build centos6 base image for docker

build-centos.sh

#!/bin/bash

set -e

## requires running as root because filesystem package won't install otherwise,
## giving a cryptic error about /proc, cpio, and utime.  As a result, /tmp
## doesn't exist.
[ $( id -u ) -eq 0 ] || { echo "must be root"; exit 1; }

tmpdir=$( mktemp -d )
trap "echo removing ${tmpdir}; rm -rf ${tmpdir}" EXIT

febootstrap \
    -u http://mirrors.sohu.com/centos/6/updates/x86_64/ \
    -i bash \
    -i centos-release \
    -i yum \
    -i iputils \
    -i tar \
    -i which \
    -i wget \
    -i vim-minimal \
    -i http://dl.fedoraproject.org/pub/epel/6/x86_64/epel-release-6-8.noarch.rpm \
    centos6-min \
    ${tmpdir} \
    http://mirrors.sohu.com/centos/6/os/x86_64/

echo "Minimal image size"
febootstrap-minimize --keep-locale --keep-zoneinfo --keep-rpmdb --keep-services --keep-ldconfig "$tmpdir"

febootstrap-run ${tmpdir} -- sh -c 'echo "NETWORKING=yes" > /etc/sysconfig/network'
febootstrap-run ${tmpdir} -- sh -c 'echo "NETWORKING_IPV6=no" >> /etc/sysconfig/network'

## remove unused locales
## https://github.com/jayjanssen/packer-percona/blob/master/provisioners/remove-extra-locales.sh
echo "remove unused locales"
febootstrap-run ${tmpdir} -- bash -c 'find /usr/share/locale -maxdepth 1 -mindepth 1 -type d | grep -v -e "en_US" | xargs rm -rf'
febootstrap-run ${tmpdir} -- bash -c 'localedef --list-archive | grep -v -e "en_US" | xargs localedef --delete-from-archive'
febootstrap-run ${tmpdir} -- mv /usr/lib/locale/locale-archive /usr/lib/locale/locale-archive.tmpl
febootstrap-run ${tmpdir} -- build-locale-archive

echo "remove ldconfig cache"
febootstrap-run ${tmpdir} -- bash -c 'rm -rf /etc/ld.so.cache'
febootstrap-run ${tmpdir} -- bash -c 'rm -rf /var/cache/ldconfig/*'

## set timezone of container to UTC
echo "set timezone"
#febootstrap-run ${tmpdir} -- ln -f /usr/share/zoneinfo/Etc/UTC /etc/localtime
febootstrap-run ${tmpdir} -- ln -f /usr/share/zoneinfo/Asia/Shanghai /etc/localtime

## xz gives the smallest size by far, compared to bzip2 and gzip, by like 50%!
echo "compress image"
febootstrap-run ${tmpdir} -- tar -cf - . | xz > centos6-min.tar.xz

echo "build image"
tag=${1:-latest}
cat centos6-min.tar.xz | docker import - centos6-base-min:${tag}
rm centos6-min.tar.xz

echo "done"