vmbackuprotate

#!/bin/bash

#####################################
## Rotate virtual machines backups ##
#####################################

usage ()
{
  echo ''
  echo 'Usage : vmbackuprotate <config file path>'
  echo '    config file path: path to configuration file'
  echo ''
}

# If wrong number of arguments, print usage and exit
[ $# -ne 1 ] && { usage; exit 1; }


# Parameters
# ----------

# Default values

# Day of the week for weekly backup (1 is monday, 7 is sunday)
WEEKLY_DAY_OF_WEEK=7

# Keep daily backups for N days
DAILY_BACKUPS_LIFETIME=7

# Keep weekly backups for N weeks
WEEKLY_BACKUPS_LIFETIME=4

# Names of VM to backup
# (if not found in config file, no VM to backup)
VM_NAMES=""

# Remote directories to synchronize
# (if not found in config file, no remote dir to synchronize)
REMOTE_DIRS=""


# Source config file (overrides defaults)
source $1


## Check directories are defined (no default values for those)
if [[ -z $VM_DIR ]]; then { echo >&2 "Missing parameter VM_DIR in config file"; exit 3; }; fi
if [[ -z $BAK_DIR ]]; then { echo >&2 "Missing parameter BAK_DIR in config file"; exit 3; }; fi


# Script
# ------

# Create backup dirs if they don't exist

DAILY_DIR=$BAK_DIR/daily
WEEKLY_DIR=$BAK_DIR/weekly

mkdir -p $DAILY_DIR && mkdir -p $WEEKLY_DIR || { echo >&2 "Error creating backup directories. Aborting."; exit 4; }

# Make backups

for vm in $VM_NAMES

do

    echo "Backup $vm..."

    # Backup VM
    BAK_FILENAME="$vm"_`date +%y%m%d`.qcow2
    BAK_FILEPATH=$BAK_DIR/$BAK_FILENAME
    vmbackup $VM_DIR $vm $BAK_FILEPATH || { echo >&2 "Backup failed for $vm "; continue; }

    # Move backup to daily directory
    mv $BAK_FILEPATH $DAILY_DIR

    # If today is weekly backup, hard link to "weekly" directory
    if [ `date +%u` -eq $WEEKLY_DAY_OF_WEEK ]
    then
        ln $DAILY_DIR/$BAK_FILENAME $WEEKLY_DIR
    fi

done

# Get rid of old backups
# LIFETIME = 0 means "do not delete backups, keep them permanently"
# The script does not run every week at the exact same time of day, so we
# subtract 6 hours to deal with this approximation
if [ $DAILY_BACKUPS_LIFETIME -gt 0 ]; then
    find $DAILY_DIR -mmin +$(( ($DAILY_BACKUPS_LIFETIME * 24 - 6 ) * 60 )) -delete
fi

if [ $WEEKLY_BACKUPS_LIFETIME -gt 0 ]; then
    find $WEEKLY_DIR -mmin +$(( ($WEEKLY_BACKUPS_LIFETIME * 7 * 24 - 6 ) * 60 )) -delete
fi

# Synchronize remote directories

for remote in $REMOTE_DIRS

do

    echo "Synchronize $remote..."

    # A 'vmbackup' directory is created in each remote dir
    # Hardcoding a subdirectory name is not elegant, but it is a simple measure to avoid wreaking havoc
    # in the system if entering / as remote dir by mistake in the config file.
    ionice -c2 -n7 nice -n19 rsync -a -H --delete --progress --sparse $BAK_DIR/ $remote/vmbackup || { echo >&2 "Synchronization failed for $remote"; continue; }

done

exit 0