docker-systemd-prepare

#!/usr/bin/env bash
set -e
DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" >/dev/null 2>&1 && pwd )"
PATH="$DIR:$PATH"

#
# docker-systemd-prepare
#
# This script prepares the operating system to run a full systemd setup inside a docker container.
#
# It was appropriated from Jeff Geerling's Dockerfiles:
#
#  Ubuntu

#  - https://github.com/geerlingguy/docker-ubuntu2004-ansible/blob/master/Dockerfile
#  - https://github.com/geerlingguy/docker-ubuntu1804-ansible/blob/master/Dockerfile
#  - https://github.com/geerlingguy/docker-ubuntu1604-ansible/blob/master/Dockerfile
#
#  CentOS
#  - https://github.com/geerlingguy/docker-centos7-ansible/blob/master/Dockerfile
#  - https://github.com/geerlingguy/docker-centos8-ansible/blob/master/Dockerfile
#
#  Each OS needs slightly different preparation. This script contains logic to work on any of the listed OS.
#

set -e

command_exists() {
	command -v "$@" > /dev/null 2>&1
}

get_distribution() {
	lsb_dist=""
	# Every system that we officially support has /etc/os-release
	if [ -r /etc/os-release ]; then
		lsb_dist="$(. /etc/os-release && echo "$ID")"
	fi
	# Returning an empty string here should be alright since the
	# case statements don't act unless you provide an actual value
	echo "$lsb_dist"
}

prepare_ubuntu1804() {
  apt-get update \
    && apt-get install -y --no-install-recommends \
       apt-utils \
       locales \
       rsyslog \
       systemd \
       systemd-cron \
       sudo \
       iproute2 \
       curl \
       ca-certificates \
    && rm -Rf /var/lib/apt/lists/* \
    && rm -Rf /usr/share/doc && rm -Rf /usr/share/man \
    && apt-get clean

  sed -i 's/^\($ModLoad imklog\)/#\1/' /etc/rsyslog.conf
  locale-gen en_US.UTF-8

  # Install the initctl faker script from @geerlingguy
  initctl_faker_url="https://raw.githubusercontent.com/geerlingguy/docker-ubuntu1804-ansible/d75f3d7/initctl_faker"
  initctl_faker_path="/sbin/initctl"

  curl -ksSL $initctl_faker_url -o $initctl_faker_path
  chmod +x $initctl_faker_path

  # Remove unnecessary getty and udev targets that result in high CPU usage when using
  # multiple containers with Molecule (https://github.com/ansible/molecule/issues/1104)
  rm -f /lib/systemd/system/systemd*udev* \
    && rm -f /lib/systemd/system/getty.target

  # Allow mysql to be installed?
  # Error: https://github.com/opendevshop/devshop/pull/586/checks?check_run_id=675721197#step:4:484
  # Proposed solution: https://stackoverflow.com/questions/24988947/install-mysql-in-docker-and-expose-mysql-service-to-outside
  echo exit 0 > /usr/sbin/policy-rc.d
}

prepare_centos7() {
  # Install systemd -- See https://hub.docker.com/_/centos/
  yum -y update; yum clean all; \
    (cd /lib/systemd/system/sysinit.target.wants/; for i in *; do [ $i == systemd-tmpfiles-setup.service ] || rm -f $i; done); \
    rm -f /lib/systemd/system/multi-user.target.wants/*;\
    rm -f /etc/systemd/system/*.wants/*;\
    rm -f /lib/systemd/system/local-fs.target.wants/*; \
    rm -f /lib/systemd/system/sockets.target.wants/*udev*; \
    rm -f /lib/systemd/system/sockets.target.wants/*initctl*; \
    rm -f /lib/systemd/system/basic.target.wants/*;\
    rm -f /lib/systemd/system/anaconda.target.wants/*;

# Install requirements.
  yum makecache fast \
    && yum -y install deltarpm epel-release initscripts \
    && yum -y update \
    && yum -y install \
      sudo \
      which \
      python-pip \
    && yum clean all

  # Disable requiretty.
  sed -i -e 's/^\(Defaults\s*requiretty\)/#--- \1/'  /etc/sudoers

}

prepareAll() {
  mkdir -p /etc/ansible
}

# perform some very rudimentary platform detection
lsb_dist=$( get_distribution )
lsb_dist="$(echo "$lsb_dist" | tr '[:upper:]' '[:lower:]')"

case "$lsb_dist" in

  ubuntu)
    if command_exists lsb_release; then
      dist_version="$(lsb_release --release | cut -f2)"
      case "$dist_version" in
        "14.04")
          dist_version_name="trusty"
        ;;
        "16.04")
          dist_version_name="xenial"
        ;;
        "18.04")
          dist_version_name="bionic"
        ;;
        "20.04")
          dist_version_name="focal"
        ;;
      esac
    fi
    if [ -z "$dist_version" ] && [ -r /etc/lsb-release ]; then
      dist_version="$(. /etc/lsb-release && echo "$DISTRIB_RELEASE")"
      dist_version_name="$(. /etc/lsb-release && echo "$DISTRIB_CODENAME")"
    fi
  ;;

  debian|raspbian)
    dist_version="$(sed 's/\/.*//' /etc/debian_version | sed 's/\..*//')"
    case "$dist_version" in
      10)
        dist_version_name="buster"
      ;;
      9)
        dist_version_name="stretch"
      ;;
      8)
        dist_version_name="jessie"
      ;;
    esac
  ;;

  centos)
    if [ -z "$dist_version" ] && [ -r /etc/os-release ]; then
      dist_version="$(. /etc/os-release && echo "$VERSION_ID")"
    fi
  ;;

  rhel|ol|sles)
    ee_notice "$lsb_dist"
    exit 1
    ;;

  *)
    if command_exists lsb_release; then
      dist_version="$(lsb_release --release | cut -f2)"
    fi
    if [ -z "$dist_version" ] && [ -r /etc/os-release ]; then
      dist_version="$(. /etc/os-release && echo "$VERSION_ID")"
    fi
  ;;

esac

echo "OS Detected: $lsb_dist $dist_version ($dist_version_name)"

# Break out preparation into separate functions.
case "$lsb_dist $dist_version" in
  "ubuntu 18.04")
    prepare_ubuntu1804
  ;;
  "centos 7")
    prepare_centos7
  ;;
esac

# Run OS-agnostic preparation scripts.
prepareAll