From ubuntu:xenial MAINTAINER Andre Peters # Set noninteractive mode for apt-get ENV DEBIAN_FRONTEND noninteractive # Update RUN apt-get update # Start editing # Install package here for cache RUN apt-get -y install supervisor \ postfix \ sasl2-bin \ postfix \ postfix-mysql \ postfix-pcre \ rsyslog \ ca-certificates COPY supervisord.conf /etc/supervisor/supervisord.conf COPY postfix.sh /opt/postfix.sh RUN groupadd -g 5000 vmail RUN useradd -g vmail -u 5000 vmail -d /var/vmail EXPOSE 588 # Run CMD /usr/bin/supervisord -c /etc/supervisor/supervisord.conf