[Samba] Container setup - selftests not running?

[Joachim Lindenberg]

Following my questions in https://lists.samba.org/archive/samba/2019-July/224115.html and the lack of recent builds of Samba in Ubuntu, I started to build Samba on my own. 
I installed a new virtual machine with Ubuntu 18.04.2 (LTS) server (+ssh), installed docker and docker-compose, and then tried to build using the following Dockerfile:

--- Dockerfile begin ---
# https://docs.docker.com/develop/develop-images/multistage-build/
# https://docs.docker.com/engine/reference/builder/#understand-how-arg-and-from-interact

# https://wiki.samba.org/index.php/Build_Samba_from_Source
# obviously you can only switch to distros also using apt :(

ARG distro=ubuntu:18.04
ARG dependencylist=ubuntu1804
ARG version=4.10.5
FROM ${distro} as samba-dev
ARG dependencylist
ARG version
RUN apt-get update && apt-get install -y wget
# TODO: can we reference the release branch of the version above?
RUN wget -O deps "https://git.samba.org/?p=samba.git;a=blob_plain;f=bootstrap/generated-dists/${dependencylist}/bootstrap.sh;hb=master"
RUN chmod +x deps && ./deps
RUN wget https://download.samba.org/pub/samba/stable/samba-${version}.tar.gz
RUN tar -zxf samba-${version}.tar.gz
RUN cd samba-${version} && ./configure --enable-selftest && make && make test && make install
--- Dockerfile end ---

I thought it is a good idea to also run tests... unfortunately they fail. Because of that I essentially ran the same steps also on the host, and they fail as well, though apparently not exactly the same tests fail. I noticed that during installation of krb on host, a configuration was created, whereas in the container the runlevel was inadequate. Because of that observation I suspect that it is a configuration or environment issue, as neither host nor container have a real configuration to run samba - but what configuration is really required to run the tests successfully? krb5.conf, smb.conf, a domain join, or what?

Thanks & Best Regards, Joachim