Nginx's Too many open files, is setting of worker_rlimit_nofile enough?

Question

Is setting the right value of worker_rlimit_nofile in nginx.conf enough solve the issue of Too many open files in nginx?

Or do I still need to update the sysctl.conf and limits.conf?

Answer 1

In Linux, you can see if that option has changed the limits of the process by running:

cat /proc/<PID>/limits

Where <PID> is the process ID of nginex. Test on a development environment.

If that option is not changing the limits or if you have a too restrictive hard limit you need to change the nofile in the /etc/security/limits.conf file.

Answer 2

I do not think you need to modify limits.conf. The point of worker_rlimit_nofile is to provide a quick and dirty way to do this via RLIMIT_NOFILE.

However, there are hard system limits set by the OS which you may need to override using sysctl.conf.

In practice, I usually set my fs.file-max in sysctl to about 4X the rlimit for my apps. No basis for this other than I never want something to fail due to hitting this limit. And a 2-4X range is usually sufficiently high to only trigger when there's a major issue with the apps.