This topic introduces the reasons why a primary/secondary switchover is triggered for an ApsaraDB RDS for MySQL instance.
A primary/secondary switchover is triggered due to one of the following reasons:
Alibaba Cloud detects vulnerabilities in the RDS instance. The RDS instance may not be able to run as normal due to these vulnerabilities. In this case, ApsaraDB RDS fixes these vulnerabilities in the secondary RDS instance of the RDS instance. Then, ApsaraDB RDS initiates a primary/secondary switchover during the specified maintenance window to switch over your workloads to the secondary RDS instance. For more information, see Set the maintenance window of an ApsaraDB RDS for MySQL instance.
- Manual operations
You or your authorized Alibaba Cloud technical expert manually performs a primary/secondary switchover.
- Instance failures
Alibaba Cloud detects failures in the RDS instance. The RDS instance cannot run as normal due to these failures. In this case, ApsaraDB RDS initiates a primary/secondary switchover to switch over your workloads to the secondary RDS instance of the RDS instance. This minimizes the impacts of the failures.
After a primary/secondary switchover is completed, the status of the RDS instance shows as Running. You do not need to perform other operations, and the RDS instance can run as normal. If you want to view the primary/secondary switchover logs, go to the Primary/Secondary Switching Logs tab of the Logs page in the ApsaraDB RDS console.