backup-vm

#!/bin/bash

VERSION=0.1
CONFIG=/etc/kvm-backup.conf
SCRIPT=$(basename "$0")
TIME_SHUTDOWN=60
VERBOSE=0

function usage {
        echo "Usage: ${SCRIPT} [-t|-c|-h|-v] -n" 2>&1
        echo '   -n    virtual machine name'
        echo '   -t    time in seconds to wait virtual machine shutdown'
        echo '   -c    configuration file path'
        echo '   -v    verbose output'
        echo '   -h    shows this help and exit'
        echo '   -V    shows version and exit'
        exit 1
}

if [[ ${#} -eq 0 ]]; then
   usage
fi

# Define list of arguments expected in the input
optstring=":n:t:c:hvV"

while getopts ${optstring} arg; do
  case "${arg}" in
    n) vm="${OPTARG}" ;;
    t) TIME_SHUTDOWN=${OPTARG} ;;
    c) CONFIG=${OPTARG} ;;
    h) usage ;;
    v) VERBOSE=1 ;;
    V) echo "Version: ${VERSION}"
       exit 0 
       ;;
    \?)
      echo "Invalid option: -${OPTARG}."
      echo
      usage
      ;;
    :)
      echo "Option -$OPTARG requires an argument." >&2
      exit 1
      ;;
  esac
done

function log_message {
  if [ "$1" = "error" ]; then
    logger -t "${SCRIPT}" -p "local3.err" "$2"
    if [ ${VERBOSE} -eq 1 ]; then
      echo "$2"
    fi 
  elif [ "$1" = "info" ]; then
    logger -t "${SCRIPT}" -p "local3.info" "$2"
    if [ ${VERBOSE} -eq 1 ]; then
      echo "$2"
    fi
  fi
}

function get_qemu_version {
    rpm_bin=$(/usr/bin/which rpm)
    qemu_version=$(${rpm_bin} -q qemu-img |cut -d"-" -f3|cut -d"." -f1)

    if [ "${qemu_version}" -ge 3 ]; then
        qemu_options='-Wc -O qcow2'
        log_message "info" "qemu version ${qemu_version} or higher detected"
        log_message "info" "using options ${qemu_options}"
    else
        qemu_options='-c -O qcow2'
        log_message "info" "qemu version ${qemu_version} or lower detected"
        log_message "info" "using options ${qemu_options}"
    fi
}

function check_vm_exists {
  if ! virsh list --all | grep -q "${vm}"; then
      log_message "error" "virtual machine ${vm} not found"
      exit 1
  else
    log_message "info" "virtual machine ${vm} found"
  fi
}

function load_config {
  if [ ! -f "${CONFIG}" ];
  then
    echo "Configuration file doesn't exits"
    log_message "error" "Configuration file doesn't exits ${CONFIG}"
    exit 2
  fi
  log_message "info" "Loading configuration file ${CONFIG}"
  # shellcheck source=/dev/null
  source "${CONFIG}"
}

function prepare_dirs {
  timestamp=$(date +%Y%m%d%H%M%S)
  if [ ! -d "${NFSEXPORT}/${vm}-${timestamp}" ]; then
    log_message "info" "Creating backup directory ${NFSEXPORT}/${vm}-${timestamp}"
    if ! mkdir -p "${NFSEXPORT}/${vm}-${timestamp}"; then
      log_message "error" "Error creating backup directory ${NFSEXPORT}/${vm}-${timestamp}"
      exit 3
    fi
  fi
}

function make_config_backup {
  log_message "info" "Creating configuration backup in ${NFSEXPORT}/${vm}-${timestamp}/${vm}.xml"
  
  if ! virsh dumpxml "${vm}" > "${NFSEXPORT}/${vm}-${timestamp}/${vm}.xml"; then
    log_message "error" "Error creating configuration backup in ${NFSEXPORT}/${vm}-${timestamp}/${vm}.xml"
    exit 4
  fi
}

function get_disks {
  log_message "info" "Getting disks"
  for disk in $(virsh domblklist --details "${vm}"|awk '/dev/ {print $4}' | xargs); do
    disks+=("${disk}")
    disks_names+=("${disk##*/}")
    log_message "info" "Disks: ${disk} found for vm ${vm}"
  done
}

function get_vgs {
  log_message "info" "Getting volumes groups"
  for disk in "${disks[@]}"; do
    vgs+=( "$(lvdisplay -v "${disk}" 2>/dev/null|awk '/VG/ {print $3}')" )
    disk_size+=( "$(lvdisplay -v "${disk}" 2>/dev/null|awk '/LV Size/ {print $3}'|awk -F"." '{print $1}')" )
  done
  for ((i=0; i<${#vgs[@]}; i++)); do
    log_message "info" "Volume group ${vgs[$i]} found for disk ${disks[$i]} with size ${disk_size[$i]}"
  done
}

function get_vm_status {
  log_message "info" "Getting vm status"
  vm_status=$(virsh domstate "${vm}")
}

function shutdown_vm {
  get_vm_status
  if [ "${vm_status}" = "shut off" ]; then
    log_message "info" "Virtual machine ${vm} is ${vm_status}"
  else
    log_message "info" "Virtual machine ${vm} is ${vm_status}"
    log_message "info" "Shutting down virtual machine ${vm}"
    if ! virsh shutdown "${vm}" &>/dev/null; then
      log_message "error" "Error shutting down virtual machine ${vm}"
      exit 5
    fi
    log_message "info" "Waiting ${TIME_SHUTDOWN} seconds for virtual machine ${vm} to shutdown"
    sleep "${TIME_SHUTDOWN}"
    get_vm_status
  fi
}

function start_vm {
  log_message "info" "Starting virtual machine ${vm}"
  if ! virsh start "${vm}" &>/dev/null; then
    log_message "error" "Error starting virtual machine ${vm}"
    exit 7
  fi
}

function take_snapshot {
  for ((i=0; i<${#disks[@]}; i++)); do
    vg_free_space=$(vgdisplay "${vgs[$i]}" | awk '/Free/ {print $7}'|awk -F"." '{print $1}')
    log_message "info" "Checking volume group ${vgs[$i]} for free space"
    if [ "${vg_free_space}" -gt "${disk_size[$i]}" ]; then
      log_message "info" "Volume group ${vgs[$i]} has enough free space to take snapshot"
      if ! lvcreate -s -n "${disks_names[$i]}Snap" -L "${disk_size[$i]}G" "${disks[$i]}" &>/dev/null; then
        log_message "error" "Error taking snapshot of virtual machine ${vm}"
      exit 8
    fi
    else
      log_message "error" "Volume group ${vgs[$i]} has not enough free space to take snapshot"
      delete_snapshots
      start_vm
      exit 8
    fi
  done
  snapshots=$(lvdisplay |grep Snap|awk '/Path/ {print $3}' |xargs)
  start_vm
}

function delete_snapshots {
  for snapshot in "${snapshots[@]}"; do
    log_message "info" "Deleting snapshot ${snapshot}"
    if ! lvremove -f "${snapshot}" &>/dev/null; then
      log_message "error" "Error deleting snapshot ${snapshot}"
      exit 9
    fi
  done
}

function convert_to_qcow2 {
  for snap in ${snapshots}; do
    snap_name=$(echo "${snap}" | awk -F"/" '{print $NF}')
    log_message "info" "Converting snapshot ${snap} to qcow2"
    log_message "info" "Using command: qemu-img convert ${qemu_options} ${snap} ${NFSEXPORT}/${vm}-${timestamp}/${snap_name}.qcow2"
    if ! qemu-img convert "${qemu_options}" "${snap}" "${NFSEXPORT}/${vm}-${timestamp}/${snap_name}.qcow2"; then
      log_message "error" "Error converting snapshot ${snap} to qcow2"
      delete_snapshots
      exit 10
    fi
    delete_snapshots
  done
}

function main {
  load_config
  get_qemu_version
  check_vm_exists
  prepare_dirs
  make_config_backup
  get_disks
  get_vgs
  shutdown_vm
  if [ "${vm_status}" = "shut off" ]; then
    take_snapshot
    convert_to_qcow2
  else
    log_message "info" "Virtual machine ${vm} is not shut off"
    exit 6
  fi
  log_message "info" "Backup of virtual machine ${vm} completed"
  exit 0
}

# Main Script
main