Enable https (and disabling http) breaks authentication

[Xav Paice]

If we switch Nagios to only run via https, not http (i.e. remove port 80 entirely), the Thruk interface presents: "It seems like you are not authorized."

See https://github.com/sni/Thruk/issues/657

To fix:

https://thruk.org/documentation/faq.html#enable-https-tls-ssl-in-apache-webserver-for-thruk

Add Include /usr/share/thruk/thruk_cookie_auth.include to the vhost definition.

This step might require a change to the Nagios charm, depending on if there's a thruk-agent relation.

The other change that needs making is to set cookie_auth_restricted_url = https://localhost/thruk/cgi-bin/restricted.cgi in /etc/thruk/thruk_local.conf.

So far I've tested those changes but still authentication isn't working - I might also try removing cookie based auth to see if that works out.

[Adam Dyess (addyess)]

It turns out that on every config change on nagios charm,
/etc/apache2/sites-available/default-ssl.conf is completely re-written. interestingly enough thruk does a nice job on it's install to place the /usr/share/thruk/thruk_cookie_auth.include into the VirtualHost files, however this full rewrite in nagios doesn't take into account this inserted line.

I was able to have success without having to change /etc/thruk/thruk_local.conf

[Adam Dyess (addyess)]

My approach on this will be to create a new directory

/etc/apache2/vhost.d/

in which the nagios template for the VirtualHost includes anything from this directory with
```
  IncludeOptional /etc/apache2/vhost.d/*.include
```

Then in the thruk-agent charm, we can symlink:
  /etc/apache2/vhost.d/thruk_cookie_auth.include --> /usr/share/thruk/thruk_cookie_auth.include

Nagios: https://code.launchpad.net/~addyess/charm-nagios/+git/charm-nagios/+merge/387090
Thruk-Agent: https://code.launchpad.net/~addyess/charm-thruk-agent/+git/charm-thruk-agent/+merge/387091

[Adam Dyess (addyess)]

Released here: https://jaas.ai/u/bootstack-charmers-next/thruk-agent/2