Basic Concepts

DDM Instance

A DDM instance is the smallest management unit of DDM. Each DDM instance is an independent database. You can create or modify a DDM instance using the DDM console or API. Then create multiple schemas in the DDM instance and associate each schema with multiple MySQL DB instances. Each MySQL DB instance can be accessed independently.

MySQL DB instances in this document include RDS for MySQL DB instances and GaussDB(for MySQL) DB instances.

VPC

A Virtual Private Cloud (VPC) is a private and isolated virtual network. You can configure IP address ranges, subnets, and security groups, assign EIPs, and allocate bandwidth for DDM instances.

Subnet

A subnet is a range of IP addresses, a logical subdivision of an IP network. Subnets are created for a VPC where you will place your DDM instances. Every subnet is defined by a unique CIDR block which cannot be modified once the subnet is created.

Security Group

A security group is a collection of rules for ECSs that have the same security protection requirements and are mutually trusted. After a security group is created, you can add different access rules to the security group, and these rules will apply to all ECSs added to this security group.

Your account automatically comes with a security group by default. The default security group allows all outbound traffic and denies all inbound traffic. Your ECSs in this security group can communicate with each other without the need to add rules.

Parameter Template

A parameter template acts as a container for configuration values that can be applied to one or more DDM instances. If you want to use your own parameter template, you only need to create a custom parameter template and select it when creating a DDM instance. You can also apply the parameter template to an existing DDM instance.

EIP

The Elastic IP (EIP) service provides independent public IP addresses and bandwidth for Internet access. EIPs can be bound to and unbound from DDM instances.