As podman is actively promoted by fedora and suse, im getting curious how to build a simple docker image with multiarch

Let use a simple Dockerfile of custom debian image

FROM debian:sid-slim
ARG USER=debian
ARG SUDOERS="$USER       ALL=(ALL) NOPASSWD:ALL"
ENV LC_ALL en_US.UTF-8
ENV LANG en_US.UTF-8
ENV LANGUAGE en_US.UTF-8
ENV DEBIAN_FRONTEND=noninteractive
ENV CONTAINERUSER=$USER
ENV TZ=Asia/Jakarta
ENV HOME=/home/$CONTAINERUSER
COPY sudo_lecture.txt /etc/sudo_lecture.txt
RUN apt update && \
    apt install -y --no-install-recommends eatmydata openssl sudo ca-certificates tzdata curl tini ncdu locales && \
    ln -s /usr/bin/eatmydata /usr/local/bin/apt && \
    apt clean && \
    rm -rf /var/lib/apt/lists/* && \
    ln -snf /usr/share/zoneinfo/$TZ /etc/localtime && \
    sed -i -e 's/# en_US.UTF-8 UTF-8/en_US.UTF-8 UTF-8/' /etc/locale.gen && \
    locale-gen && \
    echo "Defaults        lecture=always" >> /etc/sudoers && \
    echo "Defaults        lecture_file=/etc/sudo_lecture.txt" >> /etc/sudoers && \
    echo $SUDOERS >> /etc/sudoers && \  
    useradd -u 1000 -U -d /home/$USER -s /bin/bash -p $(echo $USER | openssl passwd -1 -stdin) $USER -m -d /home/$USER && \
    gpasswd -a $USER sudo && \
    mkdir -p /home/$CONTAINERUSER/.local/bin && \
    mkdir -p /home/$CONTAINERUSER/.local/lib && \
    chown -R $CONTAINERUSER:$CONTAINERUSER /home/$CONTAINERUSER

ENV PATH="/home/$CONTAINERUSER/.local/bin:/home/$CONTAINERUSER/.local/lib:/home/$CONTAINERUSER/.local/lib:$PATH"
WORKDIR $HOME
USER $CONTAINERUSER
ENTRYPOINT ["/usr/bin/tini", "-g", "--"]
CMD ["/bin/bash"]

First lets try simple build

podman build -t debian:local -f Dockerfile .

This is a standard and straigtforward command. Now the multiarch part

• on docker

  $ docker buildx build --push --platform linux/arm64,linux/amd64 -t repo/imagename:tag .

  In comparison

• on podman

  $ podman build --platform=linux/amd64,linux/arm64 --manifest repo/imagename:tag .

Both need qemu-user-static to work, or building cross architecture. or running binfmt support via docker

# docker run --rm --privileged martadinata666/docker-binfmt-qemu:sid