mysql 5.8 安装

选择版本

mysql 这里通过rpm的方式安装，使用 MySQL 官方提供的安装包选择适合自己系统的包进行安装
到这个页面下选择适合自己系统的版本：
http://dev.mysql.com/downloads/mysql/

Select Operating System: 选择系统，如果是Linux CentOS 选 Red Hat即可，如果没有你的版本，选 Linux-generic。

Select OS Version: 选对应的版本，CentOS 7 选 Enterprise 7 x86, 64-bit。

最近添新增了一些CentOS7 的机器，就使用 Red Hat 的版本进行安装。

选择版本

御载旧版本

一定要御载干净，否则安装过程中有版本问题！！！
yum 和 rpm 两种方式二选一:
列出所有已安装的，但不在rpm中的包
yum list installed mysql
结果

mysql-libs.x86_64
yum -y remove mysql-libs.x86_64

等价于上面的命令
rpm -qa | grep mysql
结果

mysql80-community-release-el7-4.noarch
mysql-community-common-8.0.27-1.el7.x86_64

阿里去自带 MariaDB，并不是需要的直接御载。
移除

rpm -e mariadb-libs-5.5.60-1.el7_5.x86_64

下载

wget https://dev.mysql.com/get/Downloads/MySQL-8.0/mysql-8.0.27-1.el7.x86_64.rpm-bundle.tar

EL是Red Hat Enterprise Linux的简写

EL6 软件包用于在Red Hat 6.x, CentOS 6.x, and CloudLinux 6.x进行安装
EL7 软件包用于在Red Hat 7.x, CentOS 7.x, and CloudLinux 7.x的安装

下载文件

必须安装(注意顺序)

yum install libaio
sudo rpm -ivh mysql-community-common-8.0.27-1.el7.x86_64.rpm
sudo rpm -ivh mysql-community-client-plugins-8.0.27-1.el7.x86_64.rpm
sudo rpm -ivh mysql-community-libs-8.0.27-1.el7.x86_64.rpm
sudo rpm -ivh mysql-community-client-8.0.27-1.el7.x86_64.rpm
sudo rpm -ivh mysql-community-server-8.0.27-1.el7.x86_64.rpm

启动

systemctl start mysqld.service

查看服务状态

systemctl status mysqld.service

查看状态

修改密码

查看默认密码，这是一个生成的随机密码，复制出来后，修改成己的密码。

grep "password" /var/log/mysqld.log

mysql -u root -p

输入初始密码，此时不能做任何事情，因为MySQL默认必须修改密码之后才能操作数据库
格式：

ALTER USER 'root'@'localhost' IDENTIFIED BY 'new password';

输入：

ALTER USER 'root'@'localhost' IDENTIFIED BY 'abcdefg1234567';

成功提示：Query OK, 0 rows affected (0.01 sec)

如果提示：

ERROR 1819 (HY000): Your password does not satisfy the current policy requirements

说明密码不满足默认安全策略，把密码搞复杂一点，就是那种自己也记不住，只能靠复制粘贴的那种。
也可以调低安全策略：

set global validate_password_policy=0;
set global validate_password_length=1;

安全策略，非常有必要

要启动mysql服务的时候，有一些提示说明，在那里有一些有用的信息。
其中就有开启安全策略的方式:

/usr/bin/mysql_secure_installation

下面有很多选项，不用头疼：

Remove anonymous users? y 移除
移除 anonymous 用户

Disallow root login remotely? y
是否开启 root 远程访问？
选 Y 开启远程访问，这个需要考虑一下，如果是本地开发的话，不需要开，如果是不同机器上做主从复制的话，就开启

Remove test database? y
自带的测试数据库，移除。

Reload privilege tables now? y
重启数据库权限表。

Securing the MySQL server deployment.

Enter password for user root:
The 'validate_password' component is installed on the server.
The subsequent steps will run with the existing configuration
of the component.
Using existing password for root.

Estimated strength of the password: 100
Change the password for root ? ((Press y|Y for Yes, any other key for No) : n

 ... skipping.
By default, a MySQL installation has an anonymous user,
allowing anyone to log into MySQL without having to have
a user account created for them. This is intended only for
testing, and to make the installation go a bit smoother.
You should remove them before moving into a production
environment.

Remove anonymous users? (Press y|Y for Yes, any other key for No) : y
Success.


Normally, root should only be allowed to connect from
'localhost'. This ensures that someone cannot guess at
the root password from the network.

Disallow root login remotely? (Press y|Y for Yes, any other key for No) : y
Success.

By default, MySQL comes with a database named 'test' that
anyone can access. This is also intended only for testing,
and should be removed before moving into a production
environment.


Remove test database and access to it? (Press y|Y for Yes, any other key for No) : y
 - Dropping test database...
Success.

 - Removing privileges on test database...
Success.

Reloading the privilege tables will ensure that all changes
made so far will take effect immediately.

Reload privilege tables now? (Press y|Y for Yes, any other key for No) : y
Success.