From 539bdf9833a01e372bdcb4ff99bf7f6c50787336 Mon Sep 17 00:00:00 2001
From: beatzaplenty <wayne.bennett@live.com>
Date: Wed, 29 Jul 2026 13:58:53 +1000
Subject: [PATCH] fix(ha): resolve data disk device via by-id symlink even in
 dry-run
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The by-id lookup is read-only so it's safe to run in dry-run mode.
Previously it was gated behind `if ! $DRY_RUN`, which always triggered
the sdb fallback warning in dry-run — making it look like the device
path wasn't reliable when the symlink actually exists on both servers.

Now the lookup always runs and the script errors out with a clear message
if the by-id symlink is genuinely missing, instead of silently falling
back to a guessed /dev/sd* name.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
---
 scripts/ha/resize-data-disk.sh | 14 +++++---------
 1 file changed, 5 insertions(+), 9 deletions(-)

diff --git a/scripts/ha/resize-data-disk.sh b/scripts/ha/resize-data-disk.sh
index 4379cd9..13e6dc1 100755
--- a/scripts/ha/resize-data-disk.sh
+++ b/scripts/ha/resize-data-disk.sh
@@ -204,17 +204,13 @@ rescan_node() {
   local node_name=$1 run_fn=$2
 
   # Resolve block device name from the stable by-id symlink on the guest.
+  # Read-only lookup — safe to run even in dry-run so we show the real device.
   local blk_dev=""
-  if ! $DRY_RUN; then
-    blk_dev=$($run_fn "bash -c 'basename \$(readlink -f /dev/disk/by-id/${DATA_DISK_BYID})'" 2>/dev/null || true)
-  fi
+  blk_dev=$($run_fn "bash -c 'basename \$(readlink -f /dev/disk/by-id/${DATA_DISK_BYID})'" 2>/dev/null || true)
   if [[ -z "$blk_dev" ]]; then
-    # Fall back: scsi1 → index 1 → sdb, scsi2 → sdc, etc.
-    local slot_idx
-    slot_idx=$(echo "$DATA_DISK_SLOT" | grep -oE '[0-9]+$' || echo "1")
-    blk_dev=$(printf "sd%s" "$(echo "abcdefghij" | cut -c$((slot_idx + 1)))")
-    echo "  WARNING: could not resolve /dev/disk/by-id/${DATA_DISK_BYID} on $node_name;" \
-         "falling back to /dev/${blk_dev}" >&2
+    echo "  ERROR: /dev/disk/by-id/${DATA_DISK_BYID} not found on $node_name" >&2
+    echo "         Check DATA_DISK_BYID or DATA_DISK_SLOT configuration." >&2
+    exit 1
   fi
 
   echo "  ${DRY_PREFIX}Rescanning /dev/${blk_dev} on ${node_name}..."