DBS-C01 Management and Operations Practice Question
A company is running an Amazon RDS for PostgreSQL DB instance with Multi-AZ. The database experiences a failover during a maintenance window. After the failover, the application connection pool continues to use the old primary endpoint, causing connection errors. What is the BEST way to ensure application connections automatically redirect to the new primary after a failover?
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Use the RDS endpoint (CNAME) provided by RDS, which automatically points to the primary instance.
The RDS endpoint (CNAME) provided by Amazon RDS automatically points to the current primary instance. After a failover, RDS updates the CNAME record to point to the new primary, so application connections using the endpoint are seamlessly redirected without manual intervention. This is the simplest and most reliable approach. Option B (Custom Route 53 failover routing) is unnecessary because RDS already provides a managed DNS endpoint. Option C (modifying connection string manually) is not automated and prone to human error. Option D (static IP) is not practical as RDS instances do not have static IPs; the DNS endpoint handles failover transparently.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Use the RDS endpoint (CNAME) provided by RDS, which automatically points to the primary instance.
Why this is correct
The RDS endpoint is a DNS CNAME that updates after failover, ensuring seamless redirection.
- ✗
Create a custom Route 53 failover routing policy pointing to both DB instances.
Why it's wrong here
Custom DNS adds complexity; RDS already provides a CNAME that updates automatically.
- ✗
Modify the application connection string to point to the new primary IP address after each failover.
Why it's wrong here
Manual modification is not automated and leads to errors.
- ✗
Configure the application to use a static IP address of the primary instance.
Why it's wrong here
Static IP is not recommended because the IP can change after failover.
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Same concept, more angles
1 more way this is tested on DBS-C01
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. A company runs a production Amazon RDS for MySQL Multi-AZ DB instance. The database experiences a failover event. After the failover, the application team reports increased latency for write operations. Which action should be taken to investigate the issue?
medium- A.Increase the allocated storage for the DB instance to reduce I/O contention.
- B.Enable automated backups and configure a backup window.
- ✓ C.Verify that the application is using the correct DB endpoint and that DNS has propagated.
- D.Modify the DB instance to a larger instance class to improve write performance.
Why C: After a failover, the DNS record updates to point to the new primary. If DNS has not propagated, the application may be connecting to the old primary or experiencing routing issues, leading to increased write latency. Verifying DNS resolution ensures the application is using the correct endpoint. Option A is incorrect because increasing storage does not directly address latency caused by DNS propagation; it might help with I/O contention under normal conditions, but it is not the appropriate first step for investigating post-failover latency. Option B is incorrect because automated backups do not impact write latency; they run in the background and do not interfere with database operations. Option D is incorrect because changing the instance class can improve performance, but the immediate issue after failover is likely DNS propagation, not insufficient compute capacity.
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This DBS-C01 practice question is part of Courseiva's free Amazon Web Services certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the DBS-C01 exam.