/etc/mysql/mariadb.conf.d/50-server.cnf
bind-address
127.0.0.1
0.0.0.0
CREATE USER '用户名'@'%' IDENTIFIED BY '密码'
GRANT ALL PRIVILEGES ON *.* TO '用户名'@'%' WITH GRANT OPTION
FLUSH PRIVILEGES
ufw allow 3306/tcp
sudo systemctl status mariadb
sudo systemctl start mariadb
ping
telnet
/var/log/mysql/error.log