Fix missing overlayfs

diskless.pkr.hcl

@@ -194,8 +194,9 @@ build {
       # ---- Diskless adaptations ------------------------------------------
       # Per-host machine-id is generated at boot into the overlay
       "truncate -s 0 /etc/machine-id",
-      # Read-only NFS root; runtime state on tmpfs/overlay (rootovl via the
-      # dracut 'overlayfs' module is pulled in by 90-diskless.conf)
+      # Read-only erofs/verity root; runtime state on a tmpfs overlay provided
+      # by systemd.volatile=overlay (set in the cmdline by extract-artifacts.sh).
+      # RHEL/Rocky dracut has no 'overlayfs'/'rootovl' module.
       "printf '%s\\n' '# diskless: root is provided by netroot; no local mounts' > /etc/fstab",
       # No local bootloader regeneration wanted on kernel updates inside CI
       "command -v grub2-mkconfig >/dev/null && echo 'GRUB updates not used on diskless hosts' || true",