What are the ways to increase resource limits for the nginx server?

To increase resource limits in nginx, several approaches can be used:

1. System limits configuration — nginx depends on system restrictions such as the maximum number of open files (ulimit). To increase the limit, you need to change parameters in the system:

   • Change the open files limit for the user running nginx, for example, via ulimit -n or in the /etc/security/limits.conf file.
   • Ensure that kernel parameters (e.g., fs.file-max) allow opening more files.

2. nginx parameter configuration:

   • worker_connections — the maximum number of connections one worker process can handle.
   • worker_processes — the number of nginx worker processes.

   Increasing these parameters allows nginx to serve more clients simultaneously.

3. TCP/IP stack parameter configuration:

   • Increase values of parameters such as net.core.somaxconn, net.ipv4.ip_local_port_range, tcp_tw_reuse, and others to improve handling of a large number of connections.

4. Scaling:

   • Run multiple nginx instances or use load balancers.

Example of changing the open files limit for the nginx user in /etc/security/limits.conf:

nginx   soft    nofile  65535
nginx   hard    nofile  65535

And in the nginx config (nginx.conf):

worker_processes  auto;
worker_connections  10240;