Script to manage auto-snapshots for specified VirtualBox VM. Able to rotate snapshots, create, restore and delete ones.

vm-auto-snapshot.sh

#!/bin/bash
# vim: ts=4 sw=4 et

#
# Auto-snapshotting script intended to be cron'ed,
# taking automatic snapshots of particular VM, logging that actions,
# and providing means of restoring specific snapshots.
# Included with functionality of rotating them (like logrotate).
#
# Example cron entry for this script:
#   0 12 * * * user /home/user/vm-auto-snapshot.sh -f -t
#
# Mariusz B., 2017
# v0.4
#

# -- CONFIGURATION --

# Machine's name to manage, if it's empty - one will have to specify "-n" parameter to this script
VM_NAME=""

# Max number of snapshots to keep
SNAPSHOTS_ROTATE=3

# This file must be writeable for the owner of this script!
LOG_FILE="/var/log/vm-auto-snapshots.log"

# -- CONFIGURATION --


function usage {
    echo "Usage: ./vm-auto-snapshot.sh [options]"
    echo
    echo -e "\t-n <name>\tOperate on this particular VM"
    echo -e "\t-f\t\tTake forced action (no questions, batch mode)"
    echo -e "\t-t\t\tTake auto snapshot"
    echo -e "\t-r <num>\tRestore snapshot with number <num>"
    echo -e "\t-d <num>\tDelete snapshot with number <num>"
    echo -e "\t-l\t\tList auto-snapshots."
    echo -e "\t-h\t\tThis cruft"
    echo
}

function get_snapshots {
    S=$(vboxmanage snapshot "$VM_NAME" list --machinereadable | grep auto-snapshot)
    ret=$?
    if [ "$S" == "This machine does not have any snapshots" ]; then
        exit 0
    elif [ $ret -ne 0 ]; then
        >&2 echo "[!] Listing VM's snapshots has failed. Maybe you specified wrong VM's name? Currently used: '$VM_NAME'"
        exit 1
    fi
    echo "$S" | grep -E '^SnapshotName.*=' | pcregrep -o1 '.+="([^"]+)"'
}

function rename_snapshots {
    _snapshots=$(get_snapshots)
    _new_num=1

    for snap in $(echo "$_snapshots")
    do 
        _num=$(echo "$snap" | cut -d- -f3)
        _to_name="auto-snapshot-$_new_num"
        vboxmanage snapshot "$VM_NAME" edit "auto-snapshot-$_num" --name "$_to_name" 2> /dev/null
        ((_new_num++))
    done
}


BATCH=0
ACTION=0    # 0 - list, 1 - take, 2 - restore, 3 - delete
RESTORE_NUM=0

while [[ $# -ge 1 ]]
do
    key="$1"

    case $key in
        -f)
            BATCH=1
        ;;

        -t)
            ACTION=1
        ;;

        -r)
            ACTION=2
            RESTORE_NUM=$2
            
            if [ -z "$2" ]; then
                echo "[!] You did not specify snapshot number to restore."
                exit 1
            fi
            shift
        ;;

        -d)
            ACTION=3
            RESTORE_NUM=$2
            
            if [ -z "$2" ]; then
                echo "[!] You did not specify snapshot number to delete."
                exit 1
            fi
            shift
        ;;

        -n)
            if [ -z "$2" ]; then
                echo "[!] You did not specify name of VM to operate on."
                exit 1
            fi

            VM_NAME="$2"
            shift
        ;;

        -l)
            ACTION=0
        ;;

        -h)
            usage
            exit
        ;;

        *)
            echo "[!] Unknown option: $1"
            usage
            exit 1
        ;;
    esac
    shift
done

if [ -n "$LOG_FILE" ] && [ $BATCH -eq 1 ]; then
    exec > >(tee -i -a $LOG_FILE)
    exec 2>&1
fi

if [ -z "$VM_NAME" ]; then
    echo "[!] Please provide VM_NAME either via variable within this script or via -n parameter."
    exit 1
else
    if [ $BATCH -eq 1 ]; then
        echo
        echo "[+] Starting auto-snapshot tool on $VM_NAME ($(date))..."
    else
        echo "[+] Operating on: $VM_NAME"
    fi
fi

date=$(date +'%d.%m.%y-%H:%M')
snapshots=$(get_snapshots)

if [ $? -eq 1 ] && [ -z "$snapshots" ]; then
    echo "[!] Could not get snapshots"
    echo -e "$snapshots"
    exit 1
fi

snapshots_num=$(echo -e "$snapshots" | wc -l)
last_num=$(echo -e "$snapshots" | sort -nr | head -1 | cut -d- -f3)
first_num=$(echo -e "$snapshots" | sort -n | head -1 | cut -d- -f3)

if [ -z "$last_num" ]; then
    last_num=0
fi

if [ -z "$snapshots" ]; then
    snapshots="<none>"
fi

((last_num++))
rotate_driven_rename=0

if [ $last_num -ge $SNAPSHOTS_ROTATE ] && [ $snapshots_num -ge $SNAPSHOTS_ROTATE ]; then
    last_num=$SNAPSHOTS_ROTATE
    rotate_driven_rename=1  

elif [ $last_num -ge $SNAPSHOTS_ROTATE ] && [ $snapshots_num -lt $SNAPSHOTS_ROTATE ]; then
    last_num=$((snapshots_num+1))
    rotate_driven_rename=1  
fi

new_name="auto-snapshot-$last_num"
description="Auto snapshot taken: $date"

if [ $BATCH -eq 1 ]; then
    echo "[+] There are at the moment: $snapshots_num auto snapshots."
    echo
fi

if [ $ACTION -eq 0 ]; then
    echo "[?] Snapshots taken automatically so far: "
    echo "--------------------"
snapshots_raw=$(vboxmanage snapshot "$VM_NAME" list --machinereadable | grep -v Current)
    IFS=$'\n'
    for snap in $snapshots
    do
            snap_desc=$(echo -e "$snapshots_raw" | grep -A3 "$snap" | pcregrep -o1 'SnapshotDescription.*="([^"]+)"' | head -1)	
            if [ -n "$snap_desc" ]; then
                    echo -e "$snap ($snap_desc)"
            else
                    echo -e "$snap"
            fi
    done

elif [ $ACTION -eq 1 ]; then

    if [ $snapshots_num -ge $SNAPSHOTS_ROTATE ]; then
        echo "[?] Snapshots rotation needed - reached number of $SNAPSHOTS_ROTATE snapshots."

        _snapshots_num=$snapshots_num
        _first_num=$(echo -e "$snapshots" | sort -n | head -1 | cut -d- -f3)

        while [ $_snapshots_num -ge $SNAPSHOTS_ROTATE ]
        do
            echo "[.] Removing snapshot: auto-snapshot-$_first_num (left snapshots: $_snapshots_num)"
            vboxmanage snapshot "$VM_NAME" delete "auto-snapshot-$_first_num"

            _snapshots=$(get_snapshots)
            _snapshots_num=$(echo -e "$_snapshots" | wc -l)
            _first_num=$(echo -e "$_snapshots" | sort -n | head -1 | cut -d- -f3)
        done

        echo
    fi

    if [ $BATCH -eq 0 ]; then
        read -p "Do you want to take a new snapshot '$new_name' [y/N]? " -n 1 -r
        echo

        if [[ ! $REPLY =~ ^[Yy]$ ]]
        then
            [[ "$0" = "$BASH_SOURCE" ]] && exit 1 || return 1
        fi

        echo
        echo "[?] Taking snapshot $new_name ($description)..."
        vboxmanage snapshot "$VM_NAME" take $new_name --description "$description"
    else
        echo "[?] Taking snapshot $new_name ($description)..."
        vboxmanage snapshot "$VM_NAME" take $new_name --description "$description"
    fi

    echo

    if [ $rotate_driven_rename -eq 1 ] ; then
        rename_snapshots
    fi

elif [ $ACTION -eq 2 ]; then

    num=$RESTORE_NUM
    restore_name="auto-snapshot-$num"

    if [ -z "$(echo -e "$snapshots" | grep auto-snapshot-$num)" ]; then
        echo "[!] There is no auto-snapshot with number: $num. Failure, quitting."
        exit 1
    fi

    if [ $BATCH -eq 0 ]; then
        read -p "Do you want to restore snapshot '$restore_name' [y/N]? " -n 1 -r
        echo

        if [[ ! $REPLY =~ ^[Yy]$ ]]
        then
            [[ "$0" = "$BASH_SOURCE" ]] && exit 1 || return 1
        fi

        echo
        echo "[?] Restoring snapshot $restore_name..."
        vboxmanage snapshot "$VM_NAME" restore "$restore_name"
    else
        echo "[?] Restoring snapshot $restore_name..."
        vboxmanage snapshot "$VM_NAME" restore "$restore_name"
    fi

elif [ $ACTION -eq 3 ]; then

    num=$RESTORE_NUM
    restore_name="auto-snapshot-$num"

    if [ -z "$(echo -e "$snapshots" | grep auto-snapshot-$num)" ]; then
        echo "[!] There is no auto-snapshot with number: $num. Failure, quitting."
        exit 1
    fi

    if [ $BATCH -eq 0 ]; then
        read -p "Do you want to DELETE snapshot '$restore_name' [y/N]? " -n 1 -r
        echo

        if [[ ! $REPLY =~ ^[Yy]$ ]]
        then
            [[ "$0" = "$BASH_SOURCE" ]] && exit 1 || return 1
        fi

        echo
        echo "[?] Deleting snapshot $restore_name..."
        vboxmanage snapshot "$VM_NAME" delete "$restore_name"
    else
        echo "[?] Deleting snapshot $restore_name..."
        vboxmanage snapshot "$VM_NAME" delete "$restore_name"
    fi
fi


if [ $BATCH -eq 1 ]; then
    echo
    echo "[+] Script finished ($(date))"
    echo
fi