Nginx process structure

Usually Nginx is working in multiple thread mode, there will be a master process, it will prefork multiple children processes called worker processes. 

• Master is not worked for web client connection and session management. It only manages the children processes.
• Worker process handles the requests from clients (usually http/https) and servers them. The number of worker processes are decided by configuration

Configuration Syntax

user userid;

worker_processes  [number];   #define how many worker processes

events{

worker_connections [number];                #define how many connection one process can server

}

Sample configuration

user  nginx;

worker_processes  10;

the processes output

root      5031     1  0 13:41 ?        00:00:00 nginx: master process ./nginx

nginx     5032  5031  0 13:41 ?        00:00:00 nginx: worker process

nginx     5033  5031  0 13:41 ?        00:00:00 nginx: worker process

nginx     5034  5031  0 13:41 ?        00:00:00 nginx: worker process

nginx     5035  5031  0 13:41 ?        00:00:00 nginx: worker process

nginx     5036  5031  0 13:41 ?        00:00:00 nginx: worker process

nginx     5037  5031  0 13:41 ?        00:00:00 nginx: worker process

nginx     5038  5031  0 13:41 ?        00:00:00 nginx: worker process

nginx     5039  5031  0 13:41 ?        00:00:00 nginx: worker process

nginx     5040  5031  0 13:41 ?        00:00:00 nginx: worker process

nginx     5041  5031  0 13:41 ?        00:00:00 nginx: worker process

process 5031 is the master(parent) process

processes 5032-5041 are the worker (children) process

hardware and core configuration

low traffic website	medium traffic website	high traffic website
CPU : 2 cores, memory 2GB, visits ~ 1/s	CPU : 4 cores, memory 4GB, visits ~ 50/s	CPU : 8 cores, memory 12GB, visits ~ 1000/s
worker_processor 2; worker_priority -4; worker_cpu_affinity 01 10 events{      worker_connections 128; }	worker_processor 4; worker_priority 0; worker_cpu_affinity 0001 0010 0100 1000 events{      worker_connections 1024; }	worker_processor 8; worker_priority 0; events{      worker_connections 8192; }