$uname -a
Linux debian 3.16.0-4-amd64 #1 SMP Debian 3.16.36-1+deb8u2 (2016-10-19) x86_64 GNU/Linux

$ulimit -Sn
65536

$ulimit -Hn
65536

worker_processes  4; # or 8
worker_rlimit_nofile 60000;

events {
    worker_connections  1024;
}

2016/11/03 05:13:44 [alert] 15#15: 1024 worker_connections are not enough
2016/11/03 05:13:44 [alert] 15#15: 1024 worker_connections are not enough

$netstat -anvpt | wc -l
1156   # or twice bigger if there is 8 worker processes.

worker_processes auto;