Microcluster uses the distributed database dqlite to persist and replicate state information across all cluster members.
All related database files are stored in the /database directory in the Microcluster state directory. A single database is used for both internal Microcluster data and application data.
By default, Microcluster offers 3 tables:
core_cluster_members: Current members of the cluster.core_token_records: Currently active join token secrets and their associated joiner names.schemas: Record of the currently active schema version of the cluster.
The table name prefix core_ is considered reserved for internal data, and any supplied extensions to the schema should not create any tables prefixed with core_.
It is safe to make foreign key references to these tables. Such references will be preserved should these tables encounter internal schema changes.
For information about schema updates, refer to upgrades.md.