Files
Workstation/ansible/arch_backup/templates/btrfs_backup.sh.j2
ducoterra 8abfbcf561 Fix issues where cryptsetup would fail to unmount
There were occasions where removing the backup drive would confuse luks
and prevent re-mounting. This fixes the issue by attempting to luks
close and open the drive before mounting, thereby correcting any issues
where the drive would stick.
2022-02-01 20:25:26 -05:00

102 lines
3.8 KiB
Django/Jinja
Executable File

#!/bin/bash
# Backup info
export BACKUP_DRIVE_UUID={{ disk.uuid }}
export BACKUP_DRIVE={{ disk.name }}
export BACKUP_DRIVE_PASSWORD={{ disk.password }}
# For notifications
export DBUS_SESSION_BUS_ADDRESS=unix:path=/run/user/{{ notifications.user.uid }}/bus
export USER={{ notifications.user.name }}
export SOURCE_DIR=${SOURCE_DIR:=/}
# Fix basename / showing up as "/" -> change to "root"
if [ $(basename $SOURCE_DIR) = / ]; then
export SNAPSHOT_PREFIX=${SNAPSHOT_PREFIX:=root}
else
export SNAPSHOT_PREFIX=${SNAPSHOT_PREFIX:=$(basename $SOURCE_DIR)}
fi
# Set snapshot prefix based on basename
export SNAPSHOT_TIME=$(date +"%y_%m_%d-%H.%M")
export SNAPSHOT_NAME=$SNAPSHOT_PREFIX-$SNAPSHOT_TIME
export SNAPSHOT_DIR=${SNAPSHOT_DIR:=/.snapshots}
export LATEST=$SNAPSHOT_PREFIX-latest
export BACKUP_DRIVE=backup0
export BACKUP_DRIVE_MNT=${BACKUP_DRIVE_MNT:=/mnt/$BACKUP_DRIVE}
export BACKUP_DIR=${BACKUP_DIR:=/mnt/$BACKUP_DRIVE/$(hostname)}
# Show snapshot settings
echo "SOURCE_DIR: $SOURCE_DIR"
echo "SNAPSHOT_PREFIX: $SNAPSHOT_PREFIX"
echo "SNAPSHOT_TIME: $SNAPSHOT_TIME"
echo "SNAPSHOT_NAME: $SNAPSHOT_NAME"
echo "SNAPSHOT_DIR: $SNAPSHOT_DIR"
echo "LATEST: $LATEST"
echo "BACKUP_DRIVE_MNT: $BACKUP_DRIVE_MNT"
echo "BACKUP_DIR: $BACKUP_DIR"
# Create readonly snapshot
btrfs subvolume snapshot -r $SOURCE_DIR $SNAPSHOT_DIR/$SNAPSHOT_NAME
# Attempt to mount backup disk
# Check if backup disk is mounted
mountpoint $BACKUP_DRIVE_MNT
if [ $? != 0 ]; then
cryptsetup luksClose $BACKUP_DRIVE
cryptsetup luksOpen /dev/disk/by-uuid/$BACKUP_DRIVE_UUID $BACKUP_DRIVE --key-file=$BACKUP_DRIVE_PASSWORD
mount $BACKUP_DRIVE_MNT
fi
# Check if backup disk is mounted
mountpoint $BACKUP_DRIVE_MNT
if [ $? = 0 ]; then # backup drive mounted
if [ ! -d $BACKUP_DIR ]; then
mkdir -p $BACKUP_DIR
fi
# Sync latest backups
# The "latest" symlinks can get out of sync for a variety of reasons,
# including backups run while the disk is unplugged.
# They must be kept in sync so that snapshots are sent with a parent
# that actually exists on the backup drive
#
# In order to keep them in sync we'll do the following:
# 1. Check the <backup>-latest on the backup drive matches
# <backup>-latest in the snapshot directory
# 2. If they don't match, assume the backup drive has the correct
# snapshot. Replace the <backup>-latest symlink in the snapshots
# directory with the one from the backup drive
#
# First check if the symlinks exist
if [ -L $SNAPSHOT_DIR/$LATEST ] && [ -L $BACKUP_DIR/$LATEST ]; then
# Get the actual name of the latest backup
LATEST_SNAPSHOT=$(basename $(readlink $SNAPSHOT_DIR/$LATEST))
LATEST_BACKUP=$(basename $(readlink $BACKUP_DIR/$LATEST))
# If the latest backups don't match
if [ $LATEST_SNAPSHOT != $LATEST_BACKUP ]
then
echo "Detected drift. Synchronizing latest snapshot with backup. Set to $LATEST_BACKUP."
# Remove and replace the snapshot directory's latest
rm $SNAPSHOT_DIR/$LATEST
ln -s $SNAPSHOT_DIR/$LATEST_BACKUP $SNAPSHOT_DIR/$LATEST
fi
fi
# If we have a latest, use it as the parent
if [ -L $BACKUP_DIR/$LATEST ]; then
btrfs send -p $SNAPSHOT_DIR/$LATEST $SNAPSHOT_DIR/$SNAPSHOT_NAME | btrfs receive $BACKUP_DIR
else
btrfs send $SNAPSHOT_DIR/$SNAPSHOT_NAME | btrfs receive $BACKUP_DIR
fi
# Update latest in backup dir
rm -f $BACKUP_DIR/$LATEST
ln -s $BACKUP_DIR/$SNAPSHOT_NAME $BACKUP_DIR/$LATEST
sudo -E -u $USER notify-send "Backup complete" "Snapshot $SNAPSHOT_NAME completed successfully"
else
sudo -E -u $USER notify-send "Backup failed" "$BACKUP_DRIVE_MNT not mounted. Snapshot $SNAPSHOT_NAME not synced" -u critical
fi
# Update latest in snapshot dir
rm -f $SNAPSHOT_DIR/$LATEST
ln -s $SNAPSHOT_DIR/$SNAPSHOT_NAME $SNAPSHOT_DIR/$LATEST