Using Domain Names in proxy_pass directive

Server NGINX
1

Hi

I am using nginx as reverse proxy with FQDN for the backend server .

My configuration for the location block looks like this :-

location / {

set $ustreamsbc sbc.example.com ;
proxy_pass HTTPS://$ustreamsbc ;

            proxy_next_upstream error timeout invalid_header

http_500
http_502 http_503 http_504;

            proxy_connect_timeout 10s ;
            include /usr/local/nginx/conf/proxy.conf ;



            proxy_redirect     off;
  }

I have a resolver in place for this FQDN and its running fine.

My doubt is that if I change the mapped IP for this FQDN in the DNS
server ,
would nginx re-resolve the FQDN to the new IP for all the future
requests.

Also does nginx honor TTL for all the FQDN stored in variables as shown
above ??

Thanks and Regards

Shobhit M.

Posted at Nginx Forum:

2

On Fri, May 23, 2014 at 07:39:36AM -0400, Shobhit M. wrote:

Shobhit M.

nginx will re-resolve names as configured by the
Module ngx_http_core_module directive. By default,
the TTL of the response is honored but it can be
overridden.

(Whether the queried server has an up-to-date info
is another question.)

3

Thanks Ruslan for the reply …

I have another query regarding this …

I am planning to use more than one backend servers for supporting Load
balancing.

I would be using an upstream block for the same.

My default configuration is as below :

upstream us1
{
server sbc.example1.com:443 ;
server sbc.example2.com:443 ;

}

and the location block is

location / {

proxy_pass HTTPS://us1 ;

            proxy_next_upstream error timeout invalid_header

http_500
http_502 http_503 http_504;

            proxy_connect_timeout 10s ;
            include /usr/local/nginx/conf/proxy.conf ;



            proxy_redirect     off;
  }

Does nginx honor TTL for the FQDN in the upstream block as well ??

As per my understanding nginx resolves FQDN in upstream blocks only
during
configuration parsing …

Please suggest on this.

Thanks

Shobhit M.

Posted at Nginx Forum:

4

On Friday 23 May 2014 08:41:09 Shobhit M. wrote:
[…]

Does nginx honor TTL for the FQDN in the upstream block as well ??

As per my understanding nginx resolves FQDN in upstream blocks only during
configuration parsing …

Please suggest on this.

Look at the “resolve” parameter:
http://nginx.org/en/docs/http/ngx_http_upstream_module.html#server

wbr, Valentin V. Bartenev

5

This solution would really help .

Thanks a lot for the info … :slight_smile:

Regards

Shobhit M.

Posted at Nginx Forum: