Fedora 36启用systemctl服务后无法运行mysqld的问题

问题现象 #

无法运行mysqld，socket连接正常，但配置文件创建存在问题。不同用户执行mysqld时报错如下：

普通用户执行报错 #

joy@fedora /]$ mysqld
2022-11-12 12:38:24 0 [Note] mysqld (mysqld 10.5.16-MariaDB) starting as process 4650 ...

2022-11-12 12:38:24 0 [Warning] Can't create test file /var/lib/mysql/fedora.lower-test

mysqld: Can't create file '/var/log/mariadb/mariadb.log' (errno: 13 "Permission denied")

2022-11-12 12:38:24 0 [ERROR] mysqld: File '/var/lib/mysql/aria_log_control' not found (Errcode: 13 "Permission denied")

2022-11-12 12:38:24 0 [ERROR] mysqld: Got error 'Can't open file' when trying to use aria control file '/var/lib/mysql/aria_log_control'

2022-11-12 12:38:24 0 [ERROR] Plugin 'Aria' init function returned error.

2022-11-12 12:38:24 0 [ERROR] Plugin 'Aria' registration as a STORAGE ENGINE failed.

2022-11-12 12:38:24 0 [ERROR] InnoDB: The innodb_system data file 'ibdata1' must be writable

2022-11-12 12:38:24 0 [ERROR] InnoDB: The innodb_system data file 'ibdata1' must be writable

2022-11-12 12:38:24 0 [ERROR] Plugin 'InnoDB' init function returned error.

2022-11-12 12:38:24 0 [ERROR] Plugin 'InnoDB' registration as a STORAGE ENGINE failed.

2022-11-12 12:38:24 0 [Note] Plugin 'FEEDBACK' is disabled.

2022-11-12 12:38:24 0 [ERROR] Could not open mysql.plugin table: "Table 'mysql.plugin' doesn't exist". Some plugins may be not loaded

2022-11-12 12:38:24 0 [ERROR] Failed to initialize plugins.

2022-11-12 12:38:24 0 [ERROR] Aborting

超级用户执行报错 #

[joy@fedora /]$ sudo mysqld

2022-11-12 12:41:13 0 [Note] mysqld (mysqld 10.5.16-MariaDB) starting as process 4679 ...

mysqld: Please consult the Knowledge Base to find out how to run mysqld as root!

2022-11-12 12:41:13 0 [ERROR] Aborting

解决步骤 #

1. 使用系统服务管理启动MariaDB
   不要直接用普通用户或root运行mysqld，Linux发行版中MariaDB默认通过系统服务运行，自动切换到专用的mysql用户：

   sudo systemctl start mariadb
   

2. 修复权限问题
   报错核心是普通用户无权限访问MariaDB的数据目录和日志目录，执行以下命令修正权限：

   sudo chown -R mysql:mysql /var/lib/mysql
   sudo chown -R mysql:mysql /var/log/mariadb
   sudo chmod 750 /var/lib/mysql
   sudo chmod 750 /var/log/mariadb
   

3. 初始化数据库（首次安装时需要）
   如果是新安装未初始化数据库，执行初始化命令：

   sudo mysql_install_db --user=mysql --datadir=/var/lib/mysql
   

4. 设置开机自启（可选）
   让MariaDB随系统启动：

   sudo systemctl enable mariadb
   

说明 #

MariaDB禁止root直接运行mysqld是出于安全考虑，专用的mysql用户拥有最小必要权限，避免权限过大带来的风险。

内容的提问来源于stack exchange，提问作者softwareplay