Docker-in-Docker with Ubuntu Container

Dockerfile

FROM ubuntu:20.04

RUN set -ex \
    && apt update \
    && apt install --no-install-recommends -y \
          ca-certificates curl docker.io \
          # systemd is not a hard requirement for Amazon ECS Anywhere, but the installation script currently only supports systemd to run.
          # Amazon ECS Anywhere can be used without systemd, if you set up your nodes and register them into your ECS cluster **without** the installation script.
          systemd init \
    && rm -rf /var/lib/apt/lists/* \
    && rm -rf /usr/share/doc/* /usr/share/man/* /var/lib/apt/lists/* /tmp/* /var/tmp/*

RUN find /etc/systemd/system \
    /lib/systemd/system \
    -path '*.wants/*' \
    -not -name '*dbus*' \
    -not -name '*journald*' \
    -not -name '*systemd-tmpfiles*' \
    -not -name '*systemd-user-sessions*' \
    -exec rm \{} \; \
    && systemctl enable docker \
    && systemctl set-default multi-user.target

CMD ["/usr/sbin/init"]