Update nginx to improve worker process and connection values

images/nginx/1.13/conf/nginx.conf

@@ -1,10 +1,13 @@
-worker_processes 1;
+# let's assume dual-core machine
+worker_processes 2;
 
 error_log /var/log/nginx/error.log debug;
 pid /var/run/nginx.pid;
 
 events {
-  worker_connections 1024;
+  # this should be equal to value of "ulimit -n"
+  # reference: https://www.digitalocean.com/community/tutorials/how-to-optimize-nginx-configuration
+  worker_connections 1048576;
 }
 
 http {