[PATCH] testbot/BackupVM: A script for backing up a Libvirt/QEmu VM.
The script supports backing up to either a borg repository, possibly remote, the deduplication makes this ideal for backups; or tar files, which is more suited for archival. By default the script will refuse to perform the backup if it foundi no snapshots. If that's expected pass the --no-snapshot option. Signed-off-by: Francois Gouget <fgouget(a)codeweavers.com> --- testbot/scripts/BackupVM | 362 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 362 insertions(+) create mode 100755 testbot/scripts/BackupVM diff --git a/testbot/scripts/BackupVM b/testbot/scripts/BackupVM new file mode 100755 index 00000000..2cf3320d --- /dev/null +++ b/testbot/scripts/BackupVM @@ -0,0 +1,362 @@ +#!/bin/sh +# +# Creates a backup of a QEMU/LibVirt VM. +# +# Copyright 2013-2019 Francois Gouget +# +# This library is free software; you can redistribute it and/or +# modify it under the terms of the GNU Lesser General Public +# License as published by the Free Software Foundation; either +# version 2.1 of the License, or (at your option) any later version. +# +# This library is distributed in the hope that it will be useful, +# but WITHOUT ANY WARRANTY; without even the implied warranty of +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU +# Lesser General Public License for more details. +# +# You should have received a copy of the GNU Lesser General Public +# License along with this library; if not, write to the Free Software +# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA + +name0=`basename "$0"` + +etcdir="etc/libvirt/qemu" +snapdir="var/lib/libvirt/qemu/snapshot" + + +# +# Generic helpers +# + +error() +{ + echo "$name0:error:" "$@" >&2 +} + +warning() +{ + echo "$name0:warning:" "$@" >&2 +} + +opt_dry_run="" +opt_verbose="" +dry_run() +{ + [ -n "$opt_verbose$opt_dry_run" ] && echo "$@" + if [ -z "$opt_dry_run" ] + then + "$@" + fi +} + + +# +# Process the command line +# + +check_opt_val() +{ + option="$1" + var="$2" + argc="$3" + + if [ -n "$var" ] + then + error "$option can only be specified once" + usage=2 # but continue processing options + fi + if [ $argc -eq 0 ] + then + error "missing value for $option" + usage=2 + return 1 + fi + return 0 +} + +opt_vm="" +opt_suffix="" +opt_snapshot="1" +opt_borg="" +opt_connect="" +usage="" +while [ $# -gt 0 ] +do + arg="$1" + shift + case "$arg" in + --borg) + if check_opt_val "$arg" "$opt_borg" $# + then + opt_borg="$1" + shift + fi + ;; + --snapshot) + opt_snapshot="1" + ;; + --no-snapshot) + opt_snapshot="" + ;; + --connect) + if check_opt_val "$arg" "$opt_connect" $# + then + opt_connect="$1" + shift + fi + ;; + --verbose) + opt_verbose="1" + ;; + --dry-run) + opt_dry_run="1" + ;; + -\?|-h|--help) + usage=0 + ;; + -*) + error "unknown option '$arg'" + usage=2 + break + ;; + *) + if [ -z "$opt_vm" ] + then + opt_vm="$arg" + elif [ -z "$opt_suffix" ] + then + opt_suffix="$arg" + else + error "only one VM and suffix can be specified." + usage=2 + fi + ;; + esac +done + +if [ -z "$usage" ] +then + if [ -z "$opt_vm" ] + then + error "you must specify the name of the VM to backup." + usage=2 + fi + [ -n "$opt_connect" ] || opt_connect="qemu:///system" +fi + +if [ -n "$usage" ] +then + if [ "$usage" != "0" ] + then + error "try '$name0 --help' for more information" + exit $usage + fi + cat <<EOF +Usage: $name0 [--no-snapshot] [--verbose] [--dry-run] [--help] [--borg REPO] + [--connect URI] VMNAME [SUFFIX] + +Creates a backup of the specified VM. +This must be run as root on the VM host. + +Where: + VMNAME The name of the VM to backup. + SUFFIX A (short) string to add to the backup name. This can help + provide an indication of what features were added to this + backup. + --borg REPO The borg repository to backup to. + --no-snapshot It is ok for the VM to have no snapshot. + --connect URI Connect to the specified Libvirt server. + --verbose Show all the commands as they are being run. + --dry-run Show what would happen but do not extract or change anything. + --help, -h Shows this help message. +EOF + exit 0 +fi + + +# +# Prepare the backup +# + +get_vm_disk_images() +{ + _root="$1" + _vm="$2" + sed -e "s~^ *<source file='\([^']*\)' */> *\$~\\1~" -e t -e d "$_root$etcdir/$_vm.xml" "$_root$snapdir/$_vm"/*.xml | sort | uniq +} + +get_symlink_closure() +{ + while read file + do + echo "$file" + while [ -h "$file" ] + do + target=`readlink "$file"` + case "$target" in + /*) file="$target" ;; + *) file=`dirname "$file"`"/$target" ;; + esac + echo "$file" + done + done +} + +if [ ! -r "/$etcdir/$opt_vm.xml" ] +then + error "the '/$etcdir/$opt_vm.xml' configuration file is not readable" + exit 2 +fi + +snapshots=`echo "/$snapdir/$opt_vm"/*.xml` +if [ -n "$opt_snapshot" -a "$snapshots" = "/$snapdir/$opt_vm/*.xml" ] +then + error "the '$opt_vm' VM does not seem to have snapshots! Use --no-snapshot if this is expected." + exit 2 +fi + +# Backup the symbolic links but also their targets! +disks=`get_vm_disk_images "/" "$opt_vm" 2>/dev/null | get_symlink_closure | sort | uniq` +if [ -z "$disks" ] +then + error "could not find the disk images." + exit 2 +fi + +confs=`for file in "/$etcdir/$opt_vm.xml" $snapshots; do echo $file; done | get_symlink_closure` + +errors="" +all_paths="" +echo "$opt_vm uses the following files and directories:" +for file in $confs $disks +do + all_paths="$all_paths $file" + echo " $file" + if [ ! -r "$file" ] + then + error "'$file' is not readable." + errors=1 + fi +done +[ -z "$errors" ] || exit 1 +echo + + +# +# Wait for the VM +# + +fatal() +{ + error "$@" + exit 1 +} + +wait_for_vm() +{ + _vm="$1" + _timeout="$2" + + while true + do + _state=`(virsh --connect "$opt_connect" list --all 2>/dev/null || echo " $_vm error") | sed -e "s/^.* $_vm *//" -e t -e d` + [ -z "$opt_dry_run" ] || _state="shut off" + case "$_state" in + "error") + echo "nolibvirt" + return + ;; + "") + echo "novm" + return + ;; + "shut off") + echo "off" + return + ;; + esac + + echo "$_vm is not powered off ($_state). Waiting for up to ${_timeout}s..." >&2 + _timeout=`expr $_timeout - 10` + if [ $_timeout -le 0 ] + then + echo "running" + return + fi + sleep 10 + done +} + +# Note that we don't actually care whether libvirt knows about the VM since +# we know which files to backup anyway. +case `wait_for_vm "$opt_vm" 120` in +nolibvirt) + warning "Could not connect to libvirt. Assuming $opt_vm is not running." + ;; +running) + fatal "$opt_vm is running. Try again when it has been powered off." + ;; +esac + + +# +# Do the backup +# + +nice="" +which ionice >/dev/null && nice="ionice" +which nice >/dev/null && nice="nice $nice" + +backup="libvirt-$opt_vm-`date +%Y%m%d`" +[ -n "$opt_suffix" ] && backup="$backup-$opt_suffix" + +if [ -n "$opt_borg" ] +then + borg_opts="" + [ -n "$opt_verbose" ] && borg_opts="$borg_opts --verbose" + dry_run $nice borg create --progress --stats -C lzma,9 \ + "$opt_borg::$backup" $all_paths + rc_borg=$? + if [ $rc_borg -ne 0 ] + then + fatal "an error occurred while saving the VM (borg=$rc_borg)" + fi + echo "Saved $opt_vm to '$opt_borg::$backup'" + +else + zipcmd=pbzip2 + which pbzip2 >/dev/null || zipcmd=bzip2 + + tar_opts="" + [ -n "$opt_verbose" ] && tar_opts="-v" + if [ -n "$opt_verbose$opt_dry_run" ] + then + echo "$nice tar cf - $tar_opts $all_paths | $nice $zipcmd -9 | $nice split -d -b 2146435072 - '$backup.tar.bz2.'" + fi + + if [ -n "$opt_dry_run" ] + then + rc_tar=0 + rc_zip=0 + rc_split=0 + else + ($nice tar cf - $tar_opts $all_paths; echo $? >"rc_tar" ) | \ + ($nice $zipcmd -9; echo $? >"rc_zip") | \ + $nice split -d -b 2146435072 - "$backup.tar.bz2." + rc_split=$? + rc_zip=`cat "rc_zip"` + rc_tar=`cat "rc_tar"` + rm -f "rc_tar" "rc_zip" + fi + if [ "$rc_tar" != "0" -o "$rc_zip" != "0" -o "$rc_split" != "0" ] + then + fatal "an error occurred while saving the VM (tar=$rc_tar zip=$rc_zip split=$rc_split)" + fi + echo "Saved $opt_vm to '$backup.tar.bz2.*'" +fi + +case `wait_for_vm "$opt_vm" 0` in +running) + fatal "$opt_vm is running. The backup may be bad." + ;; +esac -- 2.20.1
participants (1)
-
Francois Gouget