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Comment by corobo | Hacker News Reader

Thank you for this, it's a decent start for me personally. I was previously using the DNS director in Varnish 3.x to do this which was removed in 4.x. The longer time goes on the more risk it is to be running older software so this has been a great help.

Oddly enough I'd never really considered nginx for the job despite using it to reverse proxy elsewhere. Sometimes you just need a poke in the right direction :)

Now I just need to figure a way to specify *.internaldomain so that nginx resolves www.example.com.internaldomain - where www.example.com is grabbed from the requested Host: header

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You can use the $host variable

See: http://nginx.org/en/docs/http/ngx_http_core_module.html#var_... And: http://stackoverflow.com/a/15414811

Always be careful with user input though.

well damn that's such a simple solution if that variable works in proxy_pass.. One of those "How did I miss that?" solutions

Of course rigorous testing before going live, but it gives options. I love options :)

It's good to hear it was of use to somebody :)

I know you can use a map in Nginx to do what you ask for, as long as you have a list of domains already: http://nginx.org/en/docs/http/ngx_http_map_module.html#map. I can only imagine it also being possible to make fully dynamic, I just don't have a clear way of doing it in mind right now.

The sibling comment to this pointed out the $host variable. I imagine something along the line of proxy_pass http://$host.internaldomain; or something on that line.

I'll have to look into it further :)

Lua + Redis is a nice way to do this, I have a small project https://github.com/spro/simon that does dynamic routing and load balancing based on Hostname -> IP:Port sets in Redis. Adding a new route is as simple as:

  sadd backends:hnapi.dev 192.168.0.42:10555

Neat! I want to get started on some Lua scripting as well, probably first to just get a bunch of metrics out of Nginx via StatsD. There's access to a whole bunch of numbers via Lua that you otherwise can't get out from the stub_status page.

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