fchantada/centos-mysql repository overview

⁠Docker Environment Variables

When you create a MySQL Server container, you can configure the MySQL instance by using the --env option (-e in short) and specifying one or more of the following environment variables.

• MYSQL_RANDOM_ROOT_PASSWORD: When this variable is true (which is its default state, unless MYSQL_ROOT_PASSWORD is set or MYSQL_ALLOW_EMPTY_PASSWORD is set to true), a random password for the server's root user is generated when the Docker container is started. The password is printed to stdout of the container and can be found by looking at the container’s log.

• MYSQL_ONETIME_PASSWORD: When the variable is true (which is its default state, unless MYSQL_ROOT_PASSWORD is set or MYSQL_ALLOW_EMPTY_PASSWORD is set to true), the root user's password is set as expired and must be changed before MySQL can be used normally. This variable is only supported for MySQL 5.6 and later.

• MYSQL_DATABASE: This variable allows you to specify the name of a database to be created on image startup. If a user name and a password are supplied with MYSQL_USER and MYSQL_PASSWORD, the user is created and granted superuser access to this database (corresponding to GRANT ALL). The specified database is created by a CREATE DATABASE IF NOT EXIST⁠ statement, so that the variable has no effect if the database already exists.

• MYSQL_USER, MYSQL_PASSWORD: These variables are used in conjunction to create a user and set that user's password, and the user is granted superuser permissions for the database specified by the MYSQL_DATABASE variable. Both MYSQL_USER and MYSQL_PASSWORD are required for a user to be created; if any of the two variables is not set, the other is ignored. If both variables are set but MYSQL_DATABASE is not, the user is created without any privileges.

  Note

  There is no need to use this mechanism to create the root superuser, which is created by default with the password set by either one of the mechanisms discussed in the descriptions for MYSQL_ROOT_PASSWORD and MYSQL_RANDOM_ROOT_PASSWORD, unless MYSQL_ALLOW_EMPTY_PASSWORD is true.

• MYSQL_REPL_USER, MYSQL_REPL_PASSWORD, MYSQL_REPL_ID: These variables are used in conjunction to create replication user and set that user's password, and set Server-Id variable in my.cnf (must be unique). If any of the three variables is not set, the other is ignored. If the three variables are set but MYSQL_REPL_MASTER is not, the host works as master only. If MYSQL_REPL_MASTER is specified, the host works as master-slave.

  Note

  All Databases will be replicated, except mysql and information_schema databases.

• MYSQL_ROOT_HOST: By default, MySQL creates the 'root'@'localhost' account. This account can only be connected to from inside the container. To allow root connections from other hosts, set this environment variable. For example, the value 172.17.0.1, which is the default Docker gateway IP, allows connections from the host machine that runs the container. The option accepts only one entry, but wildcards are allowed (for example, MYSQL_ROOT_HOST=172.*.*.* or MYSQL_ROOT_HOST=%).

• MYSQL_LOG_CONSOLE: When the variable is true (which is its default state for MySQL 8.0 server containers), the MySQL Server's error log is redirected to stderr, so that the error log goes into the Docker container's log and is viewable using the docker logs command.

  Note

  The variable has no effect if a server configuration file from the host has been mounted (see Persisting Data and Configuration Changes⁠ on bind-mounting a configuration file).

• MYSQL_ROOT_PASSWORD: This variable specifies a password that is set for the MySQL root account.

  Warning

  Setting the MySQL root user password on the command line is insecure. As an alternative to specifying the password explicitly, you can set the variable with a container file path for a password file, and then mount a file from your host that contains the password at the container file path. This is still not very secure, as the location of the password file is still exposed. It is preferable to use the default settings of MYSQL_RANDOM_ROOT_PASSWORD and MYSQL_ONETIME_PASSWORD being both true.

• MYSQL_ALLOW_EMPTY_PASSWORD. Set it to true to allow the container to be started with a blank password for the root user.

  Warning

  Setting this variable to true is insecure, because it is going to leave your MySQL instance completely unprotected, allowing anyone to gain complete superuser access. It is preferable to use the default settings of MYSQL_RANDOM_ROOT_PASSWORD and MYSQL_ONETIME_PASSWORD being both true.