ReaR with Borg back end to USB.

doc/user-guide/04-scenarios.adoc

@@ -78,8 +78,14 @@ TAPE_DEVICE=/dev/nst0
 ----
 
 
-== Bootable ISO with Borg
+== ReaR with Borg back end
  - Install Borg backup (https://borgbackup.readthedocs.io/en/stable/installation.html).
+
+IMPORTANT:  We strongly recommend to use Borg standalone binary (https://github.com/borgbackup/borg/releases) as it includes all necessities for Borg operations.
+			If you decide to go for different type of Borg installation types, make sure you include all needed files for Borg runtime into ReaR rescue/recovery system.
+			E.g. by using `COPY_AS_IS_BORG=( '/usr/lib64/python3.4*' '/usr/bin/python3*' '/usr/bin/pyvenv*' '/usr/lib/python3.4*' '/usr/lib64/libpython3*' )`
+
+=== Borg -> SSH
  - Setup ssh key infrastructure for user that will be running backup.
 Issuing following command must work without any password prompts or remote host identity confirmation:
 
@@ -117,6 +123,36 @@ export BORG_RELOCATED_REPO_ACCESS_IS_OK="yes"
 export BORG_UNKNOWN_UNENCRYPTED_REPO_ACCESS_IS_OK="yes"
 
 ----
+=== Borg -> USB
+
+ - Example _local.conf_:
+[source,bash]
+----
+OUTPUT=USB
+BACKUP=BORG
+
+USB_DEVICE=/dev/disk/by-label/REAR-000
+
+BORGBACKUP_REPO="/my_borg_backup"
+BORGBACKUP_UMASK="0002"
+
+BORGBACKUP_PRUNE_WEEKLY=2
+
+BORGBACKUP_ENC_TYPE="keyfile"
+export BORG_PASSPHRASE="S3cr37_P455w0rD"
+
+export BORG_RELOCATED_REPO_ACCESS_IS_OK="yes"
+export BORG_UNKNOWN_UNENCRYPTED_REPO_ACCESS_IS_OK="yes"
+
+COPY_AS_IS_EXCLUDE=( "${COPY_AS_IS_EXCLUDE[@]}" )
+COPY_AS_IS_BORG=( '/root/.config/borg/keys/' )
+
+SSH_UNPROTECTED_PRIVATE_KEYS="yes"
+SSH_FILES="yes"
+
+
+----
+
 IMPORTANT: If using BORGBACKUP_ENC_TYPE="keyfile", don't forget to make your
            encryption key available for case of restore!
            (using `COPY_AS_IS_BORG=( "/root/.config/borg/keys/" )` is a option to consider).
@@ -125,7 +161,7 @@ IMPORTANT: If using BORGBACKUP_ENC_TYPE="keyfile", don't forget to make your
 
  - Executing `rear mkbackup` will create Relax-and-Recover rescue/recovery system and
  start Borg backup process. Once backup finishes, it will also prune old archives from repository,
- if at least one of BORGBACKUP_PRUNE_* variables is set.
+ if at least one of `BORGBACKUP_PRUNE_*` variables is set.
  - To recover your system, boot Relax-and-Recover rescue/recovery system and trigger `rear recover`.
  You will be prompted which archive to recover from Borg repository, once ReaR finished with layout configuration.
 

usr/share/rear/backup/BORG/default/250_mount_usb.sh

@@ -0,0 +1,9 @@
+# This file is part of Relax-and-Recover, licensed under the GNU General
+# Public License. Refer to the included COPYING for full text of license.
+#
+# 250_mount_usb.sh
+
+# We need to mount USB destination device prior the backup starts
+if [[ -z $BORGBACKUP_HOST ]]; then
+    mount_url usb://$USB_DEVICE $borg_dst_dev
+fi

usr/share/rear/backup/BORG/default/500_make_backup.sh

@@ -16,18 +16,18 @@ for i in $(cat $TMP_DIR/backup-include.txt); do
     include_list+=("$i ")
 done
 
-Log "Creating archive ${BORGBACKUP_ARCHIVE_PREFIX}_$BORGBACKUP_SUFFIX \
-in repository $BORGBACKUP_REPO on host $BORGBACKUP_HOST"
-
 # Only in ReaR verbose mode also show borg progress output and stats
 local borg_progress=''
 test "$verbose" && borg_progress='--progress --stats'
 
 # Start actual Borg backup.
+Log "Creating archive ${BORGBACKUP_ARCHIVE_PREFIX}_$BORGBACKUP_SUFFIX \
+in repository $BORGBACKUP_REPO"
+
 borg create --one-file-system $borg_progress $verbose \
-$BORGBACKUP_OPT_COMPRESSION $BORGBACKUP_OPT_REMOTE_PATH $BORGBACKUP_OPT_UMASK \
---exclude-from $TMP_DIR/backup-exclude.txt \
-$BORGBACKUP_USERNAME@$BORGBACKUP_HOST:$BORGBACKUP_REPO::\
+$BORGBACKUP_OPT_COMPRESSION $BORGBACKUP_OPT_REMOTE_PATH \
+$BORGBACKUP_OPT_UMASK --exclude-from $TMP_DIR/backup-exclude.txt \
+${borg_dst_dev}${BORGBACKUP_REPO}::\
 ${BORGBACKUP_ARCHIVE_PREFIX}_$BORGBACKUP_SUFFIX \
 ${include_list[@]} 0<&6 1>&7 2>&8
 

usr/share/rear/backup/BORG/default/800_prune_old_backups.sh

@@ -6,11 +6,11 @@
 if [ ! -z $BORGBACKUP_OPT_PRUNE ]; then
     # Purge old archives according user settings.
     LogPrint "Purging old Borg archives in repository $BORGBACKUP_REPO"
-
     borg prune --list ${BORGBACKUP_OPT_PRUNE[@]} \
     $BORGBACKUP_OPT_REMOTE_PATH $BORGBACKUP_OPT_UMASK \
     --prefix ${BORGBACKUP_ARCHIVE_PREFIX}_ \
-    $BORGBACKUP_USERNAME@$BORGBACKUP_HOST:$BORGBACKUP_REPO
+    ${borg_dst_dev}${BORGBACKUP_REPO}
+
     StopIfError "Failed to purge old backups"
 else
     # Purge is not set.

usr/share/rear/backup/BORG/default/900_umount_usb.sh

@@ -0,0 +1 @@
+../../../prep/BORG/default/900_umount_usb.sh

usr/share/rear/lib/borg-functions.sh

@@ -58,9 +58,8 @@ function borg_set_vars {
 
 # Query Borg server for repository information
 # and store it to BORGBACKUP_ARCHIVE_CACHE.
-# This should avoid repeatingly quering Borg server, which could be slow.
+# This avoids repeatedly querying Borg repository, which could be slow.
 function borg_archive_cache_create {
-    borg list $BORGBACKUP_OPT_REMOTE_PATH \
-$BORGBACKUP_USERNAME@$BORGBACKUP_HOST:$BORGBACKUP_REPO \
+    borg list $BORGBACKUP_OPT_REMOTE_PATH ${borg_dst_dev}${BORGBACKUP_REPO} \
 2> /dev/null > $BORGBACKUP_ARCHIVE_CACHE
 }

usr/share/rear/prep/BORG/default/100_set_vars.sh

@@ -4,3 +4,17 @@
 # 100_set_vars.sh
 
 borg_set_vars
+
+# If BORGBACKUP_HOST is not set, we automatically assume that USB device should
+# be used as backup back end.
+# borg_dst_dev will be set to mount point, where USB_DEVICE will be mounted
+# in case of empty BORGBACKUP_HOST. While by non-zero BORGBACKUP_HOST we assume
+# that SSH should be used as transfer protocol and borg_dst_dev becomes
+# combined string of "BORGBACKUP_USERNAME@BORGBACKUP_HOST".
+# borg_dst_dev directory will be created in later stage
+# (if not already present) by 250_mount_usb.sh script.
+if [[ -n $BORGBACKUP_HOST ]]; then
+    borg_dst_dev=$BORGBACKUP_USERNAME@$BORGBACKUP_HOST:
+else
+    borg_dst_dev=$BUILD_DIR/borg_backup
+fi

usr/share/rear/prep/BORG/default/250_mount_usb.sh

@@ -0,0 +1,15 @@
+# This file is part of Relax-and-Recover, licensed under the GNU General
+# Public License. Refer to the included COPYING for full text of license.
+#
+# 250_mount_usb.sh
+
+# We need to mount USB_DEVICE in order to prepare for Borg archive
+# initialization, but only if BORGBACKUP_HOST is not set.
+# When BORGBACKUP_HOST is set, we don't need to mount anything as SSH
+# backup destination will be handled internally by Borg it self.
+if [[ -z $BORGBACKUP_HOST ]]; then
+    mkdir -p $v "$borg_dst_dev" >&2
+    StopIfError "Could not mkdir '$borg_dst_dev'"
+
+    mount_url usb://$USB_DEVICE $borg_dst_dev
+fi

usr/share/rear/prep/BORG/default/300_init_archive.sh

@@ -19,16 +19,16 @@ borg_archive_cache_create
 # will be skipped.
 rc=$?
 
-# This might be a Borg connection error, or missing repository.
+# This might be a Borg connection / mount error, or missing repository.
 # If initialization succeeds, we can rule out connection problems.
 # `borg init` has to be triggered in "prep" stage if user decides to include
 # keyfiles to Relax-and-Recover rescue/recovery system using COPY_AS_IS_BORG.
 if [ $rc -ne 0 ]; then
-    LogPrint "Failed to list $BORGBACKUP_REPO on $BORGBACKUP_HOST"
-    LogPrint "Creating new Borg repository $BORGBACKUP_REPO on $BORGBACKUP_HOST"
+    LogPrint "Failed to list $BORGBACKUP_REPO"
+    LogPrint "Creating new Borg repository $BORGBACKUP_REPO"
+
     borg init $BORGBACKUP_OPT_ENCRYPTION $BORGBACKUP_OPT_REMOTE_PATH \
-    $BORGBACKUP_OPT_UMASK \
-    $BORGBACKUP_USERNAME@$BORGBACKUP_HOST:$BORGBACKUP_REPO
+    $BORGBACKUP_OPT_UMASK ${borg_dst_dev}${BORGBACKUP_REPO}
     rc=$?
 fi
 

usr/share/rear/prep/BORG/default/900_umount_usb.sh

@@ -0,0 +1,10 @@
+# This file is part of Relax-and-Recover, licensed under the GNU General
+# Public License. Refer to the included COPYING for full text of license.
+#
+# 900_umount_usb.sh
+
+# After BORG operations are over, we can finally umount USB_DEVICE.
+# This will force final sync of data that can still sit in cache.
+if [[ -z $BORGBACKUP_HOST ]]; then
+    umount_url usb://$USB_DEVICE $borg_dst_dev
+fi

usr/share/rear/restore/BORG/default/250_mount_usb.sh

@@ -0,0 +1 @@
+../../../prep/BORG/default/250_mount_usb.sh

usr/share/rear/restore/BORG/default/400_restore_backup.sh

@@ -14,10 +14,11 @@ StopIfError "Could not change directory to $TARGET_FS_ROOT"
 # and should not interfere with remaining stages of rear recover.
 # This is still not the ideal solution, but best I can think of so far :-/.
 LogPrint "Recovering from Borg archive $BORGBACKUP_ARCHIVE"
+
 LC_ALL=rear.UTF-8 \
 borg extract --sparse $BORGBACKUP_OPT_REMOTE_PATH \
-$BORGBACKUP_USERNAME@$BORGBACKUP_HOST:$BORGBACKUP_REPO::$BORGBACKUP_ARCHIVE
-StopIfError "Could not successfully finish Borg restore"
+${borg_dst_dev}${BORGBACKUP_REPO}::$BORGBACKUP_ARCHIVE
 
+LogPrintIfError "Error was reported during Borg restore"
 LogPrint "Borg OS restore finished successfully"
 popd >/dev/null