Nginx upstream block nondefault port

Question

experts.

I am trying to configure nginx/1.10.0 for upstream to 2 https web servers on non standart port with ssl termination.

Here is my current website setup in sites-available/

upstream backend {
        ip_hash;
        server 172.31.16.1:8444;
        server 172.31.16.2:8444;
}
server {
        listen 80;
        listen 443 ssl;
        listen 8444 ssl;
        ssl on;
        server_name backend_1;
        access_log /var/log/nginx/access.log;
        error_log  /var/log/nginx/error.log;
        ssl_session_cache shared:SSL:5m;

#--------ssl certificates for fronend------------#
        ssl_certificate /etc/nginx/ssl/nginxSvr.crt;
        ssl_certificate_key /etc/nginx/ssl/nginxSvr.key;
        ssl_verify_client off;

        location / {
        proxy_pass https://172.31.16.1;
#       proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_ssl_certificate /etc/nginx/ssl/IPSUMCUICA.crt;
        proxy_ssl_certificate_key /etc/nginx/ssl/IPSUMCUICA.key;
        proxy_ssl_session_reuse off;
        }

It works without using upstream section. But when I change proxy_pass to proxy_pass https://backend; I got an error 404, and https://backend:8444 in browser.

Apparently it tried to resolve this name and failed, probably after some error but error log is empty in this case. All suggestions are welcome. Thank you.

Answer 1

Somehow I found the solution. I have added proxy_set_header Host $http_host; in location directive. Now initial config works.

upstream backend {
        ip_hash;
        server 172.31.16.1:8444;
        server 172.31.16.2:8444; } 
server {
            listen 8444 ssl;
            server_name backend_1;
            access_log /var/log/nginx/access.log;
            error_log  /var/log/nginx/error.log info;
            ssl_session_cache shared:SSL:5m;

    ssl_certificate /etc/nginx/ssl/nginxSvr.crt;
    ssl_certificate_key /etc/nginx/ssl/nginxSvr.key;
    ssl_verify_client off;

    location / {
    proxy_pass https://backend;
    proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
    proxy_ssl_session_reuse off;
    proxy_set_header Host $http_host;
        }
}