container with user johndoe, opam installed and initialized for that user

opam-container/Dockerfile

+FROM ubuntu:16.04
+
+MAINTAINER Yves Bertot <yves.bertot@inria.fr>
+
+RUN adduser --disabled-password --gecos "plain user" johndoe
+
+RUN apt-get -q -y update && \
+    apt-get -q -y dist-upgrade && \
+    apt-get -q -y install m4 rsync git && \
+    apt-get -q -y --no-install-recommends install ocaml-nox opam aspcud && \
+    apt-get -q -y clean
+
+USER johndoe
+
+ENV OPAMYES true
+ENV OPAMVERBOSE 0
+ENV OPAMJOBS 2
+
+RUN opam init -a && \
+    opam switch 4.04.0
+
+