nginx.conf

events {
    worker_connections 10000;
}

http {
    access_log off;

    # Cache open file descriptors
    open_file_cache max=2000 inactive=20s;
    open_file_cache_valid 60s;
    open_file_cache_min_uses 2;
    open_file_cache_errors off;

    
    upstream api {
        server unix:/tmp01/api_01.sock max_fails=1 fail_timeout=9999m;
        server unix:/tmp02/api_02.sock max_fails=1 fail_timeout=9999m;
        server localhost:8081 backup;
        server localhost:8082 backup;
    }

    server {
        listen 9999;
        http2 on;

        location / {
            proxy_pass http://api;
            error_page 502 503 504 @fallback;
            proxy_buffering off;
        }

        location @fallback {
            proxy_pass http://api;
            proxy_buffering off;
        }
    }
}