【MySQL】在centos7 纯IPv6环境下，安装mysql5.7

参考链接：https://mirrors6.tuna.tsinghua.edu.cn/help/mysql/

服务器环境：
Centos7
纯IPv6环境（不能与IPv4互通）

1. 按照 https://mirrors6.tuna.tsinghua.edu.cn/help/mysql/ 步骤操作完成

2. 执行 yum install mysql-community-server 发现默认安装 mysql 8.0，

   问题：提示找不到签名，因为https://repo.mysql.com/ 只有v4地址，估将https://repo.mysql.com/RPM-GPG-KEY-mysql 下载至 /root 目录下，

3. 修改 /etc/yum.repos.d/mysql-community.repo

[mysql-connectors-community]
name=MySQL Connectors Community
baseurl=https://mirrors.tuna.tsinghua.edu.cn/mysql/yum/mysql-connectors-community-el7-$basearch/
enabled=1
gpgcheck=1
gpgkey=https://repo.mysql.com/RPM-GPG-KEY-mysql

[mysql-tools-community]
name=MySQL Tools Community
baseurl=https://mirrors.tuna.tsinghua.edu.cn/mysql/yum/mysql-tools-community-el7-$basearch/
enabled=1
gpgcheck=1
gpgkey=https://repo.mysql.com/RPM-GPG-KEY-mysql

[mysql-5.6-community]
name=MySQL 5.6 Community Server
baseurl=https://mirrors.tuna.tsinghua.edu.cn/mysql/yum/mysql-5.6-community-el7-$basearch/
enabled=0
gpgcheck=1
gpgkey=https://repo.mysql.com/RPM-GPG-KEY-mysql

[mysql-5.7-community]
name=MySQL 5.7 Community Server
baseurl=https://mirrors.tuna.tsinghua.edu.cn/mysql/yum/mysql-5.7-community-el7-$basearch/
enabled=1
gpgcheck=1
gpgkey=file:///root/RPM-GPG-KEY-mysql
#gpgkey=https://repo.mysql.com/RPM-GPG-KEY-mysql

# 注释 8.0
#[mysql-8.0-community]
#name=MySQL 8.0 Community Server
#baseurl=https://mirrors.tuna.tsinghua.edu.cn/mysql/yum/mysql-8.0-community-el7-$basearch/
#enabled=1
#gpgcheck=1
#gpgkey=https://repo.mysql.com/RPM-GPG-KEY-mysql

4. 再次执行 yum install mysql-community-server 成功安装

5. 启动mysql服务 systemctl start mysqld

6. 进入 mysql mysql -u root -p ，回车

问题：需要密码，从安装到启动服务，也没有设置过密码啊，故更改配置，免密登录

7. 更改配置文件/etc/my.cnf

[mysqld]
skip-grant-tables

8. 启动mysql服务 systemctl restart mysqld

9. 再次执行 mysql -u root -p ，回车成功进入，更改root 密码

update mysql.user set authentication_string=PASSWORD('xxx') where user='root' and host='localhost';
flush privileges;

exit;

9. 关闭 免密登录，即 注释 skip-grant-tables （第7步），重启mysql

10. 测试登录 mysql -u root -p

11. 结束安装