I just want to set ulimit -n (per process max open files) and for the setting to survive reboots, but it's proving difficult.

I don't know where else to change things to allow it to be set.

```
root@z:~# cat /etc/sysctl.conf | grep file-max
fs.file-max = 2000000
root@z:~# cat /etc/security/limits.conf | grep nofile
#        - nofile - max number of open files
* soft     nofile         2000000   
* hard     nofile         2000000
root@z:~# sudo sysctl -p | grep file
fs.file-max = 2000000
root@z:~# ulimit -n 2000000
-su: ulimit: open files: cannot modify limit: Operation not permitted
root@z:~# whoami
root

```

strangley this lower setting on the other hand works:

```
ulimit -n 1048576

```

Please let me know how to set per-process limit to 2000000 and for the setting to be maintained across reboots, I am on Ubuntu 18.04