Environment with dysfunctional PID 1 that does not reap zombies

zombie.Dockerfile

# Environment with dysfunctional PID 1 that does not reap zombies
#
# One zombie process in created automatically upon interactive invocation.
# Use `ps -ef` to see it

FROM python:slim-buster
RUN apt-get update && apt-get -y install procps psmisc
RUN echo "bash -c 'sleep 1 & disown'" > /create-zombie.bash
CMD ["python", "-c", "import pty; pty.spawn(['bash', '--init-file', '/create-zombie.bash'])"]