73 lines
2.6 KiB
Bash
Executable File
73 lines
2.6 KiB
Bash
Executable File
#!/usr/bin/env bash
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# Refresh the USB disk (sda) as a live boot-fallback clone of the
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# running root filesystem. Run manually after a push:
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# sudo ./failover/sync-usb-backup.sh
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#
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# EEPROM BOOT_ORDER falls back to the SD card, then this USB disk, if the
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# primary boot disk (NVMe) doesn't come up. /etc/fstab, /etc/machine-id,
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# and /var/log are excluded from the sync so the clone keeps its own
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# partition identity (PARTUUIDs differ per disk) and boot/journal history
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# instead of inheriting the source disk's — see failover/README or repo
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# memory "sd-fallback-fstab-clobber" for what breaks if those leak across.
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set -euo pipefail
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# Backup settings come from the host config (see hosts/vanlink.conf.example).
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# shellcheck disable=SC1090
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. "${VANLINK_CONF:-/etc/vanlink.conf}"
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: "${USB_BACKUP_ROOT_PART:?set USB_BACKUP_ROOT_PART in /etc/vanlink.conf}"
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: "${USB_BACKUP_MOUNT:?set USB_BACKUP_MOUNT in /etc/vanlink.conf}"
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[ "$(id -u)" -eq 0 ] || { echo "Run as root (sudo)." >&2; exit 1; }
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USB_ROOT_PART=$USB_BACKUP_ROOT_PART
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MOUNT_POINT=$USB_BACKUP_MOUNT
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# host:/path means an already-exported NFS target: nothing to mount locally.
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if [[ "$MOUNT_POINT" == *":"* ]]; then LOCAL_MOUNT=0; else LOCAL_MOUNT=1; fi
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root_src=$(findmnt -no SOURCE /)
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if [ "$root_src" = "$USB_ROOT_PART" ]; then
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echo "Currently booted from $USB_ROOT_PART — refusing to sync USB onto itself." >&2
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exit 1
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fi
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if [ $LOCAL_MOUNT -eq 1 ]; then
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mkdir -p "$MOUNT_POINT"
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mounted_here=0
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if ! mountpoint -q "$MOUNT_POINT"; then
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mount "$USB_ROOT_PART" "$MOUNT_POINT"
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mounted_here=1
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else
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mount -o remount,rw "$MOUNT_POINT"
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fi
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cleanup() {
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if [ "$mounted_here" -eq 1 ]; then
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umount "$MOUNT_POINT"
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fi
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}
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trap cleanup EXIT
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fi
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# rsync exit 24 ("partial transfer due to vanished source files") is expected on a
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# live root — files like container shm sockets or in-progress logs routinely disappear
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# mid-sync. Tolerate that one code; anything else is a real failure and still aborts.
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rc=0
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rsync -aHAX --numeric-ids --delete \
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--info=progress2 \
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--exclude=/proc/* --exclude=/sys/* --exclude=/dev/* --exclude=/run/* \
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--exclude=/tmp/* --exclude=/mnt/* --exclude=/media/* --exclude=/lost+found \
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--exclude=/boot/firmware/* --exclude=/swapfile \
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--exclude=/etc/fstab --exclude=/etc/machine-id --exclude=/var/log/* \
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--stats / "$MOUNT_POINT/" || rc=$?
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if [ "$rc" -ne 0 ] && [ "$rc" -ne 24 ]; then
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echo "rsync failed (exit $rc)." >&2
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exit "$rc"
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fi
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if [ "$rc" -eq 24 ]; then
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echo "Note: some files vanished mid-sync (rsync exit 24) — normal on a live root." >&2
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fi
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echo "USB backup ($USB_ROOT_PART) synced from $root_src."
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