Setting NGINX File Descriptor Limits

Configure the www-data user to have 8192 open files. This should match or exceed the worker_rlimit_nofile setting in NGINX config.

Edit /etc/security/limits.d/10-nofile.conf:

www-data soft nofile 8192
www-data hard nofile 8192

Note: Files in /etc/security/limits.d/ are processed after /etc/security/limits.conf and are preferred for custom configurations.

Create the override directory and file:

mkdir -p /etc/systemd/system/nginx.service.d

Create /etc/systemd/system/nginx.service.d/override.conf:

[Service]
LimitNOFILE=8192

Reload systemd:

systemctl daemon-reload

Important: For systemd-managed services, this override takes precedence over /etc/security/limits.d/ settings.

Edit /etc/nginx/nginx.conf and add at the top level (outside any block):

worker_rlimit_nofile 8192;