There is native Docker support in shorewall 5 and my experiment should not be required anymore!
I think firewall rules integration was the biggest issue. Now that the shorewall developers fixed it we could integrate the solution (trivial):
# grep -n -i docker /etc/shorewall/* /etc/shorewall/shorewall.conf:174:DOCKER=No # <- change to "Yes"
I’ve no plans to develop neither an API nor a GUI for NethServer+Docker at this moment: there are too many use-case specific requirements (things that depend on what I install), and few general requirements (backup? front-end http?..). I’d start with a howto/prototype, as usual, to catch them all!