Has anyone hit this issue trying to build a Phoenix app within a docker container?
It get’s stuck at the # Rebuilding step:
[+] Building 1461.1s (24/31) docker:orbstack
=> => transferring context: 146.18MB 0.9s
=> [stage-1 1/6] FROM docker.io/library/ubuntu:bionic-20230126@sha256:a3765b4d74747b5e9bdd03205b3fbc4fa1 0.0s
=> CACHED [stage-1 2/6] RUN apt-get update -y && apt-get install -y libstdc++6 openssl libncurses5 loc 0.0s
=> CACHED [stage-1 3/6] RUN sed -i '/en_US.UTF-8/s/^# //g' /etc/locale.gen && locale-gen 0.0s
=> CACHED [stage-1 4/6] WORKDIR /app 0.0s
=> CACHED [stage-1 5/6] RUN chown nobody /app 0.0s
=> CACHED [builder 2/20] RUN apt-get update -y && apt-get install -y build-essential git erlang-ssl 0.0s
=> [builder 3/20] RUN mkdir /client 0.2s
=> [builder 4/20] COPY client /client 0.4s
=> [builder 5/20] WORKDIR /app 0.0s
=> [builder 6/20] RUN mix local.hex --force && mix local.rebar --force 39.7s
=> [builder 7/20] COPY portal/mix.exs portal/mix.lock ./ 0.0s
=> [builder 8/20] RUN mix deps.get --only prod 25.0s
=> [builder 9/20] RUN mkdir config 0.3s
=> [builder 10/20] COPY portal/config/config.exs portal/config/prod.exs config/ 0.0s
=> [builder 11/20] RUN mix deps.compile 58.7s
=> [builder 12/20] COPY portal/priv priv 0.1s
=> [builder 13/20] COPY portal/lib lib 0.0s
=> [builder 14/20] COPY portal/assets assets 0.0s
=> [builder 15/20] RUN mix assets.deploy 1321.6s
=> => # 15:18:44.982 [debug] Downloading tailwind from https://github.com/tailwindlabs/tailwindcss/releases/do
=> => # wnload/v3.2.4/tailwindcss-linux-x64
=> => # Rebuilding...
The only non standard wrinkle is I’m using an amd64 ubuntu image to build the app on an M1 Mac. This was working fine in an earlier version so I’m starting to tear my hair out trying to figure out what’s changed! 
This is my Dockerfile:
# Find eligible builder and runner images on Docker Hub. We use Ubuntu/Debian
# instead of Alpine to avoid DNS resolution issues in production.
#
# https://hub.docker.com/r/hexpm/elixir/tags?page=1&name=ubuntu
# https://hub.docker.com/_/ubuntu?tab=tags
#
# This file is based on these images:
#
# - https://hub.docker.com/r/hexpm/elixir/tags - for the build image
# - https://hub.docker.com/_/debian?tab=tags&page=1&name=bullseye-20231009-slim - for the release image
# - https://pkgs.org/ - resource for finding needed packages
# - Ex: hexpm/elixir:1.16.0-erlang-26.2.1-debian-bullseye-20231009-slim
#
ARG ELIXIR_VERSION=1.15.3
ARG OTP_VERSION=26.0.2
ARG UBUNTU_VERSION=bionic-20230126
ARG BUILDER_IMAGE="hexpm/elixir:${ELIXIR_VERSION}-erlang-${OTP_VERSION}-ubuntu-${UBUNTU_VERSION}"
ARG RUNNER_IMAGE="ubuntu:${UBUNTU_VERSION}"
FROM --platform=linux/amd64 ${BUILDER_IMAGE} as builder
# install build dependencies
RUN apt-get update -y && apt-get install -y build-essential git erlang-ssl \
&& apt-get clean && rm -f /var/lib/apt/lists/*_*
RUN mkdir /client
COPY client /client
# prepare build dir
WORKDIR /app
# install hex + rebar
RUN mix local.hex --force && \
mix local.rebar --force
# set build ENV
ENV MIX_ENV="prod"
ENV ERL_FLAGS="+JPperf true"
# install mix dependencies
COPY portal/mix.exs portal/mix.lock ./
RUN mix deps.get --only $MIX_ENV
RUN mkdir config
# copy compile-time config files before we compile dependencies
# to ensure any relevant config change will trigger the dependencies
# to be re-compiled.
COPY portal/config/config.exs portal/config/${MIX_ENV}.exs config/
RUN mix deps.compile
COPY portal/priv priv
COPY portal/lib lib
COPY portal/assets assets
# compile assets
RUN mix assets.deploy
# Compile the release
RUN mix compile
# Changes to config/runtime.exs don't require recompiling the code
COPY portal/config/runtime.exs config/
COPY portal/rel rel
RUN mix release
RUN ls /app/_build/${MIX_ENV}/
# start a new build stage so that the final image will only contain
# the compiled release and other runtime necessities
FROM ${RUNNER_IMAGE}
RUN apt-get update -y && \
apt-get install -y libstdc++6 openssl libncurses5 locales ca-certificates \
&& apt-get clean && rm -f /var/lib/apt/lists/*_*
# Set the locale
RUN sed -i '/en_US.UTF-8/s/^# //g' /etc/locale.gen && locale-gen
ENV LANG en_US.UTF-8
ENV LANGUAGE en_US:en
ENV LC_ALL en_US.UTF-8
WORKDIR "/app"
RUN chown nobody /app
# set runner ENV
ENV MIX_ENV="prod"
ENV DATABASE_PATH="..."
ENV SECRET_KEY_BASE="..."
# Only copy the final release from the build stage
COPY --from=builder --chown=nobody:root /app/_build/${MIX_ENV} ./
USER nobody
# If using an environment that doesn't automatically reap zombie processes, it is
# advised to add an init process such as tini via `apt-get install`
# above and adding an entrypoint. See https://github.com/krallin/tini for details
# ENTRYPOINT ["/tini", "--"]
CMD ["/bin/bash"]
