Script for moving Xen virtual machine using only SSH, rsync and lvm

move-vm

#!/bin/bash
#
# Auteur : Hedi Nasr, Nicolas Carel
# Version : 1.2
# Description : script de deplacement de vm
# Prérequis:
#            - Hyperviseur: Xen
#            - LVM
#            - Nom des volumes: <nom-vm>-<disk|swap|data>
#
# Le script est à lancer depuis la machine de l'administrateur
##############################################################
# Workflow
# --------
#
# 1) L'administrateur se connecte en SSH sur l'hyperviseur
#    source en transférant l'agent SSH.
# 2) Snapshot de la machine virtuelle + tar du snapshot
# 3) Copie de la sauvegarde vers l'hyperviseur destination
# 4) Création de la nouvelle machine virtuelle (xen-create-image)
# 5) Extinction de l'ancienne machine + montage des disques en
#    locale.
# 6) rsync des données manquantes
# 7) Nettoyage
##############################################################
set -e # quitte le script a la moindre erreur

print_help() {
    cat <<EOF
Usage: move-vm [-h] [-n] [-s] [-f] [-v] <hyp_src> <vm> <hyp_dst> [vg_data]

       -h      affiche l'aide
       -n      dry-run, affiche seulement les commandes qui vont etre executes
       -s      synchro supplementaire
       -f      finalisation (la vm source sera arretee)
       -v      verbose
       hyp_src hyperviseur source
       vm      nom de la machine virtuelle a deplacer
       hyp_dst hyperviseur sur lequel sera installe la machine virtuelle
       vg_data nom du vg data (optionnel)
EOF
}

PRINT=
FINAL=0
VERBOSE=

while getopts ":hnsfv" opt; do
    case $opt in
	      h)
	          print_help
	          exit 0
	          ;;
	      n)
	          PRINT=echo
	          ;;
	      s)
            FINAL=1
            ;;
	      f)
            FINAL=2
            ;;
	      v)
		        VERBOSE="-v"
		        ;;
	      \?)
	          echo "Invalid option: -$OPTARG" >&2
	          print_help
	          exit 1
	          ;;
    esac
done

shift "$((OPTIND - 1))"

if [ "$#" -lt 3 ]; then
    print_help
    exit 1
fi

HYP_SRC="$1"
HYP_DST="$3"
VM="$2"
VG_DATA="$4"

# verifier si on est pas deja sur l'hyperviseur source
MY_HOST=`hostname`
if [ "${HYP_SRC%%.*}" == "$MY_HOST" ] ; then
  echo "Running move-vm on source hypervisor"
  SRC_CMD=""
else 
  SRC_CMD="ssh -AC root@${HYP_SRC} "
fi

# verifier si on est pas deja sur l'hyperviseur destination
if [ "${HYP_DST%%.*}" == "$MY_HOST" ] ; then
  echo "Running move-vm on destination hypervisor"
  DEST_CMD=""
else
  DEST_CMD="ssh root@${HYP_DST} "
fi

# il faut dans un premier temps recuperer les informations
# necessaires concernant les vm et les hyperviseurs
DISK_SIZE=`$SRC_CMD lvs | grep "$VM"-disk | awk '{ print $4 }' | sed 's/,/./'`
DATA_SIZE=`$SRC_CMD lvs | grep "$VM"-data | awk '{ print $4 }' | sed 's/,/./'`
SWAP_SIZE=`$SRC_CMD lvs | grep "$VM"-swap | awk '{ print $4 }' | sed 's/,/./'`

VG_SRC=`$SRC_CMD vgs | tail -1 | awk '{ print $1 }'`
VG_DST=`$DEST_CMD vgs | tail -1 | awk '{ print $1 }'`

# creation des volumes
# volume *-disk
if [ ! -z "$DISK_SIZE" ]; then
    echo "size of disk: $DISK_SIZE"
    if [ $FINAL == 0 ] ; then
        $PRINT $DEST_CMD lvcreate -n "$VM"-disk -L "$DISK_SIZE" "$VG_DST"
        $PRINT $DEST_CMD mkfs.ext4 /dev/"$VG_DST"/"$VM"-disk
    fi
    $PRINT $DEST_CMD mkdir /mnt/"$VM"-disk
    $PRINT $DEST_CMD mount /dev/"$VG_DST"/"$VM"-disk /mnt/"$VM"-disk
fi

# volume *-data
if [ ! -z "$DATA_SIZE" ]; then
    echo "size of disk: $DATA_SIZE"
    if [ $FINAL == 0 ] ; then
        if [ ! -z "$VG_DATA" ]
        then
            $PRINT $DEST_CMD lvcreate -n "$VM"-data -L "$DATA_SIZE" "$VG_DATA"
            $PRINT $DEST_CMD mkfs.ext4 /dev/"$VG_DATA"/"$VM"-data
            $PRINT $DEST_CMD mkdir /mnt/"$VM"-data
            $PRINT $DEST_CMD mount /dev/"$VG_DATA"/"$VM"-data /mnt/"$VM"-data
        else
            $PRINT $DEST_CMD lvcreate -n "$VM"-data -L "$DATA_SIZE" "$VG_DST"
            $PRINT $DEST_CMD mkfs.ext4 /dev/"$VG_DST"/"$VM"-data
            $PRINT $DEST_CMD mkdir /mnt/"$VM"-data
            $PRINT $DEST_CMD mount /dev/"$VG_DST"/"$VM"-data /mnt/"$VM"-data
        fi
    fi
fi

if [ ! -z "$SWAP_SIZE" ]; then
    echo "size of swap: $SWAP_SIZE"
    if [ $FINAL == 0 ] ; then
        $PRINT $DEST_CMD lvcreate -n "$VM"-swap -L "$SWAP_SIZE" "$VG_DST"
        $PRINT $DEST_CMD mkswap /dev/"$VG_DST"/"$VM"-swap
    fi
fi

# operation finale : extinction de la vm sur l'hyperviseur source
if [ $FINAL == 2 ] ; then
    $PRINT "shuting down $VM..."
    $PRINT $SRC_CMD xm shutdown -w "$VM"
fi


# snapshot + migration
if [ ! -z "$DISK_SIZE" ]; then
    $PRINT $SRC_CMD lvcreate --snapshot --size 1500m --name "$VM"-disk-snap /dev/"$VG_SRC"/"$VM"-disk
    $PRINT $SRC_CMD mkdir /mnt/"$VM"-disk-snap
    $PRINT $SRC_CMD mount -o ro /dev/"$VG_SRC"/"$VM"-disk-snap /mnt/"$VM"-disk-snap
    if [ "$DEST_CMD" == "" ] ; then
        echo "  Copying /mnt/${VM}-disk from ${HYP_SRC}:/mnt/${VM}-disk-snap ..."
        $PRINT $DEST_CMD rsync -a -H --numeric-ids $VERBOSE --delete root@"$HYP_SRC":/mnt/"$VM"-disk-snap/ /mnt/"$VM"-disk
    else
        echo "  Copying ${VM}-disk-snap to ${HYP_DST}:/mnt/${VM}-disk... "
        $PRINT $SRC_CMD rsync -a -H --numeric-ids $VERBOSE --delete /mnt/"$VM"-disk-snap/ root@"$HYP_DST":/mnt/"$VM"-disk
    fi
fi

if [ ! -z "$DATA_SIZE" ]; then
    $PRINT $SRC_CMD lvcreate --snapshot --size 1500m --name "$VM"-data-snap /dev/"$VG_SRC"/"$VM"-data
    $PRINT $SRC_CMD mkdir /mnt/"$VM"-data-snap
    $PRINT $SRC_CMD mount -o ro /dev/"$VG_SRC"/"$VM"-data-snap /mnt/"$VM"-data-snap
    if [ "$DEST_CMD" == "" ] ; then
        echo "  Copying /mnt/${VM}-data from ${HYP_SRC}:/mnt/${VM}-data-snap ..."
        $PRINT $DEST_CMD rsync -a -H --numeric-ids $VERBOSE --delete root@"$HYP_SRC":/mnt/"$VM"-data-snap/ /mnt/"$VM"-data
    else
        echo "  Copying ${VM}-data-snap to ${HYP_DST}:/mnt/${VM}-data... "
        $PRINT $SRC_CMD rsync -a -H --numeric-ids $VERBOSE --delete /mnt/"$VM"-data-snap/ root@"$HYP_DST":/mnt/"$VM"-data
    fi
fi

# fichier de configuration
if [ $FINAL == 0 ] ; then
    echo "  Copying /etc/xen/${VM}.cfg"
    if [ "$DEST_CMD" == "" ] ; then
        $PRINT scp root@"$HYP_SRC":/etc/xen/"$VM".cfg /etc/xen
    else
        $PRINT $SRC_CMD scp /etc/xen/"$VM".cfg root@"$HYP_DST":/etc/xen
    fi
fi

# verifier le paramétrage de noyau

# nettoyage sur la source
if [ ! -z "$DISK_SIZE" ]; then
    $PRINT $SRC_CMD umount /mnt/"$VM"-disk-snap
    $PRINT $SRC_CMD rmdir /mnt/"$VM"-disk-snap
    $PRINT $SRC_CMD lvremove -f /dev/"$VG_SRC"/"$VM"-disk-snap
fi

if [ ! -z "$DATA_SIZE" ]; then
    $PRINT $SRC_CMD umount /mnt/"$VM"-data-snap
    $PRINT $SRC_CMD rmdir /mnt/"$VM"-data-snap
    $PRINT $SRC_CMD lvremove -f /dev/"$VG_SRC"/"$VM"-data-snap
fi

# derniers reglages
echo " Installing kernel modules..."
$PRINT $DEST_CMD rsync -a $VERBOSE /lib/modules/ /mnt/${VM}-disk/lib/modules/

# verifier que la fstab est en ext4 pour les xvda*

# nettoyage sur la destination
if [ ! -z "$DISK_SIZE" ]; then
    $PRINT $DEST_CMD umount /mnt/"$VM"-disk
    $PRINT $DEST_CMD rmdir /mnt/"$VM"-disk
fi

if [ ! -z "$DATA_SIZE" ]; then
    $PRINT $DEST_CMD umount /mnt/"$VM"-data
    $PRINT $DEST_CMD rmdir /mnt/"$VM"-data
fi

# demarrage auto de la vm
#$PRINT $DEST_CMD ln -s /etc/xen/"$VM".cfg /etc/xen/auto/"$VM".cfg

# verifier le fichier de conf + xl create
echo "Migration (pas tout a fait) termine"
echo "- verifier la fstab destination (ext4!)"
echo "- verifier le fichier /etc/xen/$VM.cfg (kernel et bridge)"
echo "- eteindre la machine sur $HYP_SRC"
echo "- allumer la machine sur $HYP_DST"