Nginx: Proxy to another nginx instance: Gateway time-out

user_7085728 0
Viewed 154

I have two nginx instances that I will call application and main. I have many reasons to do this.

The main instance running in front is reachable. If I replace its proxy_pass directive with return 200;, I get a 200 response. However, whether I return 200; in application, or I try to make it do what it's actually supposed to do (proxy again to a third app), it never receives the request.

The request eventually fails with 504 Gateway Time-out.

There's nothing out of the ordinary in any logs. The docker logs show the exact same output as when it was working just a few days ago, except there is no output for when I made the request, because the request is never received/registered. It basically stops at "startup complete; waiting for requests". So the app never receives the request in the first place when going through the reverse proxy. There's nothing at all in the nginx logs in either of the nginx containers.

Here's a minimal, reproducible example: https://github.com/Audiopolis/MultiServerRepro

I am not able to get the above example working. I randomly did for a little bit on Windows 10 (but not on Ubuntu 20.04), but it's not working any more. Can you see anything wrong with the configuration in the example?

The end goal is to easily add several applications to the same server using non-standard ports being proxied to by one "main" instance of nginx, which selects the appropriate app based on the host name. Note that each application must be capable of running on its own with its own nginx instance as well.

Thanks.

docker-compose docker nginx
1 Answers

Both your application and main nginx are running in different docker networks. main is mapping ports 80:80 and application is mapping ports 10000:80. The mapping is to the host machine so main can't proxy_pass to application.

There are a lot of ways to solve it but I will suggest 2:

  1. Run main with network: host and remove the port forwarding from main (since it's not needed anymore). NOTE: Network host is working only on linux machines (No windows)

  2. Run both nginx servers on the same docker network and then main can proxy_pass to application using docker network address, which is also mapped to it's docker container name (e.g: proxy_pass application_container_name:80).

user_53724620
Related