You try to increase your connections to 1000 by editing /etc/mysql/my.cnf (change max_connections=1000) , but when you login to your database, you can only see your mysql only accept upto 214 connections?
It’s because the open_files_limit in Ubuntu system, here is the fix:
Edit
nano /lib/systemd/system/mysql.service
And add this line to the end:
LimitNOFILE=8192
Then run the 2 below commands or reboot the server
systemctl daemon-reload systemctl restart mysql.service