Before you study the management procedures of Nginx, you need to get some idea of how Nginx processes connections. In the full-scale mode, a single Nginx instance consists of the master process and worker processes, as shown in the following figure:
The master process spawns worker processes and controls them by sending and forwarding signals and listening for quit notifications from them. Worker processes wait on listening sockets and accept incoming connections. The operating system distributes incoming connections among worker processes in a round-robin fashion.
The master process is responsible for all startup, shutdown, and maintenance tasks such as the following:
Reading and re-reading configuration files
Opening and reopening log files
Creating listening sockets
Starting and restarting worker processes
Forwarding signals to the worker processes
Starting a new binary
The master process thus ensures continuous operation of an Nginx instance in the...