Glossary

Regions and AZs

A region and availability zone (AZ) identify the location of a data center. Created resources have a specific region and AZ.

• Regions have their own geographical location and network latency. Public services, such as Elastic Cloud Server (ECS), Elastic Volume Service (EVS), Object Storage Service (OBS), Virtual Private Cloud (VPC), Elastic IP (EIP), and Image Management Service (IMS), are shared in the same region. Regions are either universal or dedicated: universal region provides universal cloud services for common domains while a dedicated region provides services of the same type only or for specific domains.
• An AZ contains one or more physical data centers. Each AZ has independent cooling, fire extinguishing, moisture-proof, and electricity facilities. An AZ's computing, network, storage, and other resources are logically divided into multiple clusters. AZs within a region are interconnected by high-speed optical fibers for building cross-AZ high-availability systems.

Figure 1 shows the relationship between regions and AZs. For details about how to select regions and AZs, see Region and AZ.

Figure 1 Regions and AZs

Environment

Environments distinguish service deployment scenarios and means isolation. In CAE, development, test, pre-production, and production environments are tailored to requirements. Networks in an environment intercommunicate, while components and services are managed and deployed within the environment for easier O&M, production, and rollout.

Application

An application is a service system with functions and consists of one or more application components.

Application Component

An application component implements a service feature of an application. It is in the form of code or software package and can be deployed independently.

Component Instance

An instance is the minimum running and deployment unit of a component, and tends to be used for a single application process.

Serverless

Serverless computing is a model of cloud computing. The cloud provider allocates machine resources on demand and manages servers on behalf of the customers, who are not involved in capacity planning, configuration, management, maintenance, fault tolerance, or scaling of containers, VMs, or physical servers.

Data Redundancy Policy

The two data redundancy policies are multi-AZ storage and single-AZ storage. CAE only supports authorization and creation of object storage with policy multi-AZ storage.

• Multi-AZ storage: Data is stored in multiple AZs in the same region for better availability. A file system created in multi-AZ mode stores its data in three different AZs in the same region. This enables data access in case of unavailability of any single AZ, so the multi-AZ mode is useful for storing data that must always be available.
• Single-AZ storage: Data is stored in a single AZ, with lower costs.