We have a Discourse that’s been running for at least three years and yesterday I made the mistake of restarting the instance in the hope it would take a domain change. The instance is running and we can see nginx is seeing requests form outside, but all visitors are getting “502 Bad gateway” all the time. Here’s an example entry in the nginx error log:
2020/06/22 19:03:26 [error] 11742#11742: *158 connect() failed (111: Connection refused) while connecting to upstream, client: 22.214.171.124, server: <my domain>, request: "GET / HTTP/1.1", upstream: "http://127.0.0.1:3000/", host: "<my domain>"
There’s no webserver running outside Docker so the app.yml file simply forwards 80 and 443 into the container. But what is supposed to be on port 3000? Is it suppose to be Ruby / Rails?