Mirroring Traffic with Nginx

Question

I need to duplicate/mirror the traffic comming to my server/resource.

I mean, I have server A and B and N (nginx) as webserver.

All the traffic comming to N/resource --> redirect to both A and B

Is it possible?

Answer 1

Nginx now has an http mirror module. Documentation is at https://nginx.org/en/docs/http/ngx_http_mirror_module.html

Example configuration from the documentation:

location / {
    mirror /mirror;
    proxy_pass http://backend;
}
location = /mirror {
    internal;
    proxy_pass http://test_backend$request_uri;
}

Answer 2

Here is new feature from nginx (1.13.4): http://nginx.org/en/docs/http/ngx_http_mirror_module.html#mirror

The ngx_http_mirror_module module (1.13.4) implements mirroring of an original request by creating background mirror subrequests. Responses to mirror subrequests are ignored.

Answer 3

Based on their README It looks that GOR could help you solving your problem.

I never used it before, just stumbled upon it this week, so good luck!

Answer 4

you cannot mirror requests with NGINX but the request is available as a variable. You could use Lua scripting to send that variable to a third party server as a sub request though. http://nginx.org/en/docs/http/ngx_http_core_module.html#var_request

Answer 5

After digging and digging I found a solution. You can see it here Copy and deliver a request to another nginx server for real traffic testing by @scari

Just thought I should mention it here to ease the search for other people. On my setup I didn't use uwsgi - instead I wanted to duplicate every incoming request to an additional servers (in addition to the backbones servers that was load balanced already.

Hope it will help,
Liron