EMFILE, Too many open files - Set ulimit parameters

I have a problem - got error for Sails js

EMFILE, Too many open files 

By default the number of open files  pro user in Centos  is 1024. In my case this number was  too small so I have to increase it.This is done with the  ulimit command:

$ulimit -a   # see all the kernel parameters
$ulimit -n   #see the number of open files
$ulimit -n 9000  #  set the number open files to 9000

The problem with this way is that the ulimit parameter is only set currently  for this command terminal and user.If you open a new tab and type again ulimit -a you will see that the number of open files is 1024.This means that after a reboot you’ll need to set the parameter again.

1.  First, in order to set this options automatically  you have to edit the etc/security/limits.conf file.

$sudo gedit /etc/security/limits.conf    #open the file in gedit

The # means that this part is commented.The wildcard * means  for all users.We need to set the nofile option meaning maximum number of open files.If you want to change the number of files of user, you should add this line in the limits.conf:

user  soft  nofile 9000

user  hard  nofile 65536

If  you want to set the nofile only for superuser you just write root instead of user.

root soft  nofile 9000

root hard  nofile 65536

2. Second step: 

Added to /etc/sysctl.conf:
fs.file-max = 65536

Then re-read the sysctl.conf:
/sbin/sysctl -p