mkimage-yum-chroot.sh

#!/usr/bin/env bash
#
# Create a base image work folder.
#
# Does it all. Pulls install repos from archive,
# updates to latest packages,
# cleans up temp apt files to reduce image size,
# 
# image file is not created
#
# chroot can be used to edit work folder

clear
set +x

echo "Centos or Oracle Linux  7.x base image work folder"
echo
echo "edit bin_folder variable for where you placed the list files"
echo "add-packages.txt, remove-packages.txt"
echo
echo "------------------------------------------------------------"
echo "Default is to work with Centos repo. Edit WHICH REPO section to"
echo "use Oracle Linux repo"
echo
echo "Enable epel repo section to install packages from epel repo"
echo ""
echo "To see possible group names run: sudo yum group list"
echo "------------------------------------------------------------"
echo 
echo 

usage() {
    cat <<EOOPTS
$(basename $0) [OPTIONS] <work_folder>
OPTIONS:
  -e "<env group>"    Environment Group to install in the container.
                      The default is "Minimal Install". ONLY USE ONCE.
  -g "<groups>"       The groups of packages to install in the container.
                      The default is blank. May Use mutiple times.
  -y <yumconf>        The path to the yum config to install packages from. The
                      default is /etc/yum.conf for Centos/RHEL
                      and /etc/dnf/dnf.conf for Fedora
EOOPTS
    exit 1
}

# option defaults
yum_config=/etc/yum.conf
if [ -f /etc/dnf/dnf.conf ] && command -v dnf &> /dev/null; then
	yum_config=/etc/dnf/dnf.conf
	alias yum=dnf
fi

#set bin folder
bin_folder=/home/kenny/mkimage

# for names with spaces, use double quotes (") as install_env_group=('Core' '"Compute Node"')
install_env_group=()
install_packages=()
install_other_groups=()
remove_packages=()
while getopts ":y:g:h:e:" opt; do
    case $opt in
        y)
            yum_config=$OPTARG
            ;;
        h)
            usage
            ;;
	e)
            install_env_group="$OPTARG"
            ;;			
        g)
            install_other_groups+=("$OPTARG")
            ;;
        \?)
            echo "Invalid option: -$OPTARG"
            usage
            ;;
    esac
done
shift $((OPTIND - 1))
work_folder=$1

if [[ -z $work_folder ]]; then
    usage
fi

# default to Core group if not specified otherwise
if [ ${#install_env_group[*]} -eq 0 ]; then
   install_env_group=('Minimal Install')
fi

target=$(mktemp -d --tmpdir $(basename $0).XXXXXX)

set -x

mkdir -m 755 "$target"/dev
mknod -m 600 "$target"/dev/console c 5 1
mknod -m 600 "$target"/dev/initctl p
mknod -m 666 "$target"/dev/full c 1 7
mknod -m 666 "$target"/dev/null c 1 3
mknod -m 666 "$target"/dev/ptmx c 5 2
mknod -m 666 "$target"/dev/random c 1 8
mknod -m 666 "$target"/dev/tty c 5 0
mknod -m 666 "$target"/dev/tty0 c 4 0
mknod -m 666 "$target"/dev/urandom c 1 9
mknod -m 666 "$target"/dev/zero c 1 5

# amazon linux yum will fail without vars set
if [ -d /etc/yum/vars ]; then
	mkdir -p -m 755 "$target"/etc/yum
	cp -a /etc/yum/vars "$target"/etc/yum/
fi

# install environment group
if [[ -n "$install_env_group" ]];
then
    yum -c "$yum_config" --installroot="$target" --releasever=/ --setopt=tsflags=nodocs \
        --setopt=group_package_types=mandatory -y groupinstall "${install_env_group[*]}"
fi

#Which repo - choose only one below
#For Centos use:
cp /etc/yum.repos.d/CentOS-Base.repo "$target"/etc/yum.repos.d/
#For Oracle Linux use:
#cp /etc/yum.repos.d/public-yum-ol7.repo "$target"/etc/yum.repos.d/

#Enable epel repo
#cp /etc/yum.repos.d/epel.repo "$target"/etc/yum.repos.d/

#Create docker-image-info file
info_file="$target"/etc/docker-image-info
echo "Date/Time Created" >> $info_file
echo "-----------------------------" >> $info_file
date >> $info_file
echo >> $info_file
echo "Environment Group Installed" >> $info_file
echo "-----------------------------" >> $info_file
echo $install_env_group >> $info_file
echo >> $info_file
echo "Packages Removed" >> $info_file
echo "-----------------------------" >> $info_file

# remove packages
rm -f "$target"/etc/yum/protected.d/systemd.conf
#note that the above file should also be removed on the host running this script

in_folder=/home/kenny/mkimage
package_removal_list=$bin_folder/remove-packages.txt
while read package_removal;
    do
      yum -c "$yum_config" --installroot="$target" --releasever=/ --setopt=tsflags=nodocs \
          --setopt=group_package_types=mandatory -y remove "$package_removal"
      echo $package_removal >> $info_file
    done < $package_removal_list

# install other groups
echo "" >> $info_file
echo "Other Groups Installed" >> $info_file
echo "-----------------------------" >> $info_file

if [[ -n "$install_other_groups" ]];
then
    for group_name in "${install_other_groups[@]}"; do
      yum -c "$yum_config" --installroot="$target" --releasever=/ --setopt=tsflags=nodocs \
          --setopt=group_package_types=mandatory -y groupinstall "$group_name"
      echo $group_name >> $info_file
    done
fi

# install additional packages
echo "" >> $info_file
echo "Additional Packages Installed" >> $info_file
echo "-----------------------------" >> $info_file

package_addition_list=$bin_folder/add-packages.txt
while read package_name;
     do
      yum -c "$yum_config" --installroot="$target" --releasever=/ --setopt=tsflags=nodocs \
          --setopt=group_package_types=mandatory -y install "$package_name"
      echo $package_name >> $info_file
    done < $package_addition_list

yum -c "$yum_config" --installroot="$target" -y clean all

cat > "$target"/etc/sysconfig/network <<EOF
NETWORKING=yes
HOSTNAME=localhost.localdomain
EOF

# effectively: febootstrap-minimize --keep-zoneinfo --keep-rpmdb --keep-services "$target".
#  locales
rm -rf "$target"/usr/{{lib,share}/locale,{lib,lib64}/gconv,bin/localedef,sbin/build-locale-archive}
#  docs and man pages
rm -rf "$target"/usr/share/{man,doc,info,gnome/help}
#  cracklib
rm -rf "$target"/usr/share/cracklib
#  i18n
rm -rf "$target"/usr/share/i18n
#  yum cache
rm -rf "$target"/var/cache/yum
mkdir -p --mode=0755 "$target"/var/cache/yum
#  sln
rm -rf "$target"/sbin/sln
#  ldconfig
rm -rf "$target"/etc/ld.so.cache "$target"/var/cache/ldconfig
mkdir -p --mode=0755 "$target"/var/cache/ldconfig

if [ -z "$version" ]; then
    for file in "$target"/etc/{redhat,system}-release
    do
        if [ -r "$file" ]; then
            version="$(sed 's/^[^0-9\]*\([0-9.]\+\).*$/\1/' "$file")"
            break
        fi
    done
fi

#copy clean-image.sh
cp $bin_folder/clean-pre-image.sh $target/root/
chroot $target /bin/bash -c "chmod 755 /root/clean-pre-image.sh"

#move tmp folder to work folder
mv $target $work_folder


#preview with chroot
set +x
clear
echo "WORK FOLDER IMAGE INFO"
echo "---------------------------------------------------------------------"
echo
chroot $work_folder /bin/bash -c "cat /etc/docker-image-info"


#closing comments
echo
echo
echo "CLOSING HELP"
echo "---------------------------------------------------------------------"
echo
echo "use chroot to further test and edit contents of your work folder:"
echo
echo "sudo chroot $work_folder /bin/bash"
echo
echo "when ready create your docker image manually by running:"
echo
echo "sudo tar -C $work_folder -c . | docker import - <name>:<tag>"
echo
echo "To minimize the size of the image file after using yum"
echo "and prior to running the above tar/import command"
echo "run:"
echo
echo "sudo yum clean all"
echo
echo
echo

#I can only imagine