Multiple hostnames for a single site for cut-over phase

I know its not possible/supported to set up multiple hostnames (only multi-site), at least this is what the issue here says: How can I use multiple hostnames - support - Discourse Meta

However is that still the case? Redirect wont help in my case (and i really dont want to do fancy reverse proxy rewrites for a simple, temporary use case): In my case I want to install a new discourse server in parallel to the existing and have a staging view of this server with a new name. However the server should also accept the official name (for when the switch over in DNS happens or when admins use a /etc/hosts alias). This would greatly improve the staging phase.

I think currently the main problem are the absolute CSP URLs which stops this from working (hwoever since those already cdheck for protocol, they should be able to extend to check for hostnames from a list of allwoed hosts). So is this available … meanwhile?

BTW in my case I test with http, but I think the letsencrypt setup to request multiple certs is already covered here, so I will be able to do that later. (does not work until its available under the right official alias anyway)

BTW I just noticed that rebuilding the app container with a different DISCOURSE_HOSTNAME does not work - I suspect its also somewhere in the DB (but it cant be changed on the Admin settings).

Which makes it somewhat more important to have a list of accepted hosts for such a scenario.

There’s a topic for changing host names. Change the domain name or rename your Discourse

If you want multiple names to resolve and for Discourse to redirect to the right one, you’re all set for http. For https you’ll need to get a cert for all domains. I think Set up Let’s Encrypt with multiple domains should help.

If you want to have the site not redirect to itself, you can tweak the nginx to not do that redirect. I’m not sure how to tell you how to do it though.

The changing hostname topic does not work reliable for me (for example despite the remap+rebake the twitter-emoticons of the Welcome post point to wrong server) - havent researched why that is (will let you know). At least its not painless.

The redirect for my usescases does not work since it would redirect to the old server

nginx config does not need a change its not aware of the hostname. But the problem is more with the app, for example the CSP headers contain the full URL (no idea why).