James Coleman
25f11d5535
- Update copyright year to 2026 - Point BORG_REPO to remote backup host - Fix RBD pid file name to avoid collision with images backup - Fix snapshot count typo and off-by-one error in RBD cleanup - Add error handling for rbd snap create - Fix prune log messages to reference domain instead of image - Add new kvm-backup-zvol-iscsi.sh for ZVol over iSCSI backups
309 lines
10 KiB
Bash
309 lines
10 KiB
Bash
#!/bin/bash
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# Copyright (c) 2026 Mr. Gecko's Media (James Coleman). http://mrgeckosmedia.com/
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# This is for backing up ZFS zvol-backed VMs exported via iSCSI.
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# Runs on the ZFS server where the zvols live. VM domains are
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# discovered via virsh on remote libvirt hosts connected over iSCSI,
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# matching the domain-driven approach of the other kvm-backup scripts.
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# A file to prevent overlapping runs.
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PIDFILE="/tmp/backup-zvol-iscsi.pid"
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# If the pid file exists and process is running, exit.
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if [[ -f "$PIDFILE" ]]; then
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PID=$(cat "$PIDFILE")
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if ps -p "$PID" >/dev/null; then
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echo "Backup process already running, exiting."
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exit 1
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fi
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fi
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# Create a new pid file for this process.
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echo $BASHPID >"$PIDFILE"
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# The borg repository we're backing up to.
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export BORG_REPO='root@10.0.0.5:/media/Storage/Backup/kvm'
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# If you have a passphrase for your repository,
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# set it here or you can use bash to retrieve it.
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# export BORG_PASSPHRASE=''
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# Set answers for automation.
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export BORG_UNKNOWN_UNENCRYPTED_REPO_ACCESS_IS_OK=yes
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export BORG_RELOCATED_REPO_ACCESS_IS_OK=yes
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export BORG_CHECK_I_KNOW_WHAT_I_AM_DOING=NO
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export BORG_DELETE_I_KNOW_WHAT_I_AM_DOING=NO
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# Set to empty string to disable pruning.
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PRUNE_OPTIONS="--keep-daily 7 --keep-weekly 4 --keep-monthly 6"
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# Number of ZFS snapshots to keep per zvol.
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SNAPSHOTS_KEEP=2
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# The parent ZFS dataset containing zvols to back up.
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ZFS_PARENT="tank/kvm"
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# Remote libvirt hosts for VM discovery and XML backup via SSH.
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# Each entry is an SSH destination (e.g. "root@hostname").
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# The script will run virsh list and domblklist on each host to
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# discover VMs with iSCSI-attached zvols, then back up the
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# corresponding local zvols.
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REMOTE_HOSTS=("root@kiki" "root@gaming-pc")
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# Whether to also discover and backup VMs from local libvirt.
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BACKUP_LOCAL=true
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# Remove PID file on exit.
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cleanup() {
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rm "$PIDFILE"
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}
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trap cleanup EXIT
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# Name the snapshot today's date.
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SNAPSHOT_NAME=$(date '+%Y-%m-%dT%H-%M-%S')
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# Allows providing an argument of a domain to specifically backup.
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BACKUP_DOMAIN="$1"
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# Failures should remove pid file and exit with status code 1.
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fail() {
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echo "$1"
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exit 1
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}
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# Cleanup old ZFS snapshots, keeping SNAPSHOTS_KEEP most recent.
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cleanupSnapshots() {
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ZVOL="$1"
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snapshots=()
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# Read list of snapshots for the provided zvol.
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SNAPLIST_STATUS_TMP="/tmp/backup-zvol-snap-tmp"
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while read -r NAME; do
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[[ -z "$NAME" ]] && continue
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snapshots+=("$NAME")
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done < <(
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zfs list -t snapshot -o name -s creation -H -r "$ZVOL" 2>/dev/null
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echo "${PIPESTATUS[0]}" >"$SNAPLIST_STATUS_TMP"
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)
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# Get status from the snapshot listing.
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status=1
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if [[ -f $SNAPLIST_STATUS_TMP ]]; then
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status=$(cat "$SNAPLIST_STATUS_TMP")
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rm "$SNAPLIST_STATUS_TMP"
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fi
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# If status has an error, exit.
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if ((status!=0)); then
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fail "Snapshot listing failed for $ZVOL"
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fi
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# If the snapshot count is more than the number to keep,
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# remove snapshots until count matches.
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# The snapshots are listed from oldest to newest, so this
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# should keep the newer snapshots.
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snapshot_count=${#snapshots[@]}
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if ((snapshot_count>SNAPSHOTS_KEEP)); then
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for ((i = 0; snapshot_count-i > SNAPSHOTS_KEEP; i++)); do
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NAME=${snapshots[$i]}
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echo "Removing snapshot: $NAME"
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zfs destroy "$NAME"
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done
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fi
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}
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# Extract the zvol name from an iSCSI by-path device path.
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# Example input: /dev/disk/by-path/ip-10.0.100.6:3260-iscsi-iqn.2026-03.im.gec.host:MainServer-lun-0
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# Example output: MainServer
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# The zvol name is the target name portion of the IQN (after the last colon,
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# before the -lun- suffix).
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extractZvolName() {
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local PATH_STR="$1"
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# Strip everything up to "-iscsi-" to get the IQN and lun.
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local IQN="${PATH_STR##*-iscsi-}"
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# Strip the "-lun-*" suffix.
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IQN="${IQN%-lun-*}"
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# The target name is after the last colon.
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echo "${IQN##*:}"
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}
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# Back up domains from a virsh source.
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# Usage: backupDomains "ssh_prefix" "host_label"
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# ssh_prefix: empty string for local virsh, or "ssh user@host" for remote.
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# host_label: label for log messages and archive naming (e.g. "local", "kiki").
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backupDomains() {
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local SSH_PREFIX="$1"
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local HOST_LABEL="$2"
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DOMLIST_STATUS_TMP="/tmp/backup-zvol-domlist-$HOST_LABEL-tmp"
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while read -r _ DOMAIN _; do
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# If the domain is empty, skip.
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if [[ -z "$DOMAIN" ]]; then
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continue
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fi
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# If a backup domain was provided, only backup that domain.
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if [[ -n "$BACKUP_DOMAIN" ]] && [[ "$BACKUP_DOMAIN" != "$DOMAIN" ]]; then
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continue
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fi
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# Get the block devices for this domain.
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DEVS=()
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ZVOL_NAMES=()
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BLKLIST_STATUS_TMP="/tmp/backup-zvol-blklist-$HOST_LABEL-tmp"
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while read -r DEV IMAGE; do
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# Ignore empty line or no image.
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if [[ -z "$IMAGE" ]] || [[ "$IMAGE" == "-" ]]; then
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continue
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fi
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# Only process iSCSI by-path devices.
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if ! [[ "$IMAGE" =~ -iscsi- ]]; then
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continue
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fi
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# Extract the zvol name from the iSCSI path.
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ZVOL_NAME=$(extractZvolName "$IMAGE")
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if [[ -z "$ZVOL_NAME" ]]; then
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echo "Warning: Could not extract zvol name from $IMAGE, skipping"
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continue
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fi
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# Verify the zvol exists locally.
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ZVOL="$ZFS_PARENT/$ZVOL_NAME"
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if ! zfs list "$ZVOL" &>/dev/null; then
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echo "Warning: zvol $ZVOL does not exist locally, skipping"
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continue
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fi
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DEVS+=("$DEV")
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ZVOL_NAMES+=("$ZVOL_NAME")
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done < <(
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if [[ -n "$SSH_PREFIX" ]]; then
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$SSH_PREFIX "virsh domblklist '$DOMAIN'" 2>/dev/null | tail -n +3
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else
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virsh domblklist "$DOMAIN" | tail -n +3
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fi
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echo "${PIPESTATUS[0]}" >"$BLKLIST_STATUS_TMP"
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)
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# Get status from the block listing.
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status=1
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if [[ -f $BLKLIST_STATUS_TMP ]]; then
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status=$(cat "$BLKLIST_STATUS_TMP")
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rm "$BLKLIST_STATUS_TMP"
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fi
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# If status has an error, exit.
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if ((status!=0)); then
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fail "Domain block listing failed for $DOMAIN ($HOST_LABEL)"
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fi
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# For each iSCSI disk, snapshot the zvol and back it up.
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for ((i = 0; i < ${#DEVS[@]}; i++)); do
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DEV=${DEVS[$i]}
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ZVOL_NAME=${ZVOL_NAMES[$i]}
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ZVOL="$ZFS_PARENT/$ZVOL_NAME"
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# Create a ZFS snapshot.
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echo "Creating snapshot: $ZVOL@$SNAPSHOT_NAME"
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if ! zfs snapshot "$ZVOL@$SNAPSHOT_NAME"; then
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fail "Failed to create snapshot for $ZVOL"
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fi
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# Read the raw disk image from the snapshot's block device.
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# This produces a portable raw image that can be restored to
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# any virtual disk or converted with qemu-img, without
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# requiring ZFS on the restore target.
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SNAP_DEV="/dev/zvol/$ZVOL@$SNAPSHOT_NAME"
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echo "Creating backup for $DOMAIN ($DEV [$ZVOL])"
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if ! dd if="$SNAP_DEV" bs=4M status=none | pv | borg create \
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--verbose \
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--stats \
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--show-rc \
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"::$DOMAIN-$DEV-{now}" -; then
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fail "Failed to backup $DOMAIN ($DEV)"
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fi
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# Prune if options are configured.
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if [[ -n "$PRUNE_OPTIONS" ]]; then
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echo "Pruning backups for $DOMAIN ($DEV)"
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if ! eval borg prune --list \
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--show-rc \
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--glob-archives "'$DOMAIN-$DEV-*'" \
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"$PRUNE_OPTIONS"; then
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fail "Failed to prune $DOMAIN ($DEV)"
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fi
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fi
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# Cleanup old ZFS snapshots.
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cleanupSnapshots "$ZVOL"
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done
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# Backup the domain XML.
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echo "Backing up $DOMAIN xml ($HOST_LABEL)"
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if [[ -n "$SSH_PREFIX" ]]; then
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if ! $SSH_PREFIX "virsh dumpxml '$DOMAIN'" 2>/dev/null | borg create \
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--verbose \
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--stats \
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--show-rc \
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"::$DOMAIN-xml-{now}" -; then
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fail "Failed to backup $DOMAIN xml"
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fi
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else
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if ! virsh dumpxml "$DOMAIN" | borg create \
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--verbose \
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--stats \
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--show-rc \
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"::$DOMAIN-xml-{now}" -; then
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fail "Failed to backup $DOMAIN xml"
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fi
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fi
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# Prune if options are configured.
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if [[ -n "$PRUNE_OPTIONS" ]]; then
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echo "Pruning xml backups for $DOMAIN"
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if ! eval borg prune --list \
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--show-rc \
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--glob-archives "'$DOMAIN-xml-*'" \
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"$PRUNE_OPTIONS"; then
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fail "Failed to prune $DOMAIN xml"
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fi
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fi
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done < <(
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if [[ -n "$SSH_PREFIX" ]]; then
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$SSH_PREFIX "virsh list --all" 2>/dev/null | tail -n +3
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else
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virsh list --all | tail -n +3
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fi
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echo "${PIPESTATUS[0]}" >"$DOMLIST_STATUS_TMP"
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)
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# Get status from the domain listing.
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status=1
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if [[ -f $DOMLIST_STATUS_TMP ]]; then
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status=$(cat "$DOMLIST_STATUS_TMP")
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rm "$DOMLIST_STATUS_TMP"
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fi
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# If status has an error, exit.
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if ((status!=0)); then
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if [[ -n "$SSH_PREFIX" ]]; then
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echo "Warning: Domain listing from $HOST_LABEL failed (host may be unreachable)"
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else
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fail "Local domain listing failed"
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fi
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fi
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}
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# Backup domains from local libvirt.
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if [[ "$BACKUP_LOCAL" == true ]]; then
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backupDomains "" "local"
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fi
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# Backup domains from remote libvirt hosts.
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for REMOTE_HOST in "${REMOTE_HOSTS[@]}"; do
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REMOTE_NAME="${REMOTE_HOST##*@}"
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backupDomains "ssh $REMOTE_HOST" "$REMOTE_NAME"
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done
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# Shrink repo.
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borg compact
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