使用docker-compose安装mysql的时候，我挂了一个my.cnf的配置卷，出现了这个错误：

mysql    | 2022-04-02 20:16:59+08:00 [Note] [Entrypoint]: Entrypoint script for MySQL Server 8.0.21-1debian10 started.
mysql    | 2022-04-02 20:16:59+08:00 [Note] [Entrypoint]: Switching to dedicated user 'mysql'
mysql    | 2022-04-02 20:16:59+08:00 [Note] [Entrypoint]: Entrypoint script for MySQL Server 8.0.21-1debian10 started.
mysql    | mysqld: [Warning] World-writable config file '/etc/mysql/my.cnf' is ignored.
mysql    | mysqld: Error on realpath() on '/var/lib/mysql-files' (Error 2 - No such file or directory)
mysql    | 2022-04-02T12:17:00.249816Z 0 [ERROR] [MY-010095] [Server] Failed to access directory for --secure-file-priv. Please make sure that directory exists and is accessible by MySQL Server. Supplied value : /var/lib/mysql-files
mysql    | 2022-04-02T12:17:00.249853Z 0 [ERROR] [MY-010119] [Server] Aborting
mysql    | 2022-04-02 20:17:00+08:00 [Note] [Entrypoint]: Switching to dedicated user 'mysql'
mysql    | 2022-04-02 20:17:00+08:00 [Note] [Entrypoint]: Entrypoint script for MySQL Server 8.0.21-1debian10 started.
mysql    | mysqld: [Warning] World-writable config file '/etc/mysql/my.cnf' is ignored.
mysql    | mysqld: Error on realpath() on '/var/lib/mysql-files' (Error 2 - No such file or directory)
mysql    | 2022-04-02T12:17:01.281919Z 0 [ERROR] [MY-010095] [Server] Failed to access directory for --secure-file-priv. Please make sure that directory exists and is accessible by MySQL Server. Supplied value : /var/lib/mysql-files
mysql    | 2022-04-02T12:17:01.281950Z 0 [ERROR] [MY-010119] [Server] Aborting

是因为权限过高，mysql给你拦截了，不让你这么操作。

解决方法：

进入docker-compose.yml所在目录（或者my.cnf所在目录），在宿主机执行：

chmod 644 my.cnf 

来降低一下权限。

贴上本人的docker-compose.yml

version: '3.3'
services:
  mysql:
    image: mysql:8.0.21
    container_name: mysql
    privileged: true
    command:
      --default-authentication-plugin=mysql_native_password
      --character-set-server=utf8mb4
      --collation-server=utf8mb4_general_ci
    restart: always
    volumes:
      - /etc/localtime:/etc/localtime
      - /data/install-docker-compose/mysql/data:/var/lib/mysql
      - /data/install-docker-compose/mysql/conf:/etc/mysql/conf.d
      - /data/install-docker-compose/mysql/mysql/logs:/logs
      - /data/install-docker-compose/mysql/my.cnf:/etc/mysql/my.cnf
    ports:
      - 3306:3306
    environment:
      MYSQL_ROOT_PASSWORD: mypass123456
      MYSQL_USER: usr2020
      MYSQL_PASSWORD: mypass123456

my.cnf

[mysqld]
pid-file        = /var/run/mysqld/mysqld.pid
socket          = /var/run/mysqld/mysqld.sock
datadir         = /var/lib/mysql
secure-file-priv= /var/lib/mysql
max-connections=9999

# Custom config should go here
!includedir /etc/mysql/conf.d/

目录结构：

其中conf、data、mysql三个文件夹是自动创建的。