monasca/mysql-init repository overview

⁠mysql-init Dockerfile

This image runs a set of user-provided scripts to initialize a MySQL database. These are standard .sql scripts that can manage users and databases as well as import schemas.

Sources: mysql-init⁠ · Dockerfile⁠ · monasca-docker⁠

⁠Tags

Images in this repository are tagged as follows:

• latest: refers to the latest stable point release, e.g. 1.0.0
• 1.0.0, 1.0, 1: standard semver tags

⁠Usage

This image requires access to a running MySQL instance. By default it comes with the scripts necessary to initialize a MySQL database for Monasca's Docker⁠ and Kubernetes⁠ environments, but these can be replaced at runtime as described below.

The job is intended to be run only once like so, and requires no persistent storage:

docker run --rm=true monasca/mysql-init:latest

If needed, connection parameters can be provided via environment variables as described below. This script does not make any attempt to prevent re-execution of scripts when run against an already-initialized MySQL instance. There are several methods to account for this:

• Configure your runtime environment to only execute the job once. Kubernetes Jobs⁠ are appropriate for this purpose.
• Design your MySQL scripts to only execute on a clean database, or use constructs like CREATE DATABASE IF NOT EXISTS...
• Use any of the password-changing variables described below to make future login attempts fail

⁠Configuration

While this image requires access (probably root-level) to a MySQL instance at startup, MYSQL_INIT_DISABLE_REMOTE_LOGIN, MYSQL_INIT_RANDOM_PASSWORD, and MYSQL_INIT_CHANGE_PASSWORD may be used to better lock down the container once initialization has completed successfully. These commands will only run if all scripts could be executed successfully.

Notes about password-related variables:

• MYSQL_INIT_DISABLE_REMOTE_LOGIN will remove access from all wildcard hosts to the root account. As such, it requires privileges to modify the mysql.users table.
• MYSQL_INIT_RANDOM_PASSWORD will set the specified user's password to a random value by running pwgen -1 32. It will be written as a line to stdout of the form GENERATED ${MYSQL_INIT_USERNAME} PASSWORD: $(pwgen -1 32)

⁠User scripts

SQL scripts placed in /mysql-init.d/*.sql will be executed on startup using the configured account. Note that no database will be initially selected, so be sure to include USE ... statements as needed.

Scripts are executed in alphabetical order as dictated by shell globbing. To ensure scripts run in a particular order, a naming convention like xx-scriptname.sql is recommended, where xx is two numbers indicating the priority. These will be executed from least (00) to greatest (99).

The container has Monasca-specific scripts included. To use your own, you can mount over the directory with a Docker volume mount:

docker run --rm=true -v /path/to/new/scripts:/mysql-init.d monasca/mysql-init:latest

⁠Templating

SQL scripts may include Jinja2 templates⁠ to, e.g., apply environment configurations like passwords at runtime. To make use of this, append a .j2 to your .sql script, e.g. /mysql-init.d/01-myscript.sql.j2. Templates will be applied at startup before any scripts have been applied to the database.

Templates have access to all environment variables, such as {{ MYSQL_INIT_HOST }}, as well as all built-in Jinja2 filters.