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#!/bin/sh
#
# Copyright (C) 2009 Canonical, Ltd.
# Author: Jamie Strandboge <jamie@canonical.com>
# License: GPLv3
#
set -e
ustconf="$HOME/.uqt-vm-tools.conf"
if [ -s "$ustconf" ]; then
. "$ustconf"
else
echo "Could not find '$ustconf'"
exit 1
fi
# Find out our current directory
if [ -z "$UQT_VM_TOOLS" ]; then
UQT_VM_TOOLS=$(dirname $(readlink -f $0))
fi
. $UQT_VM_TOOLS/libvm.sh
abort_if_root
using_snapshots() {
cat << EOM
Once migrated, to start using snapshots:
$ vm-start -s vm1 vm2... (creates a new snapshot)
$ vm-start vm1 vm2... (used existing snapshot)
$ vm-stop -f vm1 vm2... (discards snapshot)
$ vm-stop vm1 vm2... (keeps snapshot)
$ vm-stop -u vm1 vm2... (commits changes to pristine image)
EOM
}
help() {
cat << EOM
Usage: vm-use-snapshots [-f] vm1 vm2...
This will move all disk images in the specified VM from <path>/<disk>.qcow2
to <path>/<disk>.pristine.qcow2, then update the domain XML to use
cache='writeback' for all qemu qcow2 disks defined in the XML. The libvirt
XML will still point to <path>/<disk>.qcow2, but when using 'vm-start -s',
qemu-img will create a new disk file (ie snapshot) at <path>/<disk>.qcow2
using <path>/<disk>.pristine.qcow2 as the backing store.
Specifying the '-f' will force conversion from a raw disk to a qcow2 with
snapshots without further confirmation and will delete the original raw
disk.
EOM
using_snapshots
}
# update_disk_cache() updates all qemu disks of type 'qcow2' to use the
# 'writeback' cache method, for performance reasons. See the '-drive' option
# in 'man qemu'. This is the wame behavior as when using qemu -snapshot
# directly.
update_disk_cache() {
tmp=`mktemp -d`
err=
virsh dumpxml "$1" | while read line ; do
if echo "$line" | grep -q "<driver name='qemu' type='qcow2'" ; then
echo "$line" | sed -e "s/cache='.*'//" -e "s#/># cache='writeback'/>#" >> "$tmp/xml"
continue
fi
echo "$line" >> "$tmp/xml"
done
virsh define "$tmp/xml" > "$tmp/output" 2>&1 || {
echo "Could not update domain:"
cat "$tmp/output"
cat "$tmp/xml"
err="yes"
}
rm -rf "$tmp"
if [ -n "$err" ]; then
exit 1
fi
}
convert_disk() {
disk="$1"
converted="$2"
if qemu-img info "$disk" | grep -q "file format: raw" ; then
if [ -f "$converted" ]; then
echo "WARN: '$converted' already exists. Skipping" >&2
return 1
fi
echo "INFO: Creating qcow2 from '$disk'"
qemu-img convert -f raw "$disk" -O qcow2 "$converted"
if qemu-img info "$converted" | grep "file format: qcow2" ; then
echo "INFO: qcow2 created. Deleting '$disk'"
rm -f "$disk"
else
echo "ERROR: could not convert disk" >&2
return 1
fi
else
echo "WARN: '$disk' is not in raw format. Skipping" >&2
return 1
fi
}
convert_xml() {
machine="$1"
disk="$2"
converted="$3"
tmp=`mktemp -d`
err=
echo "INFO: Updating xml to use '$converted' of type 'qcow2'"
virsh dumpxml "$machine" | tr '\n' ' ' | sed "s#<driver name='qemu' type='raw'/>\( *\)<source file='$disk'/>#<driver name='qemu' type='qcow2'/>\\1<source file='$converted'/>#" > "$tmp/xml" || return 1
virsh define "$tmp/xml" > "$tmp/output" 2>&1 || {
echo "Could not update domain:"
cat "$tmp/output"
cat "$tmp/xml"
err="yes"
}
rm -rf "$tmp"
if [ -n "$err" ]; then
return 1
fi
}
if [ -z "$1" ] || [ "$1" = "-h" ] || [ "$1" = "--help" ] ; then
help
exit 1
fi
force_conversion=
if [ "$1" = "-f" ] || [ "$1" = "--force" ] ; then
force_conversion="yes"
shift
fi
errors=""
performed_migration=""
for machine in "$@"; do
disks=`get_disks $machine`
if [ -z "$disks" ]; then
echo "WARN: Could not find any disks. Skipping snapshot preparation." >&2
errors="yes"
continue
fi
if vm_running "$machine" ; then
echo "WARN: '$machine' still running. Skipping snapshot preparation." >&2
errors="yes"
continue
fi
# go through once and make sure we can safely snapshot
use_snapshot="yes"
for d in $disks; do
real=`readlink -f "$d"`
dir=`dirname "$real"`
bn=`basename "$real" .qcow2`
pristine="$dir/$bn.pristine.qcow2"
if [ ! -e "$real" ]; then
echo "WARN: '$real' does not exist. Skipping snapshot preparation." >&2
use_snapshot="no"
break
fi
if ! echo "$real" | egrep -q '.qcow2$' ; then
converted="`echo \"$real\" | sed 's/\.[a-zA-Z]\+$//'`.qcow2"
if [ "$force_conversion" = "yes" ]; then
if ! convert_disk "$real" "$converted" ; then
use_snapshot="no"
errors="yes"
break
fi
if ! convert_xml "$machine" "$real" "$converted" ; then
use_snapshot="no"
errors="yes"
break
fi
# update the disks for this machine, now that we have adjusted the XML
disks=`get_disks $machine`
if [ -z "$disks" ]; then
echo "WARN: Could not find any disks. Skipping snapshot preparation." >&2
use_snapshot="no"
errors="yes"
break
fi
else
echo "WARN: File extension for '$real' is not 'qcow2'. Skipping snapshot preparation." >&2
echo "" >&2
echo "To convert, use something like:" >&2
echo "$ qemu-img convert -f raw '$real' -O qcow2 '$converted'" >&2
echo "$ qemu-img info '$converted'" >&2
echo "$ rm -f '$real'" >&2
echo "" >&2
echo "Then update your domain XML accordingly." >&2
use_snapshot="no"
break
fi
fi
if [ -e "$pristine" ]; then
echo "WARN: '$pristine' already exists. Skipping snapshot preparation." >&2
use_snapshot="no"
break
fi
done
if [ "$use_snapshot" = "yes" ]; then
echo "Migrating '$machine'"
for d in $disks; do
real=`readlink -f "$d"`
dir=`dirname "$real"`
bn=`basename "$real" .qcow2`
pristine="$dir/$bn.pristine.qcow2"
echo " updating disks to use '<driver name='qemu' type='qcow2' cache='writeback'/>"
update_disk_cache "$machine"
echo " moving '$real' to '$pristine'"
mv -f "$real" "$pristine"
done
performed_migration="yes"
else
errors="yes"
fi
echo ""
done
if [ "$performed_migration" = "yes" ]; then
using_snapshots
fi
if [ "$errors" = "yes" ]; then
exit 1
fi
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