How to set nginx max open files?

Question

Though I have done the following setting, and even restarted the server:

# head /etc/security/limits.conf -n2 www-data soft nofile -1 www-data hard nofile -1 # /sbin/sysctl fs.file-max fs.file-max = 201558 

The open files limitation of specific process is still 1024/4096:

# ps aux | grep nginx root       983  0.0  0.0  85872  1348 ?        Ss   15:42   0:00 nginx: master process /usr/sbin/nginx www-data   984  0.0  0.2  89780  6000 ?        S    15:42   0:00 nginx: worker process www-data   985  0.0  0.2  89780  5472 ?        S    15:42   0:00 nginx: worker process root      1247  0.0  0.0  11744   916 pts/0    S+   15:47   0:00 grep --color=auto nginx # cat /proc/984/limits Limit                     Soft Limit           Hard Limit           Units Max cpu time              unlimited            unlimited            seconds Max file size             unlimited            unlimited            bytes Max data size             unlimited            unlimited            bytes Max stack size            8388608              unlimited            bytes Max core file size        0                    unlimited            bytes Max resident set          unlimited            unlimited            bytes Max processes             15845                15845                processes Max open files            1024                 4096                 files Max locked memory         65536                65536                bytes Max address space         unlimited            unlimited            bytes Max file locks            unlimited            unlimited            locks Max pending signals       15845                15845                signals Max msgqueue size         819200               819200               bytes Max nice priority         0                    0 Max realtime priority     0                    0 Max realtime timeout      unlimited            unlimited            us 

I've tried all possible solutions from googling but in vain. What setting did I miss?

Answer 1

On CentOS (tested on 7.x):

Create file /etc/systemd/system/nginx.service.d/override.conf with the following contents:

[Service] LimitNOFILE=65536 

Reload systemd daemon with:

systemctl daemon-reload 

Add this to Nginx config file:

worker_rlimit_nofile 16384; (has to be smaller or equal to LimitNOFILE set above) 

And finally restart Nginx:

systemctl restart nginx 

You can verify that it works with cat /proc/<nginx-pid>/limits.

Answer 2

I found the answer in few minutes after posting this question...

# cat /etc/default/nginx # Note: You may want to look at the following page before setting the ULIMIT. #  http://wiki.nginx.org/CoreModule#worker_rlimit_nofile # Set the ulimit variable if you need defaults to change. #  Example: ULIMIT="-n 4096" ULIMIT="-n 15000" 

/etc/security/limit.conf is used by PAM, so it shoud be nothing to do with www-data (it's nologin user).