CMDB

**Table 1** Basic concepts of CMDB
Terminology	Description
CMDB	CMDB manages relationships between applications and cloud resources and provides unified and timely resource environment management for AOM monitoring, automatic O&M, and APM.
Application topology	Hierarchical relationships between resources and applications. CMDB uses the "application + sub-application (optional) + component + environment" management model.
Enterprise project	An enterprise project can contain one or more applications.
Application	Basic object of CMDB and root node of the resource management model. An application represents a logical unit, which can be a project, product, or service. After an application is created, you can view the same application topology information in all regions. For example, an online shopping application includes user management, login verification, item list, and order management services.
Sub-application	Optional node for application management. An application can contain up to three layers of sub-applications. A sub-application can be regarded as a service, which is a group of components or microservices.
Component	Minimum unit of an application. It can be regarded as a program or middleware on which an application depends, such as Relational Database Service (RDS) and Distributed Message Service (DMS). Generally, a component is used together with environments. It can contain one or more environments. For example, an order application includes the function test environment, pressure test environment, pre-release environment, and live network environment.
Environment	Used to distinguish different environments or deployment regions of a component. Components or programs with different configurations form different environments. Each environment has its own region attribute. You can filter environments by region. You can also add one or more tags when creating an environment, and filter environments by tag. For example, a formal or test environment.
Environment tag	An attribute set for an environment. Multiple environments may have the same tag. You can filter required environments by tag. A tag can be added only to different environments of the same application.
Resource binding	You can bind a resource object to an environment of an application. A resource object instance of an application can belong to multiple environments.
Resource unbinding	If a component or environment changes and resources are not required, you can unbind them.
Resource transfer	If the component or environment to which a resource is bound changes, transfer the resource to the target node.