Increate max no of open files limit in Ubuntu 16.04/18.04 for Nginx

gistfile1.txt

# maximum capability of system
user@ubuntu:~$ cat /proc/sys/fs/file-max
708444

# available limit
user@ubuntu:~$ ulimit -n
1024

# To increase the available limit to say 200000
user@ubuntu:~$ sudo vim /etc/sysctl.conf

# add the following line to it
fs.file-max = 200000

# run this to refresh with new config
user@ubuntu:~$ sudo sysctl -p

# edit the following file
user@ubuntu:~$ sudo vim /etc/security/limits.conf

# add following lines to it

* soft  nofile  200000   
* hard  nofile  200000
www-data  soft  nofile  200000
www-data  hard  nofile  200000
root soft nofile 200000   
root hard nofile 200000

# edit the following file
user@ubuntu:~$ sudo vim /etc/pam.d/common-session

# add this line to it
session required pam_limits.so

# logout and login and try the following command
user@ubuntu:~$ ulimit -n
200000

# now you can increase no.of.connections per Nginx worker
# in Nginx main config /etc/nginx/nginx.conf
worker_connections 200000;
worker_rlimit_nofile 200000;

One more point, if you use systemd, then need edit
/etc/systemd/system/nginx.service.d/nofile.conf

[Service]
LimitNOFILE=65536

Shouldn't L16 add the /etc/sysctl.conf file?

user@ubuntu:~$ sudo sysctl -p

Doesn't work for Ubuntu 18.04

I just updated the gist by adding nginx config worker_rlimit_nofile and followed all of the steps in Ubuntu 18.04. I could see the limit increase during the last ulimit -n step.

Doesn't work for Ubuntu 18.04

It seems that on Ubuntu 18.04 one should set a separate limit for graphical login.
Checkout this topic for more info.

Cool, Thanks!

Must restart!
Change the maximum number of open files in ubuntu 18.10

Must restart! Change the maximum number of open files in ubuntu 18.10

not necessary. at least in 18.04