Automating RDS Start/Stop with Least Overhead

SAA-C03 By islever Editorial Last updated

Design cost-optimized compute solutions.

Short answer

D Create an Amazon EventBridge rule that invokes AWS Lambda functions to start and stop the RDS instances.

Question

A company has multiple Amazon RDS DB instances that run in a development AWS account. All the instances have tags to identify them as development resources. The company needs the development DB instances to run on a schedule only during business hours. Which solution will meet these requirements with the LEAST operational overhead?
  1. Create an Amazon CloudWatch alarm to identify RDS instances that need to be stopped. Create an AWS Lambda function to start and stop the RDS instances.
  2. Create an AWS Trusted Advisor report to identify RDS instances to be started and stopped. Create an AWS Lambda function to start and stop the RDS instances.
  3. Create AWS Systems Manager State Manager associations to start and stop the RDS instances.
  4. Create an Amazon EventBridge rule that invokes AWS Lambda functions to start and stop the RDS instances. Correct Answer

Key Takeaways

The question tests the distinction between configuration management (State Manager) and event-driven automation (EventBridge), highlighting that managed runbooks in State Manager do not inherently solve the scheduling requirement without additional complex setup compared to direct cron-based triggers.

This page analyzes the most cost-effective and low-overhead method to schedule Amazon RDS instance start and stop operations using AWS native services. It establishes that EventBridge and Lambda offer a simpler operational model than Systems Manager State Manager for this specific use case.

Common mistake: Many learners select Option C (Systems Manager State Manager) because they assume AWS-managed documents simplify the process, overlooking that State Manager is primarily for compliance/configuration drift rather than simple scheduled lifecycle events, leading to unnecessary complexity.

Expert Analysis

Why the Answer Is Correct

Option D is the correct answer because Amazon EventBridge provides a native, serverless scheduler (Cron or Rate expressions) that can directly invoke AWS Lambda functions. This combination allows you to write simple code to start or stop RDS instances based on tags (e.g., 'Environment=Development') with zero infrastructure management. The operational overhead is minimal as you only maintain the Lambda logic and the rule.

Why the Other Options Are Wrong

Option A uses CloudWatch Alarms, which are designed for metric thresholds (like CPU utilization), not calendar-based schedules, making them inappropriate for time-of-day actions. Option B relies on Trusted Advisor, which is a reporting tool for recommendations and cannot trigger automated actions. Option C suggests using Systems Manager State Manager; while it has RDS runbooks, State Manager is designed for enforcing desired configurations (compliance) rather than simple scheduled start/stop tasks. Using it for this purpose requires defining associations and potentially custom automation documents, which introduces more operational overhead than a simple EventBridge rule.

Community Comment Notes

The community is split, but the majority favors D. User KaZimirovich noted that State Manager is "more complex to set up for straightforward use cases" like scheduling. User bujuman pointed out that State Manager has limitations depending on the DB engine and referenced an AWS blog post recommending EventBridge/Lambda for cost optimization. Conversely, users like FlyingHawk and Liongeek argue that managed State Manager documents are easier than writing Lambda code, but this overlooks the fact that State Manager does not natively handle the "schedule" aspect as elegantly as EventBridge without additional orchestration layers.

Official Reference

These links open the official vendor documentation in a new tab.

Exam Strategy

When asked for 'least operational overhead' involving schedules, prefer EventBridge over CloudWatch Alarms or manual scripts. Do not confuse configuration management tools (State Manager) with automation/orchestration tools (EventBridge/Lambda) for simple lifecycle tasks.

Frequently Asked Questions

Why isn't Systems Manager State Manager the best choice for scheduling?

State Manager is designed for maintaining desired configurations (compliance), not for simple scheduled start/stop events. Using it requires more setup than EventBridge's native scheduling.

Can I use CloudWatch Alarms to stop RDS at night?

No, CloudWatch Alarms trigger on metric thresholds (like CPU usage), not time-based schedules. EventBridge is the correct service for time-based triggers.

More SAA-C03 FAQ →

Community Votes

D
56%
C
44%

56% of anonymous learners picked answer D. Votes are pick records left by other test-takers — they are not the verified answer.

Discussion 13 contributions

Compiled from public community threads and reader submissions, lightly edited for clarity. Handles and vote tallies are shown as recorded, and comments reflect the views of individual contributors.

From public community threads 13

  1. AbhiBK 👍 4
    To meet the requirement of running Amazon RDS DB instances only during business hours with the least operational overhead, the best solution would be: D. Create an Amazon EventBridge rule that invokes AWS Lambda functions to start and stop the RDS instances. This approach allows you to automate the scheduling of start and stop actions using EventBridge rules, which can trigger Lambda functions based on a cron expression. This setup is straightforward and requires minimal ongoing management
  2. KaZimirovich 👍 4 Answered D
    While AWS Systems Manager State Manager can be used to manage configuration states of AWS resources, it is generally more complex to set up for straightforward use cases like schedule-based starting and stopping of RDS instances compared to using a direct scheduling method through EventBridge.
  3. nebajp 👍 4 Answered C
    Correct Answer us C - it allows you to define and automatically enforce desired configurations for EC2 and RDS.
  4. FlyingHawk 👍 3 Answered C
    based on the AWS doc, you can use AWS Systems Manager State Manager associations to start and stop the RDS instances: 1. https://docs.aws.amazon.com/systems-manager-automation-runbooks/latest/userguide/automation-ref-rds.html AWS-StartRdsInstance AWS-StartStopAuroraCluster AWS-StopRdsInstance 2. https://docs.aws.amazon.com/systems-manager/latest/userguide/scheduling-automations-state-manager-associations.html D is also workable solution, but it will take more effort to implement.
  5. bujuman 👍 3 Answered D
    AWS Systems Manager State Manage has limitations regarding MSQL and the Db engine is not mentioned. Check the this link to confirm D option : https://aws.amazon.com/blogs/database/save-costs-by-automating-the-start-and-stop-of-amazon-rds-instances-with-aws-lambda-and-amazon-eventbridge/
Show 8 more comments
  1. ieffiong 👍 2 Answered D
    When comparing the two: Option C is less straightforward because State Manager isn’t designed specifically for start/stop operations on RDS. It would likely require additional complexity (e.g., custom automation documents and potential workarounds) to achieve a scheduled start/stop functionality. Option D leverages EventBridge’s native scheduling capabilities to invoke Lambda functions, offering a more direct and streamlined approach with the least operational overhead.
  2. dhewa 👍 2 Answered C
    AWS Systems Manager State Manager allows you to automate the process of starting and stopping RDS instances based on a defined schedule.
  3. LeonSauveterre 👍 1 Answered C
    A - CloudWatch alarms are designed to respond to metric thresholds (like CPU/memory utilization) rather than schedules. B - Trusted Advisor provides cost optimization and resource usage recommendations but can't schedule anything. D - Works but more complicated than option C. We don't wanna manually compose and then maintain lambda functions right?
  4. hharbiordun85 👍 1
    D. Amazon EventBridge allows you to create rules based on a schedule (using cron expressions) to automate tasks. You can set up rules to start the RDS instances at the beginning of business hours and stop them at the end of business hours. By using AWS Lambda in conjunction with EventBridge, you can create functions that handle
  5. Liongeek 👍 1 Answered C
    Setting State Manager with AWS managed Documents (StartEC2Instance, StopEC2Instance, StartRDSInstance and StopRDSInstance) it's easier and faster than creating your own Lambda functions and event bridge rules. Letter C is the answ.
  6. jingen11 👍 1 Answered C
    Start, restart, or stop managed nodes and Amazon Relational Database Service (Amazon RDS) instances.
  7. komorebi 👍 4 Answered D
    Answer is D
  8. siheom 👍 2 Answered D
    VOTE D

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