Howto debug when nginx gives 502 bad gateway? - linux

Question

On landing.example.com:10000 have I a webserver that works fine, which is a Docker container that exposes port 10000. Its IP is 172.17.0.2.
What I would like is having a nginx reverse proxy on port 80, and send the visitor to different Docker containers depending on the URL they visit.
server {
listen 80;
server_name landing.example.com;
location / {
proxy_pass http://172.17.0.2:10000/;
}
access_log /landing-access.log;
error_log /landing-error.log info;
}
When I do this, I get 502 Bad Gateway and the log says
2016/04/14 16:58:16 [error] 413#413: *84 connect()
failed (111: Connection refused) while connecting to upstream, client:
xxx.xxx.xxx.xxx, server: landing.example.com, request: "GET / HTTP/1.1",
upstream: "http://172.17.0.2:10000/", host: "landing.example.com"

Answer 1

try this:
upstream my_server {
server 172.17.0.2:10000;
}
server {
listen 80;
server_name landing.example.com;
location / {
proxy_pass http://my_server;
proxy_set_header Host $host;
proxy_set_header X-Real-IP $remote_addr;
proxy_http_version 1.1;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_set_header X-Forwarded-Proto http;
proxy_redirect http:// $scheme://;
}
}
Here you define the upstream server (your server by IP or hostname)
and make sure to forward the headers too so the server answering knowns who to answer to.