Dockerfile

#use latest armv7hf compatible raspbian OS version from group resin.io as base image
FROM balenalib/armv7hf-debian:stretch

#enable building ARM container on x86 machinery on the web (comment out next line if built on Raspberry) 
RUN [ "cross-build-start" ]

#labeling
LABEL maintainer="netpi@hilscher.com" \
      version="V0.9.1.0" \
      description="Debian stretch with SSH and user root"

#version
ENV HILSCHERNETPI_DEBIAN_STRETCH 0.9.1.0

#install ssh, give user "root" a password
RUN apt-get update  \
    && apt-get install -y openssh-server \
    && echo 'root:root' | chpasswd \
    && sed -i 's/#PermitRootLogin prohibit-password/PermitRootLogin yes/' /etc/ssh/sshd_config \
    && sed 's@session\s*required\s*pam_loginuid.so@session optional pam_loginuid.so@g' -i /etc/pam.d/sshd \
    && mkdir /var/run/sshd \
    # && sed -i -e 's;Port 22;Port 23;' /etc/ssh/sshd_config \ #Comment in if other SSH port (22->23) is needed 

#SSH port
EXPOSE 22

#start SSH as service
ENTRYPOINT ["/usr/sbin/sshd", "-D"]

#set STOPSGINAL
STOPSIGNAL SIGTERM

#stop processing ARM emulation (comment out next line if built on Raspberry)
RUN [ "cross-build-end" ]