-# install a well known working rmr
-FROM python:3.7-alpine
-RUN apk update && apk add autoconf automake build-base cmake libtool ninja pkgconfig git
-RUN git clone --branch 1.8.1 https://gerrit.o-ran-sc.org/r/ric-plt/lib/rmr \
- && cd rmr \
- && mkdir build \
- && cd build \
- && cmake .. -DPACK_EXTERNALS=1 \
- && make install
-
-# a1 stage 2
-FROM python:3.7-alpine
-
-# copies
-COPY --from=0 /usr/local/lib64/libnng.so /usr/local/lib64/libnng.so
-COPY --from=0 /usr/local/lib64/librmr_nng.so /usr/local/lib64/librmr_nng.so
-COPY a1/ /tmp/a1
-COPY tests/ /tmp/tests
-COPY setup.py tox.ini /tmp/
-WORKDIR /tmp
-
-# dir that rmr routing file temp goes into
+
+# This builds an image for A1 based on ubuntu. The build takes between three and four
+# minutes depending on what was previously cached, and results in an image that is
+# roughly 260 MiB in size (as of May 2021)
+#
+
+FROM python:3.8 as build
+
+# upgrade pip as root
+RUN pip install --upgrade pip
+
+# pick up things for gevent build
+#
+RUN apt-get update
+RUN apt-get install -y gcc musl-dev make file libffi-dev g++
+
+# --- all root operations must be above this line ------------------------------------
+
+
+# create a simple user. This is only really needed in stage 2,
+# however this makes the copying easier and straighttforward;
+# the 'pip option --user' command doesn't do the same thing when
+# run as root.
+#
+RUN addgroup a1user && adduser --ingroup a1user a1user
+
+# switch to the non-root user for installing python things
+USER a1user
+
+# Speed hack; we install gevent before anything because when building repeatedly (eg during dev)
+# and only changing a1 code, we do not need to keep compiling gevent which takes forever
+RUN pip install --user gevent
+RUN pip install --user requests
+
+COPY setup.py /home/a1user/
+COPY a1/ /home/a1user/a1
+RUN pip install --user /home/a1user
+
+
+
+# ----- stage 2 ---------------------------------------------------------------------------------
+
+# It might be tempting to use python:3.8, but that image is more than
+# 800 GiB to start, and the final image size if it is used is over
+# 1 GiB!! Using the plain ubuntu image, then installing py3, and taking
+# things built in the first stage, the final image size isn't tiny, but should
+# be well under the 800GiB start for the python image.
+#
+FROM ubuntu:20.04
+
+# pick up reference to python so that we can get 3.8 and not the really old default
+
+RUN apt-get update \
+ && apt install -y software-properties-common \
+ && add-apt-repository ppa:deadsnakes/ppa \
+ && apt-get install -y python3.8 python3-pip wget \
+ && apt-get clean
+
+# fetch and install RMR and any other needed libraries
+#
+ARG RMR_VER=4.7.4
+ARG RMR_PKG_URL=https://packagecloud.io/o-ran-sc/release/packages/debian/stretch/
+
+RUN wget -nv --content-disposition ${RMR_PKG_URL}/rmr_${RMR_VER}_amd64.deb/download.deb
+RUN wget -nv --content-disposition ${RMR_PKG_URL}/rmr-dev_${RMR_VER}_amd64.deb/download.deb
+RUN dpkg -i rmr_${RMR_VER}_amd64.deb \
+ && dpkg -i rmr-dev_${RMR_VER}_amd64.deb \
+ && ldconfig
+
+# copy python modules; this makes the 2 stage python build work
+#
+COPY --from=build /home/a1user/.local /home/a1user/.local
+
+# create mount point for dir with rmr routing file as named below
+#