MariaDB (RDMS)

MariaDB (RDMS)#

Mariadb is a good and mature open source relational database and drop-in replacement for MySQL.

See tests/mariadb for complete template.

Adding mariadb to your app’s docker-compose.yaml#

services:
  # ...
  yourapp-mariadb:
    image: mariadb:11
    pull_policy: missing
    restart: unless-stopped
    environment:
    - MARIADB_DATABASE=mariadb
    - MARIADB_USER=mariadb
    # this should be in your .env file and set to a long random string
    - MARIADB_PASSWORD
    ports:
    - 3306:3306
    volumes:
    - yourapp-mariadb-data:/var/lib/mysql

volumes:
  yourapp-mariadb-data:
    x-kubernetes:
      size: 1Gi
      class: local-path

Transfering your local database to the production database#

# stream dump output directly to pg_restore on db runnning in cluster
docker compose exec -t yourapp-mariadb mariadb-dump mariadb \
  | sshkube run kube-compose exec -i yourapp-mariadb mysql

# you can of course go the other way around as well if you needed to get information from production
sshkube run kube-compose exec -t yourapp-mariadb mariadb-dump mariadb \
  | docker compose exec -i yourapp-mariadb mysql

Accessing the database in your app#

The database will be accessible at the hostname corresponding to your service name, but it’s best practice to set up an environment variable to specify the location. For example, in python:

  • .env:

    # so you can test accessing the database locally
DATABASE_URL=mariadb://mariadb:YOURMARIADB_PASSWORD@localhost:5432/mariadb

  • docker-compose.yaml:

    services:
  yourapp-app:
    environment:
    # so your app container goes to the right location, **NOT localhost**
    - DATABASE_URL=mariadb://mariadb:${MARIADB_PASSWORD}$@yourapp-mariadb:5432/mariadb

  • app.py:

    import os
import dotenv
import mysql.connector

dotenv.load_dotenv()

# connect to db
conn = mysql.connector.connect(os.environ['DATABASE_URL'])

# ... use conn in your app to build queries ...

conn.close()
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