Shibboleth SP on Ubuntu 18.04

[Peter Schober]

* Mundry, Marvin <Marvin.Mundry at uni-hamburg.de> [2018-10-12 17:30]:
> I would like to run a rails application served by an apache server
> with the apache2 shibboleth module on Ubuntu 18.04.

Ubuntu is not a good GNU/Linux distribution to deploy the Shib SP
on. (Actually the worst of all the popular ones, AFAICT.)

The shib packages are not part of any Ubuntu-supported release channel
(they're in "universe", somewhat supported by
https://wiki.ubuntu.com/MOTU) and I don't think anyone has done any
real packaging work there, other than pulling from Debian.
I do note there's a 3.0.2 package for cosmic listed on
packages.ubuntu.com that's not from Debian, as SPv3 still waits to
propagate through the proper channes on the Debian side.
(To be expected in Debain "stretch" backports Really Soon Now.)

> Is there a way to get the combination of
> - rails/passenger
> - shibboleth-sp
> - and ubuntu 18.04 
> to work?

Maybe not in the literal sense, but have you considered using uwsgi
instad of Passenger Phusion?
I've used mod_proxy_uwsgi (over a UNIX socket) + mod_shib successfully
with all kinds of applications managed by uwsgi (Python/WSGI,
Perl/PSGI, etc.)

You'll at least want packages: uwsgi-core, libapache2-mod-proxy-uwsgi
and one of the ruby plugins, for 18.04LTS that's probably
uwsgi-plugin-rack-ruby2.5.

Possible starting points:
https://uwsgi-docs.readthedocs.io/en/latest/RackQuickstart.html
https://uwsgi-docs.readthedocs.io/en/latest/Ruby.html
https://uwsgi-docs.readthedocs.io/en/latest/Apache.html

All of that should applies to Debian 9, too (modulo version
differences), for which supported (by the Debian packaging team, and
with Scott's help) and current Shibboleth packages will shortly be
available from backports.

-peter