Nginx
Table of Contents
1. Abstract
Event Driven architecture enabling servicing thousands of concurrent requests
2. Basics
2.1. Design
- Has one master and several worker processes (recommended as the number of CPU cores available).
- the master managers the workers and is responsible for reading the configuration.
- the workers are what do the actual work and serve requests.
- the event driven architecture along with OS native mechanisms are used for the scheduling mechanisms.
2.2. Configuration
- the configuration file defines the state of nginx
- /usr/local/nginx/conf/nginx.conf
- /etc/nginx/nginx.conf
- /usr/local/etc/nginx/nginx.conf
- the config application is composed of:
- syntax validation
- accept master specific configs
- create new workers and notify older workers
- older workers stop accepting new requests and serve the ones that are active before a graceful death
2.3. Graceful shutdown
- graceful in here: serves old requests and stops accepting new ones before the workers exit
- send a quit signal to the master process
kill -s QUIT <nginx-master-pid>
2.4. State
- for all current relevant workers:
ps -aux | grep nginxshould do it- individual investigation of pids as needed via the file system's internals
2.5. Interface
- coms by signalling the master process with signals:
- stop, quit, reload, reopen
nginx -s stop, for instance