Nginx Configuration Essentials

engine x — a high-performance open-source HTTP server, reverse proxy, and IMAP/POP3 mail proxy originally written by Igor Sysoev and first released in 2004.

A single master process that reads configuration, manages sockets, and spawns worker processes (default count = CPU cores). Workers handle all incoming connections using an event-driven, non-blocking loop.

Send SIGHUP to the master process (or run nginx -s reload). The master re-reads config, spawns new workers with the new config, and gracefully shuts down old workers after their connections drain.

stop sends SIGTERM to workers and forces them to exit immediately, closing open connections. quit sends SIGQUIT, which lets workers finish serving current requests before exiting.

nginx -t (or nginx -T to additionally dump the parsed configuration to stdout). Useful in CI/CD pipelines before a reload.

/etc/nginx/nginx.conf. Additional files are typically included via include /etc/nginx/conf.d/*.conf; and per-site configs in /etc/nginx/sites-enabled/.

include /path/to/file.conf; Glob patterns are supported, e.g. include /etc/nginx/conf.d/*.conf;.

http {} (HTTP server settings) and server {} (virtual host). Inside them live location {}, upstream {}, events {}, and the top-level main context.

The number of worker processes the master spawns. The conventional setting is worker_processes auto;, which detects the number of CPU cores.

A practical starting point is worker_connections 1024; (or higher, e.g. 4096/8192) inside the events {} block. Max clients ≈ worker_processes × worker_connections.

sendfile on; inside http {} or server {}. It lets nginx use the kernel zero-copy path, dramatically speeding up static transfers.

When enabled with sendfile, it instructs nginx to send response headers in one TCP packet (uses TCP_CORK). It is set with tcp_nopush on;.