502 Bad Gateway - nginx/1.14.0 (Ubuntu)

[Francis Daly]

On Sun, Nov 17, 2019 at 06:40:36AM -0500, naupe wrote:

Hi there,

> > root at ngx:/etc/nginx/sites-available# less /var/log/nginx/error.log
> > 2019/11/17 06:01:24 [error] 23646#23646: *37 connect() failed (111:
> Connection refused) while connecting to upstream, client: 1.2.3.4, server:
> discourse.domainame.com, request: "GET / HTTP/2.0", upstream:
> "http://5.6.7.8:8080/", host: "discourse.domainame.com"
> 
> * 1.2.3.4 = My Old Public IP Address
> * 5.6.7.8 = My New Public IP Address

nginx is trying, and failing, to connect to 5.6.7.8:8080.

Should nginx be trying to connect to 5.6.7.8? If so, fix the network so
that it is able to connect there. If not, fix the nginx config so that
it tries to connect to the place that you want.

> My /etc/nginx/sites-available CONF file for the Discourse Site can be found
> in THIS link: https://pastebin.com/fiiyATeP

The relevant bit there seems to be

    location / {
      proxy_pass http://discourse.domainname.com:8080/;

> * 192.168.0.101 = Nginx VM
> * 192.168.0.104 = Discourse VM

When nginx starts, it will ask the system to resolve the name
discourse.domainname.com, and it (presumably) is told 5.6.7.8.

It looks to me like you want that to be 192.168.0.104 instead.

In that case - either change the system resolver; or just change the
proxy_pass line to use the 192.168.0.104 IP address instead of the
hostname.

(Other options exist too; these are probably the ones with fewest
changes.)

Good luck with it,

	f
-- 
Francis Daly        francis at daoine.org