Installing MySQL 8 on Debian 12 with a Mirror Repository

On Debian 12, installing the latest MySQL 8 through a mirror can be more convenient than using the default repository setup. The process mainly involves adding the mirror source, importing the GPG key, removing conflicting MariaDB packages, and then adjusting a few MySQL settings after installation.

Installation

Add the MySQL APT source from the mirror, install GnuPG, import the signing key, clean out MariaDB-related packages, and then install MySQL:

<table> <thead> <tr> <th>1 2 3 4 5 6 7 8</th> <th>echo deb https://mirrors.tuna.tsinghua.edu.cn/mysql/apt/debian bookworm mysql-8.0 mysql-tools > /etc/apt/sources.list.d/mysql-community.list # 添加清华镜像源 apt install -y gnupg # 安装gpg apt-key adv --keyserver pgp.mit.edu --recv-keys A8D3785C # 导入gpg密钥 # apt-key adv --keyserver keyserver.ubuntu.com --recv-keys A8D3785C # 上一条命令导入失败则选择此命令 apt-key export A8D3785C | sudo gpg --dearmour -o /etc/apt/trusted.gpg.d/mysql.gpg # 导出密钥，避免更新警告 sudo apt remove --purge mariadb-client-core mariadb-server-core libmariadb3 mariadb-common # 卸载MariaDB apt auto-remove # 自动卸载无用依赖 apt update && apt install mysql-community-server # 安装MySQL</th> </tr> </thead> <tbody> <tr> <td></td> <td></td> </tr> </tbody> </table>

During setup, you will be prompted to create a password for the MySQL root account:

You will then need to enter it again for confirmation:

Next, the installer asks which authentication plugin to use. For easier client connections, the second option is generally the more practical choice:

In MySQL 8.0 and later, the root account uses the auth_socket plugin by default. That behavior has several consequences:

1. root can log in only locally through 127.0.0.1; remote machines cannot use the root account.
2. Logging in as MySQL root requires using the operating system's root account. Users who cannot elevate with sudo are blocked.
3. No password is required. Even if a password is manually assigned to root, it will not be checked during login.

If you choose the second authentication option during installation, MySQL writes the following setting into /etc/mysql/mysql.conf.d/default-auth-override.cnf:

default-authentication-plugin = mysql_native_password

If that line is commented out later, newly created users will go back to using auth_socket by default. To inspect which authentication plugin each account is using, run:

SELECT user,host,plugin FROM mysql.user;

To change an account's authentication plugin manually, you can use a statement like this:

ALTER USER 'root'@'%' IDENTIFIED WITH caching_sha2_password BY '新密码';

Basic configuration

Edit /etc/mysql/mysql.conf.d/mysqld.cnf with the following commands:

<table> <thead> <tr> <th>1 2 3 4 5 6</th> <th>cat >> /etc/mysql/mysql.conf.d/mysqld.cnf << EOF bind-address = 0.0.0.0 port = 3306 skip-ssl EOF systemctl restart mysql</th> </tr> </thead> <tbody> <tr> <td></td> <td></td> </tr> </tbody> </table>

These options are meant to make the server behavior explicit:

• bind-address = 0.0.0.0
• port = 3306

Although MySQL already listens on 0.0.0.0:3306 by default, keeping these lines in the configuration makes the intended network behavior clear and easier to adjust later.

The skip-ssl option disables SSL. Without disabling it, the MySQL client may fail certificate verification because the server uses a self-signed certificate by default. In that case, connections only work if the client is started with --ssl-mode=DISABLED each time.

To check whether SSL is enabled, run:

SHOW VARIABLES LIKE 'ssl';

If have_ssl shows DISABLED, then SSL is off.

Connecting to MySQL

After the service restarts, connect and verify the version:

<table> <thead> <tr> <th>1 2</th> <th>mysql -u root -p select version();</th> </tr> </thead> <tbody> <tr> <td></td> <td></td> </tr> </tbody> </table>

Allowing root to connect from any host

If you need the root account to be reachable from any host, update its host field in the MySQL system table:

<table> <thead> <tr> <th>1 2</th> <th>UPDATE mysql.user SET host='%' WHERE user='root'; -- 修改root用户的主机访问权限为允许从任何主机连接 select user,host from mysql.user; # 查看所有用户的主机访问权限</th> </tr> </thead> <tbody> <tr> <td></td> <td></td> </tr> </tbody> </table>

This changes root so it is no longer limited to local access, and the second query lets you verify the host permissions for all users.