Setting OS Limits with systemd

1. Edit /etc/systemd/user.conf and /etc/systemd/systemd.conf, add the following line to each file:

   DefaultLimitNOFILE=NEW_LIMIT
   

2. Edit /etc/security/limits.conf and set the usual limit details:

   USER soft nofile NEW_LIMIT
   USER hard nofile NEW_LIMIT
   

3. Restart your system for the changes to take effect.