Overview

E-commerce applications are used by external customers, require high availability, and should withstand component faults. The availability objective is 99.99%, that is, the annual fault interruption duration should not exceed 52.56 minutes.

Assume that the fault interruption duration and change interruption duration are as follows:

• Fault-caused interruptions: Assume that there are three fault-caused interruptions each year. It takes 10 minutes to decide on the emergency recovery for each interruption and 5 minutes to recover application services. Thus, the total yearly interruption time is 45 minutes.
• Change-caused interruptions: Assume that applications support canary deployment or blue-green deployment, which are automatically completed. Software updates do not interrupt services.

According to the preceding evaluation, the application system is unavailable for 45 minutes every year, meeting the availability design objective.

The typical architecture of an e-commerce application is a stateless application layer at the frontend and databases at the backend. The frontend stateless applications can be deployed on ECSs or CCE instances. The backend databases can be RDS for MySQL or other databases based on service types. Middleware such as DCS and Kafka and DDS databases are also used. The following solutions are recommended to meet the availability objectives.