yum install -y https://repo.mysql.com/mysql-community-release-el7.rpm
yum install -y mysql-community-server
systemctl enable mysqld
systemctl start mysqld

# 找临时密码
cat /var/log/mysqld.log

mysql -p 输入密码

set global validate_password.policy=0;
set global validate_password.length=1;
alter user 'root'@'localhost' identified by '新密码';

mysql -u root -p