Docker MySQL 8 how to set --secure-file-priv

According to this documentation, you can configure secure-file-priv through command-line by passing --secure-file-priv=dir_name

secure-file-priv possible values are: empty string, dirname or NULL as explained in the privous url.

From mysql-docker page:

Configuration without a cnf file: Many configuration options can be passed as flags to mysqld. This will give you the flexibility to customize the container without needing a cnf file. For example, if you want to change the default encoding and collation for all tables to use UTF-8 (utf8mb4) just run the following:

$ docker run --name some-mysql -e MYSQL_ROOT_PASSWORD=my-secret-pw -d mysql:tag --character-set-server=utf8mb4 --collation-server=utf8mb4_unicode_ci

So in our case would be like this:

dir_name should be a directory inside your container otherwise you will get the following error: mysqld: Error on realpath() on 'dir_name' (Error 2 - No such file or directory)

$ docker run --name some-mysql -e MYSQL_ROOT_PASSWORD=my-secret-pw -d mysql:tag --secure-file-priv=dir_name

And now our change is committed in MySQL

mysql> SHOW VARIABLES LIKE "secure_file_priv";+------------------+----------+| Variable_name    | Value    |+------------------+----------+| secure_file_priv | dir_name |+------------------+----------+

Alternatively, you can use a custom configuration file as explained in here:

Using a custom MySQL configuration file: The default configuration for MySQL can be found in /etc/mysql/my.cnf, which may !includedir additional directories such as /etc/mysql/conf.d or /etc/mysql/mysql.conf.d. Please inspect the relevant files and directories within the mysql image itself for more details.

If /my/custom/config-file.cnf is the path and name of your custom configuration file, you can start your mysql container like this (note that only the directory path of the custom config file is used in this command):

$ docker run --name some-mysql -v /my/custom:/etc/mysql/conf.d -e MYSQL_ROOT_PASSWORD=my-secret-pw -d mysql:tag

This will start a new container some-mysql where the MySQL instance uses the combined startup settings from /etc/mysql/my.cnf and /etc/mysql/conf.d/config-file.cnf, with settings from the latter taking precedence.