On the RDS console, DB instances are organized in DB clusters. Generally, a MySQL DB cluster contains a primary DB instance, a standby DB instance (if HA is enabled), and up to five read replicas. Figure 1 shows a data model.
To ensure the compatibility between RDS open APIs and OpenStack Trove, services are provided to the public only at the instance level. The relationship between instance-level services and clusters on the WebUI is as follows:
By default, a cluster is created during the instance creation, and the created instance is mounted in this cluster.
All the DB instances to which the user belongs are listed during the DB instance enumeration. The hierarchical relationship between the cluster and the instance is not provided.
The function of deleting a read replica is the same as that on the RDS console, indicating the deletion of the specified DB instance. When you delete primary/standby DB instances, the cluster which the primary/standby DB instances belong to and read replicas will also be deleted.