How do I setup nginx for multiple upstream and load balancing?

Question

I am new to nginx config and I am trying to set up a reverse proxy using nginx and want to use load balancing of nginx to equally distribute the load on the two upstream servers of the upstream custom-domains i.e
server 111.111.111.11; server 222.222.222.22;.

Shouldn't the distribution be round robin by default? I have tried weights, no luck yet. This is what my server config looks like:

upstream custom-domains {
    server 111.111.111.11;
    server 222.222.222.22;
}
upstream cert-auth {
    server 00.000.000.000;
} 
server {
    listen       80;
    server_name  _;

   #access_log  /var/log/nginx/host.access.log  main;

    location / {
        proxy_pass http://custom-domains;
        proxy_http_version   1.1;
        proxy_set_header     Upgrade $http_upgrade;
        proxy_set_header     Connection upgrade;
        proxy_set_header     Host $host;
        proxy_cache_bypass   $http_upgrade;
    }
    location /.well-known/ {
        proxy_pass http://cert-auth;
    }
}

Right now all the load seems to be redirecting to just the first server i.e. 111.111.111.11.

Help is greatly appreciated! Thanks again.

unless your second server is down or not reachable, the config you pasted seems fine. And yes, default is round-robin. Can you check the logs on that server, make sure it's responding? Can you manually access it from the nginx server via curl? — Raul
I am getting errors in the error logs of both php-fpm and httpd ERROR: FPM initialization failed — Anmol Singh
httpd error looks like [mpm_worker:error] [pid 20560:tid 140188821104768] AH00286: server reached MaxRequestWorkers setting, consider raising the MaxRequestWorkers setting — Anmol Singh
So it means that your second webserver is having issues, and nginx checks detected that. Once a server is marked as unhealthy, nginx will not send requests to it. Fix your second webservers and everything will be good again. — Raul

Raul Raul · Accepted Answer · 2019-10-11T15:39:36

The config you posted is fine and should work in round-robin balance mode.

However, as you mentioned, your second webserver is having issues. Once those are fixed, your requests will be load balanced across both servers.

How do I setup nginx for multiple upstream and load balancing?

1 Answers