Interfaces/endpoints

Charmed MySQL VM supports modern mysql_client and legacy mysql, mysql-shared, mysql-router interfaces (in a backward compatible mode).

Note: do NOT relate both modern and legacy interfaces simultaneously.

Modern relations

This charm provides modern ‘mysql_client’ interface. Applications can easily connect MySQL using ‘data_interfaces’ library from ‘data-platform-libs’.

Modern mysql_client interface (database endpoint):

Adding a relation is accomplished with juju relate (or juju integrate for Juju 3.x) via endpoint database. Read more about Juju relations (integrations). Example:

# Deploy Charmed MySQL cluster with 3 nodes
juju deploy mysql -n 3 --channel 8.0

# Deploy the relevant charms, e.g. mysql-test-app
juju deploy mysql-test-app

# Relate MySQL with your application
juju relate mysql:database mysql-test-app:database

# Check established relation (using mysql_client interface):
juju status --relations

# Example of the properly established relation:
# > Relation provider   Requirer                 Interface     Type
# > mysql:database      mysql-test-app:database  mysql_client  regular

Note: In order to relate with this charm, every table created by the related application must have a primary key. This is required by the group replication plugin enabled in this charm.

Legacy relations

Note: Legacy relations are deprecated and will be discontinued on future releases. Usage should be avoided.

This charm supports several legacy interfaces, e.g. mysql, mysql-shared, mysql-router. They were used in some legacy charms in cross-model relations.

mysql interface (mysql endpoint)

It was a popular interface used by some legacy charms (e.g. “MariaDB”, “OSM MariaDB”, “Percona Cluster” and “Mysql Innodb Cluster”), often in cross-model relations:

juju deploy mysql --channel 8.0
juju config mysql mysql-interface-database=mediawiki mysql-interface-user=mediawiki
juju deploy mediawiki
juju relate mysql:mysql mediawiki:db

mysql-router interface (db-router endpoint)

It is a relation that one uses with the mysql router charm. The following commands can be executed to deploy and relate to the keystone charm:

juju deploy mysql --channel 8.0
juju deploy mysql-router --series focal
juju deploy keystone --series focal
juju relate mysql-router keystone
juju relate mysql:db-router mysql-router:db-router

Note: pay attention to deploy identical series for keystone and mysql-router applications (due to the subordinate charm nature of mysql-router).

mysql-shared interface (shared-db endpoint)

It is a relation that one uses when the application needs to connect directly to the database cluster. It is supported by various legacy charms, e.g. mysql-innodb-cluster. The following commands can be executed to deploy and relate to the keystone charm:

juju deploy mysql --channel 8.0
juju deploy keystone --series focal
juju relate keystone:shared-db mysql:shared-db