dockerfile: Dockerfile.j2
#     override_command: false
#     privileged: true
#
#   - name: molecule-debian-buster
#     image: debian:buster
#     env:
#       APT_KEY_DONT_WARN_ON_DANGEROUS_USAGE: "1"
#     dockerfile: Dockerfile.j2
#     override_command: false
#     privileged: true
#
#   - name: molecule-centos-7
#     image: centos:7
#     dockerfile: Dockerfile.j2
#     override_command: false
#     privileged: true
# ###

MAINTAINER Mathijs van Veluw - TechNative B.V. <mathijs -AT- technative.nl>

ENV container docker
ENV LC_ALL=C TZ=UTC TERM=xterm-256color

RUN if [ $(command -v apt-get) ]; then \
      export DEBIAN_FRONTEND=noninteractive ; \
      export APT_KEY_DONT_WARN_ON_DANGEROUS_USAGE=1 ; \
      apt-get update \
      && apt-get install -y dbus systemd gnupg systemd-sysv python3 sudo bash ca-certificates iproute2 python3-apt aptitude \
      && apt-get clean \
      && rm -rf /usr/share/doc/* /usr/share/man/* /var/lib/apt/lists/* /tmp/* /var/tmp/*; \
    elif [ $(command -v dnf) ]; then \
      dnf makecache \
      && dnf --assumeyes install /usr/bin/python3 /usr/bin/python3-config /usr/bin/dnf-3 findutils dbus systemd sudo bash iproute \
      && dnf clean all \
      && rm -rf /usr/share/doc/* /usr/share/man/* /tmp/* /var/tmp/*; \
    elif [ $(command -v yum) ]; then \
      yum makecache fast \
      && yum install -y /usr/bin/python /usr/bin/python2-config dbus systemd sudo yum-plugin-ovl bash iproute \
      && sed -i 's/plugins=0/plugins=1/g' /etc/yum.conf \
      && yum clean all \
      && rm -rf /usr/share/doc/* /usr/share/man/* /tmp/* /var/tmp/*; \
    elif [ $(command -v zypper) ]; then \
      zypper refresh \
      && zypper install -y python3 dbus-1 systemd systemd-sysvinit sudo bash iproute2 \
      && zypper clean -a \
      && rm -rf /usr/share/doc/* /usr/share/man/* /tmp/* /var/tmp/*; \
    elif [ $(command -v apk) ]; then \
      apk update \
      && apk add --no-cache python3 dbus sudo bash ca-certificates \
      && rm -rf /usr/share/doc/* /usr/share/man/* /tmp/* /var/tmp/*; \
    fi

# Don't start any optional services except for the few we need.
# Ignore any errors since some directories could not exists on some distributions
RUN find /etc/systemd/system \
      /lib/systemd/system \
      /usr/lib/systemd/system \
      -path '*.wants/*' \
      -not -name '*dbus*' \
      -not -name '*journald*' \
      -not -name '*systemd-tmpfiles*' \
      -not -name '*systemd-user-sessions*' \
      -exec rm \{} \; ; >/dev/null 2>&1

# If image does have systemd set the default to be multi-user else leave it as is.
RUN if [ $(command -v systemctl) ]; then \
      systemctl set-default multi-user.target; \
    fi

STOPSIGNAL SIGRTMIN+3

CMD ["/sbin/init"]