Help Center> > API Reference > Before You Start >Concepts


  • Account

    An account is created after you register with the cloud platform. It has full access permissions on its resources and cloud services, such as resetting password and granting permissions. Accounts make payments and should not be used for daily work. They can create users and use the users to manage resources and cloud services.

  • User

    An IAM user is created by an account in IAM to use cloud services. Each IAM user has its own identity credentials (password and access keys).

    An IAM user can view the account ID and user ID on the My Credentials page of the management console. API authentication requires information such as the account name, username, and password.

  • Region

    A region is a geographic area in which cloud resources are deployed. Availability zones (AZs) in the same region can communicate with each other over an intranet, while AZs in different regions are isolated from each other. Deploying cloud resources in different regions can better suit certain user requirements or comply with local laws or regulations.

  • AZ

    An AZ comprises of one or multiple physical data centers equipped with independent ventilation, fire, water, and electricity facilities. Computing, network, storage, and other resources in an AZ are logically divided into multiple clusters. AZs within a region are interconnected using high-speed optical fibers to allow you to build cross-AZ high-availability systems.

  • Project

    A project corresponds to a region. Default projects are defined to a group and have physically isolated resources (including computing, storage, and network resources) across regions. Users can be granted permissions in a default project to access all resources in the region associated with the project. If you need more refined access control, you can create subprojects under a default project and purchase resources in subprojects. Then you can assign required permissions for users to access only the resources in specific subprojects.

    Figure 1 Project isolating model
  • Checkpoint: When an application consumes data, the latest SN of the consumed data is recorded as a checkpoint. When the data is reconsumed, the consumption can be continued based on this checkpoint.
  • APP: Multiple applications can access data in the same stream. Checkpoints generated for each application are used to record the consumed data in the stream by each application.