This solutions is application to cpnginx and danginx plugins and bare nginx server configurations.

Edit the file /etc/sysctl.conf and increase the openfile limits. Add the following line,

fs.file-max = 700000

Edit /etc/security/limits.conf and add the following lines,

nobody soft nofile 100000
nobody hard nofile 500000

Now apply the sysctl configuration using the following command .

# sysctl -p

Now edit the /usr/local/nginx/conf/nginx.conf file and add the following line.

worker_rlimit_nofile 50000;

Now stop nginx server and restart.