Many of you may have had some trouble with getting virsh working with external snapshots. This is rather problematic, in that you can't get uefi images to easily be 'saved' without doing a lot of crap. this is one of the best resources I have found for doing this. I am saving this in case the original page goes away.
virsh-snap.sh: create and revert external libvirt snapshots easily
Installation
Download script:
wget -P ~/.local/bin https://github.com/shvchk/virsh-external-snapshots/raw/main/virsh-snap.shMake it executable:
chmod +x ~``/.local/bin/virsh-snap.sh
Usage
Create snapshot named snapshot-1 of vm-42:
virsh-snap.sh create vm-42 snapshot-1
Snapshot name is optional, by default current date and time is used as a name, e.g. 2022.07.29_23.55.12.
List snapshots of vm-42:
virsh-snap.sh list vm-42Note that this is not the same as virsh snapshot-list. Snapshots are created without metadata and won't be shown with virsh snapshot-list.
Revert and delete snapshot-1 of vm-42:
virsh-snap.sh revert vm-42 snapshot-1
Revert, but don't delete snapshot-1 of vm-42:
virsh-snap.sh soft-revert vm-42 snapshot-1
This allows to use this snapshot later with unrevert.
Undo revert of a snapshot-1 of vm-42, i.e. make it active again:
virsh-snap.sh unrevert vm-42 snapshot-1
Delete snapshot snapshot-1 of vm-42:
virsh-snap.sh delete vm-42 snapshot-1
Might be useful if you change your mind after soft-revert.
Show help:
virsh-snap.sh help
virsh-snap.sh: create and revert external libvirt snapshots easily
Usage: virsh-snap.sh <action> <domain> [snapshot name]
Actions:
--------
create, c Create snapshot
If no snapshot name is provided, current date and time is used
list, ls, l List snapshots
disks Show active disks
revert, rev, r Revert snapshot and delete it (same as soft-revert + delete)
soft-revert,
srev, sr Revert snapshot without deleting it (allows unrevert)
unrevert,
unrev, ur Unrevert snapshot, i.e. make soft-reverted snapshot active again
delete, del, rm Delete snapshot
help, h This message
Snapshots are created without metadata, so they won't be shown with `virsh snapshot-list`Below is the original script in case it disappears
#! /usr/bin/env bash
set -euo pipefail
conf_dir="${HOME}/.local/VM/snapshots"
prefix="_pre_"
_help() {
local script_name
script_name="$(basename -- "$0")"
printf "%s\n" \
"${script_name}: create and revert external libvirt snapshots easily" \
"" \
"Usage: $script_name <action> <domain> [snapshot name]" \
"" \
"" \
"Actions:" \
"--------" \
"create, c Create snapshot" \
" If no snapshot name is provided, current date and time is used" \
"" \
"list, ls, l List snapshots" \
"" \
"disks Show active disks" \
"" \
"revert, rev, r Revert snapshot and delete it (same as soft-revert + delete)" \
"" \
"soft-revert," \
"srev, sr Revert snapshot without deleting it (allows unrevert)" \
"" \
"unrevert," \
"unrev, ur Unrevert snapshot, i.e. make soft-reverted snapshot active again" \
"" \
"delete, del, rm Delete snapshot" \
"" \
"help, h This message" \
"" \
"" \
"Snapshots are created without metadata, so they won't be shown with \`virsh snapshot-list\`"
}
_die() {
echo "${1}. Exit."
exit 1
}
_yes_or_no() {
echo
local yn
while true; do
read -p "$* [ enter + or - ]: " yn < /dev/tty || _die "No tty"
case "$yn" in
"+") return 0 ;;
"-") return 1 ;;
esac
done
}
_die_on_auto_name() {
[ "$auto_name" = false ] || _die "No snapshot name provided"
}
_has_disks() {
virsh domblklist "$domain" --details | grep -qE 'file\s+disk' || return 1
}
_get_disks_path() {
virsh domblklist "$domain" --details | grep -E 'file\s+disk' | sed -E 's|[^/]+(.+)|\1|'
}
_create() {
_has_disks || _die "'${domain}' has no disks, nothing to snapshot"
local base_conf snap_conf
base_conf="${domain_conf_dir}/${prefix}${name}.xml"
snap_conf="${domain_conf_dir}/${name}.xml"
_get_disks_path | while IFS= read -r base_disk; do
local snap_disk
snap_disk="${base_disk%.*}.${name}" # expected
[ ! -e "$snap_disk" ] || _die "Disk '$snap_disk' already exist"
[ ! -e "$snap_conf" ] || _die "Snapshot conf '$snap_conf' already exist"
echo "Base disk: $base_disk"
echo "Overlay disk: $snap_disk"
done
virsh dumpxml "$domain" > "$base_conf"
virsh snapshot-create-as "$domain" "$name" --disk-only --no-metadata --atomic
virsh dumpxml "$domain" > "$snap_conf"
}
_list() {
local f
shopt -s nullglob
for f in "${domain_conf_dir}"/*.xml; do
f="$(basename -- "$f")"
[ "${f:0:5}" != "_pre_" ] || continue
echo "${f%.xml}";
done
shopt -u nullglob
}
_delete() {
_die_on_auto_name
# We could just rm $disk, but after revert it won't point to the right snapshot disk path,
# so we construct the right path manually
local snap_conf snap_parent_conf
snap_conf="${domain_conf_dir}/${name}.xml"
snap_parent_conf="${domain_conf_dir}/${prefix}${name}.xml"
_get_disks_path | while IFS= read -r disk; do
local snap_disk disk_dir sudo_cmd
snap_disk="${disk%.*}.${name}"
disk_dir="$(dirname -- "$disk")"
sudo_cmd=""
if [ "$disk" = "$snap_disk" ]; then
echo "Looks like you are deleting snapshot which is currently in use"
echo "You won't be able to revert if you delete it"
_yes_or_no "Are you sure?" || return
fi
if [ ! -w "$disk_dir" ] || [ ! -x "$disk_dir" ]; then
sudo_cmd="sudo"
echo "Root privileges required to remove disk file '$snap_disk'"
fi
[ -f "$snap_disk" ] && $sudo_cmd rm "$snap_disk"
done
[ -f "$snap_conf" ] && rm "$snap_conf"
[ -f "$snap_parent_conf" ] && rm "$snap_parent_conf"
}
_soft_revert() {
_die_on_auto_name
virsh define "${domain_conf_dir}/${prefix}${name}.xml"
}
_revert() {
_die_on_auto_name
_soft_revert
_delete
}
_unrevert() {
_die_on_auto_name
virsh define "${domain_conf_dir}/${name}.xml"
}
[ -n "${1:-}" ] || _die 'No action specified'
[ -n "${2:-}" ] || { _help; exit 1; }
action="$1"
domain="$2"
domain_conf_dir="${conf_dir}/${domain}"
[ -d "$domain_conf_dir" ] || mkdir -p "$domain_conf_dir"
if [ -n "${3:-}" ]; then
auto_name=false
name="$3"
else
auto_name=true
name="$(date +'%Y.%m.%d_%H.%M.%S')"
fi
case "$action" in
create|c)
_create
;;
list|ls|l)
_list
;;
disks)
_get_disks_path
;;
delete|del|rm)
_delete
;;
revert|rev|r)
_revert
;;
soft-revert|srev|sr)
_soft_revert
;;
unrevert|unrev|ur)
_unrevert
;;
help|h)
_help
;;
*)
_help
exit 1
;;
esac