Linux-KVM Management: Offline Migration

#!/bin/bash
# chkconfig:
# description:
#
#: Script Name    : vmmigrate.sh
#: Version    : 0.9.3
#: Author    : Matthew Mattoon - http://blog.allanglesit.com
#: Date Created    : August 1, 2011
#: Date Updated    : February 20, 2013
#: Description    : Offline Migration script for KVM Virtual Machines
#: Examples    : vmmigrate.sh -n VMNAME -r REMOTEHOST -v REMOTEVGNAME -c COMPRESSIONLEVEL[0-9] -t -s
#:         : vmmigrate.sh -n testvm -r testhost -v testhost -c 0 -t -s

usage()
{
cat /,//p" | sed -n '/source file/p' | cut -d "'" -f 2`

if [[ -n "$disklist" ]]
then
echo "Script has detected non-LVM disks in use.  This script cannot safely process non-LVM disks."
exit
fi

cdlist=`virsh dumpxml ${vmname} | sed -n "//,//p" | sed -n '/source file/p' | cut -d "'" -f 2`

if [[ -n "$cdlist" ]]
then
echo "The safety checks have detected an ISO file attached to this virtual machine.  Migration will strip the ISO image from the configuration of the virtual machine.  If you would like to resolve this in a different way please do not proceed with the migration when given the opportunity to proceed."
fi

user="root"
basesize="1024"

if [[ -n "$tempkey" ]]
then
key="/root/.ssh/vmmigrate_id_${vmname}"
publickey="/root/.ssh/vmmigrate_id_${vmname}.pub"
authkeys="/root/.ssh/authorized_keys"
ssh-keygen -t rsa -q -f ${key} -N ''
chmod 600 ${key}
chmod 600 ${publickey}
pubkeystring=`cat ${publickey} | sed -e 's/\//.*/g'`
ssh-copy-id -i ${publickey} root@${remotehost} 2>&1 1>/dev/null

sshstring="ssh -i ${key} ${user}@${remotehost}"
else
sshstring="ssh ${user}@${remotehost}"
fi

xmlfile="/tmp/${vmname}.xml"

lvlist=`virsh dumpxml ${vmname} | sed -n "//,//p" | sed -n '/source dev/p' | cut -d "'" -f 2`
localvgname=`virsh dumpxml ${vmname} | grep "_boot" | cut -d "'" -f 2 | cut -d "/" -f 3`
localvg=`vgs ${localvgname} -o vg_name,vg_extent_size,vg_free_count | grep ${localvgname}`
remotevg=`${sshstring} "vgs ${remotevgname} -o vg_name,vg_extent_size,vg_free_count" | grep ${remotevgname}`
localvgextentsize=`echo ${localvg} | tr -s [:space:] | cut -d " " -f 2 | cut -d "." -f 1`
remotevgextentsize=`echo ${remotevg} | tr -s [:space:] | cut -d " " -f 2 | cut -d "." -f 1`
remotevgfreeextents=`echo ${remotevg} | tr -s [:space:] | cut -d " " -f 3`
remotevgcheck=`expr $remotevgextentsize \* $remotevgfreeextents`
remotevgcheck=`expr $remotevgcheck \/ $basesize`

for lv in ${lvlist}
do
lvextents=`lvdisplay ${lv} -c | cut -d ":" -f 8`
lvsize=`expr $lvextents \* $localvgextentsize`
lvsizetotal=`expr $lvsizetotal + $lvsize`
done

lvsizetotal=`expr $lvsizetotal \/ $basesize`

if [ "$remotevgcheck" -lt "$lvsizetotal" ]
then
echo "The remote Volume Group does not contain the free space necessary for the creation of all Logical Volumes for this migration, script must exit."
echo "Cleaning up temporary ssh keys..."
${sshstring} "cat ${authkeys} | sed -e '/$pubkeystring/d' > ${authkeys}"
rm ${key} ${publickey}
exit
fi

read -p "Would you like to begin the migration of ${vmname} to ${remotehost}?  (y/n)  "
if [ "$REPLY" != "y" ]
then
echo "User chose to abort migration."
if [[ -n "$tempkey" ]]
then
echo "Cleaning up temporary ssh keys..."
${sshstring} "cat ${authkeys} | sed -e '/$pubkeystring/d' > ${authkeys}"
rm ${key} ${publickey}
fi
echo "Exiting..."
exit
fi

echo "=============== BEGIN DATA MOVES ==============="
echo ""

for lv in ${lvlist}
do
lvname=`basename ${lv}`
lvextents=`lvdisplay ${lv} -c | cut -d ":" -f 8`
lvsize=`expr $lvextents \* $localvgextentsize`
remotelvcheck=`${sshstring} "lvs /dev/${remotevgname}/${lvname} 2>&1"`
if [ "$remotelvcheck" == "  One or more specified logical volume(s) not found." ]
then
echo "Creating Logical Volume ${lvname} on ${remotehost}."
${sshstring} "lvcreate -L${lvsize}M ${remotevgname} -n ${lvname} 2>&1 > /dev/null"
else
echo "Logical Volume (${lvname}) already exists on the remote host, for the safety of your data and system, this script will not overwrite a Logical Volume which it did not create, script must exit."
exit
fi
localpvtest=`hash pv 2>&- || { echo >&2 "pv not installed"; } 2>&1`
remotepvtest=`${sshstring} "hash pv 2>&- || { echo >&2 "pv not installed"; } 2>&1"`
if [[ -n "$localpvtest" ]] || [[ -n "$remotepvtest" ]]
then
message="Transferring ${lvname} to ${remotehost}."
message2="Progress is not available, please install pv for progress..."
if [ "$compressionlevel" -eq "0" ]
then
echo "${message}  With no compression.  ${message2}"
dd if=${lv} 2>/dev/null | ${sshstring} "dd of=/dev/${remotevgname}/${lvname} 2>/dev/null"
else
echo "${message}  With compression.  ${message2}"
dd if=${lv} 2>/dev/null | gzip -${compressionlevel} | ${sshstring} "gunzip | dd of=/dev/${remotevgname}/${lvname} 2>/dev/null"
fi
else
message="Transferring ${lvname} to ${remotehost}."
if [ "$compressionlevel" -eq "0" ]
then
echo "${message}  With no compression..."
dd if=${lv} 2>/dev/null | pv -tpreb -N ${lvname} -s ${lvsize}M | ${sshstring} "dd of=/dev/${remotevgname}/${lvname} 2>/dev/null"
else
echo "${message}  With compression..."
dd if=${lv} 2>/dev/null | pv -tpreb -N ${lvname} -s ${lvsize}M | gzip -${compressionlevel} | ${sshstring} "gunzip | dd of=/dev/${remotevgname}/${lvname} 2>/dev/null"
fi
fi
done

echo ""
echo "================ END DATA MOVES ================"

virsh dumpxml ${vmname} | sed "/\|vnet\|\|\|//g" | sed "s/${localvgname}/${remotevgname}/g" > ${xmlfile}

echo "Transferring configuration file."
if [[ -n "$tempkey" ]]
then
scp -i ${key} ${xmlfile} ${user}@${remotehost}:${xmlfile} #2&>1 > /dev/null
else
scp ${xmlfile} ${user}@${remotehost}:${xmlfile} #2&>1 > /dev/null
fi
rm ${xmlfile}

echo "Defining domain from configuration."
${sshstring} "virsh define ${xmlfile}; rm ${xmlfile}" #2&>1 > /dev/null

if [[ -n "$startoncomplete" ]]
then
${sshstring} "virsh start ${vmname}" #2&>1 > /dev/null
fi

if [[ -n "$tempkey" ]]
then
echo "Cleaning up temporary ssh keys..."
${sshstring} "cat ${authkeys} | sed -e '/$pubkeystring/d' > ${authkeys}"
rm ${key} ${publickey}
fi