环境 OS：CentOS7.6 Mysql：Mysql5.7
- 获取更新包 Mysql官网:https://dev.mysql.com/ 到http://dev.mysql.com/downloads/repo/yum/ 去下载rpm包更新一下。
#下载mysql源安装包
wget http://dev.mysql.com/get/mysql57-community-release-el7-8.noarch.rpm
#安装mysql源
yum localinstall mysql57-community-release-el7-8.noarch.rpm
#检测源是否安装成功
yum repolist enabled | grep "mysql.*-community.*"
2. 安装
修改配置yum 安装mysql的版本，这里安装MySQL5.7版本，修改“enabled=1”。
vim /etc/yum.repos.d/mysql-community.repo
#Enable to use MySQL 5.6
[mysql56-community]
name=MySQL 5.6 Community Server
baseurl=http://repo.mysql.com/yum/mysql-5.6-community/el/7/$basearch/
enabled=0
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-mysql
[mysql57-community]
name=MySQL 5.7 Community Server
baseurl=http://repo.mysql.com/yum/mysql-5.7-community/el/7/$basearch/
enabled=1
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-mysql
yum安装
yum install mysql-community-server
systemctl start mysqld //启动mysql服务
systemctl status mysqld
systemctl enable mysqld
systemctl daemon-reload //重载服务
3. 配置
mysql5.7安装时会产生一个默认密码，查看此密码的文件一般存在于/var/log/mysqld.log上。
grep 'temporary password' /var/log/mysqld.log
登录mysql
mysql -uroot -p
可看到mysql5.7版本默认登录后要求修改密码，采用了密码机制，默认为medium，要求密码有大写字母及特殊字符。
修改密码：
mysql> set password for 'root'@'localhost'=password('xxxxxxxx');
查看密码策略：
mysql> show variables like '%password%'
0 => LOW，1 => MEDIUM，2 => STRONG
命令行修改：
set global validate_password_policy=0; //设置密码策略等级
set global validate_password_length=6； //设置密码最小长度
重启mysql服务
systemctl restart mysqld
