安装mysql-5.7：
yum -y install mysql-community-server mysql-community-devel
启动mysql：
systemctl start mysqld
systemctl enable mysqld
查看mysql的随机密码：
grep ‘temporary password‘ /var/log/mysqld.log
进入mysql更改密码：
mysql -uroot -p‘eZa?x2q;&;l%‘
set global validate_password_policy=0;
set global validate_password_length=1;
ALTER USER ‘root‘@‘localhost‘ IDENTIFIED BY ‘redhat‘;
原文：https://blog.51cto.com/12834334/2363291