NGINX's architecture
NGINX consists of a single master process and multiple worker processes. Each of these processes is single-threaded and designed to handle thousands of connections simultaneously. The worker process is where most of the action takes place, as this is the component that handles client requests. NGINX makes use of the operating system's event mechanism to respond quickly to these requests.
The NGINX master process is responsible for reading the configuration, handling sockets, spawning workers, opening log files, and compiling embedded Perl scripts. The master process is the one that responds to administrative requests via signals.
The NGINX worker process runs in a tight event loop to handle incoming connections. Each NGINX module is built into the worker, so that any request processing, filtering, handling of proxy connections, and much more is done within the worker process. Due to this worker model, the operating system can handle each process separately...