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一、安装

参考：

• 
  安装 mysql8.0.13 （Ubuntu 16.04 desktop amd64）
  
• 
  客户端连接MySQL(8.0)出错(caching_sha2_password)
  
• 
  远程连接MYSQL提示Host is not allowed to connect to this MySQL server
  

1、下载mysql deb：https://dev.mysql.com/downloads/mysql/

2、移动到/usr/local/src/目录，解压

sudo mv mysql-server_8.0.13-1ubuntu16.04_amd64.deb-bundle.tar /usr/local/src/
cd /usr/local/src/
sudo tar -xvf mysql-server_8.0.13-1ubuntu16.04_amd64.deb-bundle.tar

3、更新，安装依赖

sudo apt-get update
sudo apt-get install libaio1

4、安装MySQL

sudo dpkg -i mysql-common_8.0.13-1ubuntu16.04_amd64.deb
sudo dpkg-preconfigure mysql-community-server-core_8.0.13-1ubuntu16.04_amd64.deb
sudo dpkg -i libmysqlclient21_8.0.13-1ubuntu16.04_amd64.deb
sudo dpkg -i libmysqlclient-dev_8.0.13-1ubuntu16.04_amd64.deb
sudo dpkg -i mysql-community-client-core_8.0.13-1ubuntu16.04_amd64.deb
sudo dpkg -i mysql-community-client_8.0.13-1ubuntu16.04_amd64.deb
sudo dpkg -i mysql-client_8.0.13-1ubuntu16.04_amd64.deb
sudo apt-get -f install
sudo apt-get -f install libmecab2
sudo dpkg -i mysql-community-server-core_8.0.13-1ubuntu16.04_amd64.deb
sudo dpkg -i mysql-community-server_8.0.13-1ubuntu16.04_amd64.deb

5、进入MySQL

mysql -u root -p

sudo service mysql start     # 启动
sudo  service mysql restart  # 重启
sudo service mysql stop      # 关闭
sudo service mysql status    # 检查mysql是否在运行

二、两个常见报错

安装完成之后常会见到以下两个错误：

1. Host is not allowed to connect to this MySQL server
2. Authentication plugin ‘caching_sha2_password’ cannot be loaded

正常情况的话，会先遇到第一个，再遇到第二个；解决第一个后，再解决第二个时，需要把第一个做的改动改回去才行，所以建议先解决第二个报错。

进入 mysql

mysql -u root -p

mysql>use mysql;
mysql>select host,user,plugin from user;

解决 Authentication plugin ‘caching_sha2_password’ cannot be loaded（还原加密规则）

mysql> ALTER USER 'root'@'localhost' IDENTIFIED BY '123456' PASSWORD EXPIRE NEVER; 
mysql> ALTER USER 'root'@'localhost' IDENTIFIED WITH mysql_native_password BY '123456';
mysql>select host,user,plugin from user;

上面的mysql登录状态不要退出，接着……

解决 Host is not allowed to connect to this MySQL server（改表法）

mysql>update user set host = '%' where user = 'root';
mysql>select host,user,plugin from user;

最后刷新权限退出

mysql>flush privileges;
mysql>exit