`enroot import` inside docker

[activatedgeek]

Is it possible to import docker images via enroot inside docker itself?

I have this Dockerfile,

ARG ENROOT_VERSION=4.0.1

FROM ubuntu:24.04

ENV DEBIAN_FRONTEND=noninteractive

RUN apt update -y && \
    apt install -y \
        bsdmainutils \
        curl \
        jq \
        libcap2-bin \
        parallel \
        squashfs-tools \
        zstd && \
    rm -rf /var/lib/apt/lists/*

ARG ENROOT_VERSION
RUN arch=$(dpkg --print-architecture) && \
    curl -fSsL -O https://github.com/NVIDIA/enroot/releases/download/v${ENROOT_VERSION}/enroot_${ENROOT_VERSION}-1_${arch}.deb && \
    curl -fSsL -O https://github.com/NVIDIA/enroot/releases/download/v${ENROOT_VERSION}/enroot+caps_${ENROOT_VERSION}-1_${arch}.deb && \
    unset arch && \
    apt install -y ./enroot*.deb && \
    rm enroot*.deb

The installation works, but running

enroot import -o /ubuntu.sqsh docker://ubuntu:24.04

leads to an error,

[INFO] Querying registry for permission grant
[INFO] Authenticating with user: <anonymous>
[INFO] Authentication succeeded
[INFO] Fetching image manifest list
[INFO] Fetching image manifest
[INFO] Found all layers in cache
[INFO] Extracting image layers...

100% 1:0=0s a3629ac5b9f4680dc2032439ff2354e73b06aecc2e68f0035a2d7c001c8b4114

[INFO] Converting whiteouts...

0% 0:1=0s a3629ac5b9f4680dc2032439ff2354e73b06aecc2e68f0035a2d7c001c8b4114                                                           
/usr/bin/bash: line 1: /usr/bin/enroot-aufs2ovlfs: Operation not permitted
100% 1:0=0s a3629ac5b9f4680dc2032439ff2354e73b06aecc2e68f0035a2d7c001c8b4114

My hope is to use this Docker image with Gitlab CI to import the built Docker images with enroot.