Ubuntu下MySQL的安装

1. 安装

sudo apt-get update
sudo apt-get install -y mysql-server mysql-client

2. 数据库初始化

sudo mysql_secure_installation

交互如下：

Securing the MySQL server deployment.

Connecting to MySQL using a blank password.

VALIDATE PASSWORD PLUGIN can be used to test passwords
and improve security. It checks the strength of password
and allows the users to set only those passwords which are
secure enough. Would you like to setup VALIDATE PASSWORD plugin?

Press y|Y for Yes, any other key for No: y

There are three levels of password validation policy:

LOW    Length >= 8
MEDIUM Length >= 8, numeric, mixed case, and special characters
STRONG Length >= 8, numeric, mixed case, special characters and dictionary                  file

Please enter 0 = LOW, 1 = MEDIUM and 2 = STRONG: 2  <=====注意这里一定要选2，STRONG
Please set the password for root here.

New password: 

Re-enter new password: 

Estimated strength of the password: 100 
Do you wish to continue with the password provided?(Press y|Y for Yes, any other key for No) : y
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.

All done! 

3. 不使用sudo访问MySQL（$ mysql -uroot -p）要求对MySQL设置最高密码强度

Please enter 0 = LOW, 1 = MEDIUM and 2 = STRONG: 2

4. 启动MySQL

sudo systemctl start mysql.service
sudo systemctl enable mysql.service
sudo systemctl status mysql.service

5. 权限设定（可选）

mysql> use mysql;
mysql> select User,Host,plugin from user;
+------------------+-----------+-----------------------+
| User             | Host      | plugin                |
+------------------+-----------+-----------------------+
| root             | localhost | auth_socket <--这里   |
| mysql.session    | localhost | mysql_native_password |
| mysql.sys        | localhost | mysql_native_password |
| debian-sys-maint | localhost | mysql_native_password |
+------------------+-----------+-----------------------+

mysql> update user set plugin='mysql_native_password' where User='root' and Host='localhost';
mysql> GRANT ALL PRIVILEGES ON *.* TO 'root'@'localhost';
mysql> flush privileges;

6. 修改字符集为UTF-8

mysql> show variables like 'char%';
mysql> show variables like 'collation%';

sudo vim /etc/mysql/conf.d/mysql.cnf
[mysql]
default-character-set = utf8

sudo vim /etc/mysql/mysql.conf.d/mysqld.cnf
[mysqld]
collation-server = utf8_general_ci
character-set-server = utf8

sudo systemctl restart mysql.service

7. 查看运行状态

sudo systemctl status mysql.service
sudo lsof -i:3306
netstat -ntpl | grep 3306