Docker-compose script for simple data migration from MySQL 8.0 to MariaDB

[an3l]

• First commit structuralizes previous example
• To test the PR run following:

  $ sudo rm -rf dump-data/ && mkdir dump-data && sudo chown -R 999:999 dump-data
  $ docker compose -f compose-mysql8.0.yml down -v
  [+] Running 2/0
  ✔ Volume migration-80_mysqldump  Removed                                                                                                                                                                  0.0s 
  ✔ Volume migration-80_dbdata     Removed 
  $ docker compose -f compose-mysql8.0.yml up

• Check containers

  $ docker ps
  CONTAINER ID   IMAGE          COMMAND                  CREATED              STATUS                          PORTS                 NAMES
  cbcdd1450304   mariadb:lts    "docker-entrypoint.s…"   About a minute ago   Up About a minute (healthy)     3306/tcp              mariadb-migrated-mysql8.0
  a3c6dd61ad5c   mariadb:lts    "docker-entrypoint.s…"   About a minute ago   Up About a minute (healthy)     3306/tcp              mariadb-container-dump
  cc8c028ddca4   mysql:8.3.0    "docker-entrypoint.s…"   About a minute ago   Up About a minute (healthy)     3306/tcp, 33060/tcp   mysql-container

• Check logs during services startup

  
  # Dumping files
  mariadb-container-dump     | 2024-02-19 13:13:12+00:00 [Note] [Entrypoint]: /usr/local/bin/docker-entrypoint.sh: running /docker-entrypoint-initdb.d/dump-mysql.sh
  mariadb-container-dump     | MariaDB service started.
  mariadb-container-dump     | mysql
  mariadb-container-dump     | Remove files if exist
  mariadb-container-dump     | Dump and compress MySQL data with changed collation ...
  mariadb-container-dump     | Dump and compress MySQL users ...
  mariadb-container-dump     | Dump and compress MySQL stats ...
  mariadb-container-dump     | Dump and compress MySQL timezones 

Migrated container

mariadb-migrated-mysql8.0 | 2024-02-19 13:13:33+00:00 [Note] [Entrypoint]: /usr/local/bin/docker-entrypoint.sh: sourcing /docker-entrypoint-initdb.d/migrate-mariadb.sh mariadb-migrated-mysql8.0 | Extract file /etc/dump/mysql-dump-data.sql.zst: 1894 bytes
mariadb-migrated-mysql8.0 | Show data in MariaDB mariadb-migrated-mysql8.0 | Database mariadb-migrated-mysql8.0 | information_schema mariadb-migrated-mysql8.0 | mysql mariadb-migrated-mysql8.0 | performance_schema mariadb-migrated-mysql8.0 | sys mariadb-migrated-mysql8.0 | testdb mariadb-migrated-mysql8.0 | name mariadb-migrated-mysql8.0 | Bosnia & Herzegovina

- Or if one wants to check on CLI
```bash
# Source of data MySQL 8.0
$ docker exec -it mysql-container mysql -uroot -psecret -e "select * from testdb.countries"
mysql: [Warning] Using a password on the command line interface can be insecure.
+----------------------+
| name                 |
+----------------------+
| Bosnia & Herzegovina |
+----------------------+

# Migrated data to MariaDB
$ docker exec -it mariadb-migrated-mysql8.0 mariadb -uroot -psecret -e "select * from testdb.countries"
+----------------------+
| name                 |
+----------------------+
| Bosnia & Herzegovina |
+----------------------+