Docker nginx reverse proxy gives "502 Bad Gateway"

Question

I'm trying to have a docker container with nginx work as reverse proxy to other docker containers and I keep getting "Bad Gateway" on locations other other than the base location '/'.

I have the following server block:

server {    listen 80;    location / {     proxy_pass "http://game2048:8080";   }    location /game {     proxy_pass "http://game:9999";   }  } 

It works for http://localhost but not for http://localhost/game which gives "Bad Gateway" in the browser and this on the nginx container:

[error] 7#7: *6 connect() failed (111: Connection refused)  while connecting to upstream, client: 172.17.0.1, server: ,  request: "GET /game HTTP/1.1", upstream: "http://172.17.0.4:9999/game",  host: "localhost" 

I use the official nginx docker image and put my own configuration on it. You can test it and see all details here: https://github.com/jollege/ngprox1

Any ideas what goes wrong?

NB: I have set local hostname entries on docker host to match those names:

127.0.1.1       game2048 127.0.1.1       game 

Answer 1

I fixed it! I set the server name in different server blocks in nginx config. Remember to use docker port, not host port.

server {    listen 80;   server_name game2048;    location / {     proxy_pass "http://game2048:8080";   }  }  server {    listen 80;   server_name game;    location / {     # Remember to refer to docker port, not host port     # which is 9999 in this case:     proxy_pass "http://game:8080";   }  } 

The github repo has been updated to reflect the fix, the old readme file is there under ./README.old01.md.

Typical that I find the answer when I carefully phrase the question to others. Do you know that feeling?