Nginx over apache gives 502 Bad Gateway

Question

I'm trying to run Nginx over Apache.

My configuration is that I set Apache to listen to port 8080 instead of 80.

Then I set Nginx to proxy all requests to the same domain over port 8080:

upstream app {
    server example.com:8080;
}
server {
    listen 80;
    server_name example.com;
    ssl_protocols TLSv1.2;
    charset utf-8;
    index index.html index.htm index.php;
    location = /favicon.ico { access_log off; log_not_found off; }
    location = /robots.txt  { access_log off; log_not_found off; }
    access_log off;
    error_log  /var/log/nginx/example.com-error.log error;
    location / {
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header X-Forwarded-Proto $scheme;
        proxy_set_header Host $http_host;
        proxy_set_header X-NginX-Proxy true;
        proxy_pass https://app/;
        proxy_redirect off;
        # Handle Web Socket connections
        proxy_http_version 1.0;
        proxy_set_header Upgrade $http_upgrade;
        proxy_set_header Connection "upgrade";
    }
}

Then I setup the Apache configuration, which seems to work just fine, cause I can access my site at http://example.com:8080 without problems.

<VirtualHost *>
    DocumentRoot "/home/forge/example.com"
    ServerName example.com
    ServerAlias www.example.com
    CustomLog /var/log/httpd/example_com_access.log common
    ErrorLog /var/log/httpd/example_com_error.log
        <Directory /home/forge/example.com/>
            Options Indexes FollowSymLinks
            AllowOverride All
            Require all granted
        </Directory>
</VirtualHost>

But when trying to go to http://example.com/ I get 502 Bad Gateway - nginx/1.8.0.

Any ideas how to fix this?

The reason I need this is that I have one web server which holds a lot of websites using Nginx, but I need some (only some of them) of the sites to run Apache rules instead of Nginx rules.

I am running Ubuntu 14.04.

EDIT: Here is the log from /var/log/nginx/error.log:

2015/11/06 11:05:27 [emerg] 18176#0: "proxy_pass" cannot have URI part in location given by regular expression, or inside named location, or inside "if" statement, or inside "limit_except" block in /etc/nginx/sites-enabled/thehostboy.com:71
2015/11/06 11:07:49 [emerg] 18564#0: "proxy_pass" cannot have URI part in location given by regular expression, or inside named location, or inside "if" statement, or inside "limit_except" block in /etc/nginx/sites-enabled/thehostboy.com:71
2015/11/06 11:23:25 [notice] 21045#0: signal process started
2015/11/06 11:23:25 [alert] 20875#0: *60679 open socket #4 left in connection 9
2015/11/06 11:23:25 [alert] 20875#0: *60680 open socket #41 left in connection 10
2015/11/06 11:23:25 [alert] 20875#0: *60678 open socket #46 left in connection 25
2015/11/06 11:23:25 [alert] 20875#0: *60677 open socket #45 left in connection 26
2015/11/06 11:23:25 [alert] 20875#0: aborting
2015/11/06 11:25:04 [notice] 21184#0: signal process started
2015/11/06 11:25:04 [alert] 21052#0: *97 open socket #3 left in connection 5
2015/11/06 11:25:04 [alert] 21052#0: *98 open socket #36 left in connection 11
2015/11/06 11:25:04 [alert] 21052#0: aborting
2015/11/06 11:27:02 [notice] 21294#0: signal process started
2015/11/06 11:28:39 [notice] 21378#0: signal process started

Solution

I fixed this by changing proxy_pass from https://... to http://....

Comments

[Lety]

try this: stackoverflow.com/questions/21662940/…

[Mark Topper]

@ThomasW., I just cleared the log and restarted nginx. And the only thing that comes into it is the line ending with signal process started, and it comes from restarting nginx. Nothing is logged for the Bad Gateway.

[Mark Topper]

Thanks @Lety, but I am quite sure this error was from when I had location /* { ... } while back when I tried anything in order to get it to work. It is also a report from long time ago, and nginx have been restarted many times since that.

[Mark Topper]

Solved changing proxy_pass to http://... instead of https://.... Feel stupid now... Thanks anyways guys.

[Thomas Ward]

@Mark post that as an answer to your question so you can accept it and mark the question as answered later.