Backup scripts read device/UUID/target from the host config

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

failover/sync-sd-backup.sh

@@ -19,9 +19,14 @@
 # The bootloader in the SD's first sectors (idbloader/u-boot) is not touched.
 set -euo pipefail
 
+# Backup settings come from the host config (see hosts/vanlink.conf.example).
+# shellcheck disable=SC1090
+. "${VANLINK_CONF:-/etc/vanlink.conf}"
+: "${SD_BACKUP_UUID:?set SD_BACKUP_UUID in /etc/vanlink.conf}"
+
 [ "$(id -u)" -eq 0 ] || { echo "Run as root (sudo)." >&2; exit 1; }
 
-SD_UUID=39118305-4927-47a4-acc7-ba022f37af22
+SD_UUID=$SD_BACKUP_UUID
 SD_ROOT_PART=/dev/disk/by-uuid/$SD_UUID
 MOUNT_POINT=/mnt/sd-backup-root
 FAILSAFE='boot-failesafe-rename-to:boot.scr'

failover/sync-usb-backup.sh

@@ -11,15 +11,19 @@
 # memory "sd-fallback-fstab-clobber" for what breaks if those leak across.
 set -euo pipefail
 
+# Backup settings come from the host config (see hosts/vanlink.conf.example).
+# shellcheck disable=SC1090
+. "${VANLINK_CONF:-/etc/vanlink.conf}"
+: "${USB_BACKUP_ROOT_PART:?set USB_BACKUP_ROOT_PART in /etc/vanlink.conf}"
+: "${USB_BACKUP_MOUNT:?set USB_BACKUP_MOUNT in /etc/vanlink.conf}"
+
 [ "$(id -u)" -eq 0 ] || { echo "Run as root (sudo)." >&2; exit 1; }
 
-USB_ROOT_PART=/dev/sda2
-MOUNT_POINT=/mnt/usb-backup-root
-MOUNT_POINT=10.42.1.44:/media/andreas/writable-nvme
+USB_ROOT_PART=$USB_BACKUP_ROOT_PART
+MOUNT_POINT=$USB_BACKUP_MOUNT
 
-
-[[ "$MOUNT_POINT" == *":"* ]]
-LOCAL_MOUNT=$?
+# host:/path means an already-exported NFS target: nothing to mount locally.
+if [[ "$MOUNT_POINT" == *":"* ]]; then LOCAL_MOUNT=0; else LOCAL_MOUNT=1; fi
 
 root_src=$(findmnt -no SOURCE /)
 if [ "$root_src" = "$USB_ROOT_PART" ]; then