AWS Certified SysOps Administrator – Associate (legacy) — Question 793

What would happen to an RDS (Relational Database Service) multi-Availability Zone deployment if the primary DB instance fails?

Answer options

• A. The IP of the primary DB Instance is switched to the standby DB Instance.
• B. A new DB instance is created in the standby availability zone.
• C. The canonical name record (CNAME) is changed from primary to standby.
• D. The RDS (Relational Database Service) DB instance reboots.

Correct answer: C

Explanation

During an RDS (Relational Database Service) Multi-AZ failover, AWS automatically updates the DNS canonical name record (CNAME) of the DB instance to point to the standby DB instance, ensuring a seamless transition without requiring manual IP or application configuration changes. Option A is incorrect because IPs are not swapped; instead, DNS resolution handles the routing. Option B is incorrect because the standby instance is already pre-provisioned, and Option D is incorrect because a simple reboot of the failed primary does not resolve a hardware or AZ-level failure.