ACLs are not preserved restoring custom image

[geigerl]

Hi,
i created a backup bash script which tars specific directories and files - to basically have a restorable OS image.
After testing the backup-restore process, I realized my ACLs were no longer there.

Here is the tar command that is executed to build the image:

tar \
  --create \
  --gzip \
  --file "$LOCAL_TAR" \
  --directory "$TAR_ROOT" \
  --numeric-owner \
  --acls --xattrs \
  --one-file-system \
  "${TAR_EXCLUDES[@]}" \
  "${FILTERED_WHITELIST[@]/#/./}" \
  "${BOOT_TAR_ARGS[@]}" \
  "${BOOT_EFI_TAR_ARGS[@]}" \

OS: Ubuntu-2404 noble
ARCH: amd64
tar version: GNU tar 1.35
setfactl version: 2.3.2

The ACLs were created by setfacl (e.g. setfacl -m "u:${USER_ID}:${ACL_MODE}" "$PATH_TO_SET" or setfacl -R -m "u:${USER_ID}:${ACL_MODE}" "$PATH_TO_SET" or setfacl -R -d -m "u:${USER_ID}:${ACL_MODE}" "$PATH_TO_SET")

I used installimage with /autosetup containing (this config was used to create the system in the first place, before the backup restoration):

DRIVE1 /dev/nvme0n1
DRIVE2 /dev/nvme1n1

SWRAID 1
SWRAIDLEVEL 1

BOOTLOADER grub
USE_KERNEL_MODE_SETTING yes

HOSTNAME hetzner-ax42-prod-1

PART /boot/efi esp 256M
PART swap swap 31G
PART /boot ext3 1024M
PART /     btrfs all

IMAGE /root/Ubuntu-2404-noble-amd64-hetzner-ax42-prod-1-backup-2026-02-06_033002.tar.gz

Not sure whether the untaring in the installimage script does not set the --acls flag or there is another issue.
However, as ACLs are pain I decided to not use it anymore for my use cases but I wanted to share my finding.