Perfroms a chroot backup ensuring enough space is available.

chrootbu

#!/bin/sh

ANSWER=''
APPLICATION="${0##*/}"
AVAIL=''
AVAILGB=''
BACKTAG=''
BACKUP=''
CHROOT=''
CHROOTS=''
CHROOTSIZE=''
CHROOTSIZEGB=''
DATE="$(date '+%Y%m%d-%H%M')"
DESTDIR=''
MOUNTPT=''
SIZE=''
SIZEGB=''
USED=''
USEDGB=''

echo_e='/bin/echo -e'

###
### If we're not running as root, restart as root.
if [ ${UID:-$(id -u)} -ne 0 ]; then
  ${echo_e} "...elevating ${USER} to superuser..."
  exec sudo /bin/sh -e "$0" "$@"
fi

###
### Set critical vars
CHROOT="${1:-list}"
DESTDIR="${2:-$(pwd)}"
BACKTAG="${3}"
if [ -n "$BACKTAG" ]; then BACKTAG="_${BACKTAG}"; fi
MOUNTPT="$(dirname ${DESTDIR})"

###
### Find CHROOTS
if [ -d /var/crouton/chroots ]
then CHROOTS="/var/crouton/chroots"
else CHROOTS="/usr/local/chroots"
fi

###
### Check for args
if [ -z "${1}" ];then
  ${echo_e} "USAGE: ${APPLICATION} [chroot_name | list] [backup_location] [backup_tag]\n"
elif [ "${1}" = '-h' ];then
  ${echo_e} "USAGE: ${APPLICATION} [chroot_name | list] [backup_location] [backup_tag]\n"
  exit
fi

###
### Get mountpoint
while :
do
  if grep -q " ${MOUNTPT} " /proc/mounts;
  then break
  else MOUNTPT="$(dirname ${MOUNTPT})"; continue
  fi
done

###
### Set more vars
${echo_e} -n "Gathering size requirements, etc. ..."
DATE=$(date '+%Y%m%d-%H%M')
BACKUP="${CHROOT}-${DATE}${BACKTAG}.tar.gz"
CHROOTSIZE="$(sudo du --max-depth=0 ${CHROOTS}/${CHROOT} 2>/dev/null | awk '{print $1}')"
CHROOTSIZEGB="$(sudo du -h --max-depth=0 ${CHROOTS}/${CHROOT} 2>/dev/null | awk '{print $1}')"
SIZE=$(df  ${MOUNTPT} 2>/dev/null | grep -v ^File | awk '{print $2}')
USED=$(df  ${MOUNTPT} 2>/dev/null | grep -v ^File | awk '{print $3}')
AVAIL=$(df ${MOUNTPT} 2>/dev/null | grep -v ^File | awk '{print $4}')
SIZEGB=$(df  -h ${MOUNTPT} 2>/dev/null | grep -v ^File|awk '{print $2}')
USEDGB=$(df  -h ${MOUNTPT} 2>/dev/null | grep -v ^File|awk '{print $3}')
AVAILGB=$(df -h ${MOUNTPT} 2>/dev/null | grep -v ^File|awk '{print $4}')
${echo_e}

###
### Check for valid chroot(s)
if ! [ -d ${CHROOTS}/${CHROOT} ]; then
  if [ "${CHROOT}" = "list" ]; then
#   ${echo_e} "Your chroots: $(ls -m "$CHROOTS")\n"
    ${echo_e} "\nValid CHROOT(S) and uncompressed size(s) are:\n"
    for each in `ls -1 $CHROOTS`; do
      CTR=$(($CTR + 1))
      CHROOTSIZEGB="$(sudo du -h --max-depth=0 ${CHROOTS}/${each} 2>/dev/null | awk '{print $1}')"
      ${echo_e} "	$CTR) $each:	$CHROOTSIZEGB"
      CRSIZE="$(echo $CHROOTSIZEGB|sed 's/G$//')"
      STOTAL="$(echo $STOTAL + $CRSIZE)"
    done
    TOTAL="$(echo "$STOTAL" | sed 's/^+ //' | bc)"
    echo 
    ${echo_e} "	TOTAL CHROOTS:	${TOTAL}G"
    echo 
    exit 0
  fi
  ${echo_e} "\nSorry no CHROOT named '${CHROOT}' was found in ${CHROOTS} - aborting...\n"
  ${echo_e} "Valid CHROOT(S) are: $(ls -m ${CHROOTS})\n"
  exit 1
fi

###
### Show destination size
${echo_e} "\n${APPLICATION}: Back up of crouton chroot: '${CHROOT}'\n"
${echo_e} "Your disk size in '${DESTDIR}' is below:\n"
df -h ${MOUNTPT}
${echo_e} "\nThe size of '${CHROOT}' is: ${CHROOTSIZEGB} (uncompressed)\n"

###
### Notify of space available
if ! [ "${AVAIL}" -gt "${CHROOTSIZE}" ]; then
  ${echo_e} "\nYou don't have enough free space left in '${DESTDIR}' to backup your chroot, boo!\n"
  ${echo_e} "\nFree-up more space or save your backup to external media.\n"
  exit 1
else
  ${echo_e} "You have sufficient free space for a backup, yay!\n"
fi

###
### Request backup operation
${echo_e} "Backup filename will be: ${DESTDIR}/${BACKUP}\n"
echo -n "Perform  backup of '${CHROOTS}/${CHROOT}' (Y/n/q) ? " 1>&2
read ANSWER; if [ -z "${ANSWER}" ]; then ANSWER='y'; fi
case "${ANSWER}" in
  [yY]*) echo ;;
  *) ${echo_e} "\nQuitting...\n"; exit 0;;
esac

###
### Perform backup
tar cf - ${CHROOTS}/${CHROOT}/ -P 2>/dev/null |\
  pv -i 5 -w 80 -berps $(du -sb ${CHROOTS}/${CHROOT} |\
  awk '{print $1}') |\
  gzip > ${DESTDIR}/${BACKUP}

###
### Show compressed backup file
chown ${SUDO_USER}:${SUDO_USER} ${DESTDIR}/${BACKUP}
${echo_e} "\nBackup of '${CHROOTS}/${CHROOT}' done.\n"
${echo_e} "The file is stored in '${DESTDIR}\n"
ls -hlF "${DESTDIR}/${BACKUP}"

echo

Cleaned up and fixed mount point and destination directory.