vmtools/vmbackup

#!/bin/sh
# vim: tabstop=4 shiftwidth=4 expandtab

# 
# This script performs backups of VMs filesystems. It achieves this by
# ssh into the VM and using dump with FSS to get a consistent point
# in time snapshot.
#

# Locate libraries
script_dir="$(dirname "$(readlink -f "$0")")"
lib_dir="$script_dir/lib"

# Include libraries
. $lib_dir/common.sh

# Exit if not running under root
if [ $(id -u) -ne 0 ]; then
    log crit "This script requires root permissions."
    exit 1
fi

# Read configuration
. $lib_dir/vmtoolsrc
if [ -r $HOME/.vmtoolsrc ]; then
	. $HOME/.vmtoolsrc
	log info "Loaded local configuration from $HOME/.vmtoolsrc"
else
	log warning "Local configuration not found, using defaults"
fi

# Default options
gptlabel_opt=""
backupset_opt=""
targetdir_opt=""

# Globals
GLOBAL_FILE_LABEL_PREVIOUS=/var/tmp/label.prev

configure() {
	log info "Configuration started"
	if [ ! -w $HOME/.vmtoolsrc ]; then
		log notice "Create new local configuration from defaults"
		cp $lib_dir/vmtoolsrc $HOME/.vmtoolsrc
	fi
	vi $HOME/.vmtoolsrc
	log info "Configuration finished"
}

#
# Properly handle Ctrl+C
#
trap exit_handler 2

#
# Exit handler
#
exit_handler() {
    log warning "Ctrl+C received, shutting down ..."
    sync
    umount_target
    release_lock
    exit 2
}

#
# Mount the target filesystem
#
mount_target() {
	local gptlabel=$1
	local targetdir=$2     
    mount -o log NAME=$gptlabel $targetdir
    if [ $? -gt 0 ]; then
		log alert "Mount of target filesystem failed."
		release_lock
        exit 1
    fi
}

#
# Check if label (UUID) and backup set are present
#
check_labels() {
	local targetdir=$1
    if [ ! -f $targetdir/.label ]
    then
        log warning "Missing target label"
        return 1
    fi
    
    if [ ! -f $targetdir/.backupset ]
    then
        log warning "Missing target backup set"
        return 2
    fi
    echo `cat $targetdir/.backupset`
}

#
# Label Target 
#
label_target() {
	local targetdir=$1
	local backupset=$2
    echo $backupset > $targetdir/.backupset
    local uuid=`uuidgen`
    echo $uuid > $targetdir/.label
    log info "Labeled target with ID $uuid and assignet to backup set $backupset"
}

#
# Detect Target Media Change 
#
detect_media_change() {
	local targetdir=$1
    local label_current=`cat $targetdir/.label`
    local label_previous=`cat $GLOBAL_FILE_LABEL_PREVIOUS 2>/dev/null`

    if [ -z $label_previous ];then
        log warning "No cached target ID, assuming target has changed"
        echo $label_current > $GLOBAL_FILE_LABEL_PREVIOUS
        return 1
    fi

    # If label not equal - new drive or drive swapped
    if [ $label_current != $label_previous ]; then
        log notice "Target changed from $label_previous to $label_current"
        echo $label_current > $GLOBAL_FILE_LABEL_PREVIOUS
        return 1
    else
        log notice "Reusing target $label_current"
        return 0
    fi
}

#
# Clean Target 
#
clean_target() {
	local targetdir=$1
    log notice "Cleaning target ..."
    rm -f $targetdir/*.dump
}

#
# Get next dump sequence for given dumpbase
#
get_next_sequence()
{
    local dumpbase=$1
	local level_last=-1
    local level=-1

    for dump_file in `ls $dumpbase.*.dump 2>/dev/null`
    do
        level=`echo $dump_file |cut -d "." -f 2`
        if [ $level -gt $level_last ]
        then
            level_last=$level
        fi
    done
    echo `expr $level_last + 1`
}

#
# Unmount the target filesystem
#
umount_target()
{
	local targetdir=$1
    umount $targetdir
}

dump_filesystems() {
	local fqhostname=$1
	local targetdir=$2
	local backupset=$3
	local hostname=`echo $fqhostname|cut -d. -f1`
        
    for filesystem in $(ssh user@$fqhostname "awk '\$5 == "$backupset" { print \$2 }' /etc/fstab"); do
		local name=$(basename $filesystem)
		if [ $name = "/" ]; then
			name="root"
		fi
		local dumpbase="${targetdir}/${hostname}_${name}"
		local next_seq=$(get_next_sequence $dumpbase)
		local dumpname=${dumpbase}.${next_seq}.dump
		local dump_level='i'
		if [ $next_seq = '0' ]; then
			dump_level='0'
		fi
		log notice "Dump of filesystem $filesystem to $dumpname started."
		ssh user@$fqhostname "doas /sbin/dump -X -h 0 -b 64 -${dump_level}auf - $filesystem" | dd bs=4m oflag=creat,direct of=$dumpname msgfmt=quiet
		if [ $? -gt 0 ]; then
			log alert "Dump of filesystem $filesystem to $dumpname failed."
			release_lock
			exit 2
		fi
		log notice "Dump of filesystem $filesystem to $dumpname completed."
	done	
}

#
# Print usage
#
usage() {
	echo "Usage: $0 command [options] <hostname>"
	echo
	echo "Commands:"
	echo "  auto                   Backup given host and automatically choose settings"
	echo "  manual                 Backup given host with manual settings"
	echo "  label                  Label the backup media"
	echo "  configure              Configure the backup settings"	
	echo
	echo "Options:"
	echo "  -l <gptlabel>		   Mount filesytem with GPT label and use as backup target"
	echo "  -s <backupset>         Specify the number of backup set"
	echo "  -t <targetdir>         Specify the target dir for the dump"
	echo
	exit 1
}

#
# CLI
#
command=$1

# No command provided
if [ -z "$command" ]; then
  echo "No command provided"
  usage
fi

shift

# Invalid command provided
case "$command" in
  auto|manual|label|configure)
    ;;
  *)
    echo "Invalid command: $command"
    usage
    ;;
esac

# Process options
while getopts "l:s:t:" option; do
  case $option in
    l)
      gptlabel_opt=$OPTARG
      ;;
    s)
      backupset_opt=$OPTARG
      ;;
    t)
      targetdir_opt=$OPTARG
      ;;
    \?)      
      usage
      ;;
  esac
done
shift $((OPTIND - 1))

hostname_arg=$1

# Process commands
case "$command" in
	label)
		if [ -z "$backupset_opt" ]; then
			echo "backupset option is required for 'label' command."
			usage
		fi
		if [ -z "$gptlabel_opt" ]; then
			echo "gptlabel option is required for 'label' command"
			usage
		fi
	
		aquire_lock
		mnt=`mktemp -d`
		mount_target $gptlabel_opt $mnt
		if [ $? -gt 0 ]; then
			log alert "Target media not present, exiting."
			release_lock
			exit 1
		fi
		label_target $mnt $backupset_opt
		umount_target $mnt
		release_lock
		;;
	auto)
		if [ -z "$hostname_arg" ]; then
			echo "Hostname argument is required for 'auto' command"
			usage
		fi
		if [ -z "$gptlabel_opt" ]; then
			echo "gptlabel option is required for 'auto' command"
			usage
		fi
	
		aquire_lock
		log info "Backup of host $hostname_arg started."
	
		mnt=`mktemp -d`
		mount_target $gptlabel_opt $mnt
		
		backupset=$(check_labels $mnt)
		if [ $? -gt 0 ]; then
			log alert "Target media not usable, exiting."
			umount_target $mnt
			release_lock
			exit 1
		fi
		
		log notice "Backupset selected: $backupset"
    		
		detect_media_change $mnt
		media_changed=$?
		if [ $media_changed -eq 1 ]; then
			clean_target		
		fi
		
		dump_filesystems $hostname_arg $mnt $backupset
		
		umount_target $mnt
		rmdir $mnt
		
		release_lock
		log info "Backup of host $argument finished."
		;;
	manual)
		if [ -z "$hostname_arg" ]; then
			echo "Hostname argument is required for 'manual' command"
			usage
		fi
		if [ -z "$backupset_opt" ]; then
			echo "backupset option is required for 'manual' command"
			usage
		fi
		if [ -z "$targetdir_opt" ]; then
			echo "targetdir option is required for 'manual' command"
			usage
		fi
		
		aquire_lock
		log info "Backup of host $hostname_arg started."
	
		dump_filesystems $hostname_arg $targetdir_opt $backupset_opt
		
		release_lock
		log info "Backup of host $hostname_arg finished."	
		;;
	configure)
		configure
		;;
esac