source
Parameters
If you want to create a read replica DB instance, specify the ID of the source DB instance. Each DB instance can have a limited number of read replicas. For more information, see Working with Read Replicas in the Amazon RDS User Guide. For information about constraints that apply to DB instance identifiers, see Naming constraints in Amazon RDS in the Amazon RDS User Guide. The `SourceDBInstanceIdentifier` property determines whether a DB instance is a read replica. If you remove the `SourceDBInstanceIdentifier` property from your template and then update your stack, AWS CloudFormation promotes the read replica to a standalone DB instance. If you specify the `UseLatestRestorableTime` or `RestoreTime` properties in conjunction with the `SourceDBInstanceIdentifier` property, RDS restores the DB instance to the requested point in time, thereby creating a new DB instance. + If you specify a source DB instance that uses VPC security groups, we recommend that you specify the `VPCSecurityGroups` property. If you don't specify the property, the read replica inherits the value of the `VPCSecurityGroups` property from the source DB when you create the replica. However, if you update the stack, AWS CloudFormation reverts the replica's `VPCSecurityGroups` property to the default value because it's not defined in the stack's template. This change might cause unexpected issues.
Read replicas don't support deletion policies. AWS CloudFormation ignores any deletion policy that's associated with a read replica.
If you specify
`SourceDBInstanceIdentifier`, don't specify the`DBSnapshotIdentifier`property. You can't create a read replica from a snapshot.Don't set the
`BackupRetentionPeriod`,`DBName`,`MasterUsername`,`MasterUserPassword`, and`PreferredBackupWindow`properties. The database attributes are inherited from the source DB instance, and backups are disabled for read replicas.If the source DB instance is in a different region than the read replica, specify the source region in
`SourceRegion`, and specify an ARN for a valid DB instance in`SourceDBInstanceIdentifier`. For more information, see Constructing a Amazon RDS Amazon Resource Name (ARN) in the Amazon RDS User Guide.For DB instances in Amazon Aurora clusters, don't specify this property. Amazon RDS automatically assigns writer and reader DB instances.