2019-12-30安装mysql

安装MySQL：

1. 清除掉所有跟mariadb相关的东西
   yum list installed | grep mariadb | awk '{print $1}' | xargs yum erase -y
2. 清理之前的数据和日志文件（如果存在）
   rm -rf /var/lib/mysql
   rm -f /var/log/mysqld.log
3. 下载MySQL官方提供的RPM包并解归档
   wget https://dev.mysql.com/get/Downloads/MySQL-5.7/mysql-5.7.28-1.el7.x86_64.rpm-bundle.tar
   tar -xvf mysql-5.7.28-1.el7.x86_64.rpm-bundle.tar
4. 安装依赖库
   yum install -y libaio
5. 使用rpm包管理工具安装MySQL
   rpm -ivh mysql-community-common-5.7.28-1.el7.x86_64.rpm
   rpm -ivh mysql-community-libs-5.7.28-1.el7.x86_64.rpm
   rpm -ivh mysql-community-client-5.7.28-1.el7.x86_64.rpm
   rpm -ivh mysql-community-server-5.7.28-1.el7.x86_64.rpm
6. 启动服务查看随机密码
   systemctl start mysqld
   cat /var/log/mysqld.log | grep password
7. 用客户端工具连接MySQL
   mysql -u root -p
8. 修改root用户口令
   set global validate_password_policy=0;
   set global validate_password_length=6;
   alter user 'root'@'localhost' identified by '123456';