Cost-Optimizing Dev Environments with Auto Scaling Limits

SAA-C03 By islever Editorial Last updated

Design cost-optimized compute solutions.

Short answer

D Reduce the maximum number of EC2 instances in the development environment’s Auto Scaling group.

Question

A company is launching an application on AWS. The application uses an Application Load Balancer (ALB) to direct traffic to at least two Amazon EC2 instances in a single target group. The instances are in an Auto Scaling group for each environment. The company requires a development environment and a production environment. The production environment will have periods of high traffic.
Which solution will configure the development environment MOST cost-effectively?
  1. Reconfigure the target group in the development environment to have only one EC2 instance as a target.
  2. Change the ALB balancing algorithm to least outstanding requests.
  3. Reduce the size of the EC2 instances in both environments.
  4. Reduce the maximum number of EC2 instances in the development environment’s Auto Scaling group. Correct Answer

Key Takeaways

The trap is choosing to reduce the minimum/targets (Option A) which violates HA requirements; the correct approach is capping the maximum scale (Option D) to prevent waste during idle periods.

Learn why reducing the maximum capacity in an Auto Scaling group is the most cost-effective way to optimize a low-traffic development environment on AWS without violating ALB redundancy requirements.

Common mistake: Choosing Option A because it seems to save the most money by running fewer instances. However, this fails because ALBs require at least two targets for reliability, and the question explicitly states the ALB directs traffic to at least two instances. Option A breaks the architecture.

Expert Analysis

The question asks for the MOST cost-effective solution to configure the development environment, given that the ALB requires at least two EC2 instances in the target group.

Option A suggests reconfiguring the target group to have only one EC2 instance. This directly violates the constraint stated in the prompt ('direct traffic to at least two Amazon EC2 instances'). Furthermore, AWS ALBs generally require a minimum of two healthy targets in different Availability Zones for high availability and fault tolerance. Reducing this to one instance compromises resilience and violates the architectural requirement, making it an invalid and incorrect choice despite the potential cost savings.

Option D suggests reducing the maximum number of EC2 instances in the development environment’s Auto Scaling group. The development environment typically does not experience high traffic like production. By lowering the upper limit (maximum capacity) of the ASG, you ensure that even if scaling policies trigger, no more than a small number of instances are launched. This prevents over-provisioning during minor spikes while still allowing the system to maintain the required minimum of two instances for HA. This is a precise, policy-based cost optimization technique specific to AWS.

Options B and C do not address the core issue of right-sizing the development environment's capacity limits. Changing the algorithm (B) affects distribution, not count/cost directly in a way that reduces baseline or max costs significantly compared to capacity limits. Reducing instance size (C) might save money but could impact performance unnecessarily and doesn't address the 'development vs production' workload difference as effectively as managing scale limits.

Official Reference

https://docs.aws.amazon.com/autoscaling/ec2/userguide/auto-scaling-groups.html

This link opens the official vendor documentation in a new tab.

Exam Strategy

Always check for constraints in the question stem first. If the question states 'at least two instances,' any option that reduces the count below two (like Option A) is automatically incorrect, regardless of its cost-saving appeal. Focus on options that manage capacity limits (min/max/desired) rather than breaking architectural rules.

Frequently Asked Questions

Can I use only one EC2 instance with an ALB?

While technically possible in single-AZ setups, AWS best practices and many exam scenarios assume multi-AZ deployments where ALBs require at least two healthy targets for high availability. The question explicitly mandates 'at least two' instances.

Does reducing the ASG maximum always save money?

It saves money by preventing the launch of unnecessary instances during traffic spikes that the dev environment doesn't need. It ensures you pay only for what is needed up to a capped limit.

More SAA-C03 FAQ →

Community Votes

A
57%
D
40%
C
3%

57% of anonymous learners picked answer A. Votes are pick records left by other test-takers — they are not the verified answer.

Discussion 60 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 30 of 60

  1. mhmt4438 👍 20 Answered D
    D. Reduce the maximum number of EC2 instances in the development environment’s Auto Scaling group This option will configure the development environment in the most cost-effective way as it reduces the number of instances running in the development environment and therefore reduces the cost of running the application. The development environment typically requires less resources than the production environment, and it is unlikely that the development environment will have periods of high traffic that would require a large number of instances. By reducing the maximum number of instances in the development environment's Auto Scaling group, the company can save on costs while still maintaining a functional development environment.
  2. pentium75 👍 10 Answered D
    A modifies only the ALB target group (= directs traffic only to one node), but does not affect the number of nodes (and the cost) B balances load between nodes but does not affect the cost C impacts the prod environment so that would be unable to handle its "periods of high traffic" D makes sure that the dev environment will not scale to more than 2 instances, as does the prod environment
  3. JayBee65 👍 10
    No, it will not reduce the number of instances being used, since a minimum of 2 will be used at all times.
  4. awsgeek75 👍 6 Answered D
    B and C don't actually save any cost without impacting performance during high traffic on production. A and D are basically same thing but A enforces a limit of one EC2 instance which is not acceptable as the question asks: "Application Load Balancer (ALB) to direct traffic to at least two Amazon EC2 instances in a single target group. The instances are in an Auto Scaling group for each environment" Hence D is the only valid answer.
  5. cookieMr 👍 5 Answered A
    By configuring the target group in the development environment to have only one EC2 instance as a target, you are effectively reducing the resources allocated to that environment. This helps minimize costs by utilizing fewer EC2 instances and associated resources. Option B does not directly address the cost-effectiveness of the development environment. It focuses on load balancing strategies rather than cost optimization. Option C may not be the most cost-effective solution unless the current instance sizes are over-provisioned or unnecessary for the application's requirements. Option D can help reduce costs, but it may impact the environment's ability to handle traffic and scale efficiently, especially during periods of increased load. Overall, option A provides a cost-effective approach by minimizing the resources allocated to the development environment while still maintaining a functional setup.
Show 25 more comments
  1. Priyapani 👍 5 Answered D
    In the question it is said minimum it should have 2 instances in Target group. So in development group we can reduce the the target group. In option A. It is said it will have only one instance in development group that doesn't match to our question
  2. pentium75 👍 5
    But it will keep the number of instances at two, while the production environment has "AT LEAST two".
  3. MiniYang 👍 4 Answered D
    the correct answer is D. This is from Amazon Q : The most cost-effective way to configure the development environment would be to reduce the maximum number of EC2 instances in the development environment's Auto Scaling group (Option D). The most cost-effective way to configure the development environment would be to reduce the maximum number of EC2 instances in the development environment's Auto Scaling group (Option D).The most cost-effective way to configure the development environment would be to reduce the maximum number of EC2 instances in the development environment's Auto Scaling group (Option D).
  4. ChrisAn 👍 4 Answered A
    A# By reducing the number of EC2 instances in the target group of the development environment to just one, you can lower the cost associated with running multiple instances. Since the development environment typically has lower traffic and does not require the same level of availability and scalability as the production environment, having a single instance is sufficient for testing and development purposes.
  5. kerl 👍 4
    my opinion, A is wrong, if you remove the instance in the Target Group, ASG will reprovision to match the minimum/desire number of instance. I choose D because i can configure my ASG to assigned minimum / maximum to 1. ASG will automatically create the instanced and add into the Target Group. If u delete the instance, ASG will reprovison and readd into the Target Group. So A is wrong. Answer is D
  6. TheFivePips 👍 4 Answered D
    The application uses an Application Load Balancer (ALB) to direct traffic to at least two Amazon EC2 instances in a single target group You are required to keep at least two instances in each target group. A sets it to one, which would be more cost effective, but doesnt meet the requirement.
  7. ErfanKh 👍 4 Answered A
    I am voting A here, there is no need for Autoscaling since we can just set dev environment to 1 EC2 instance which would be the lowest cost.
  8. Aninina 👍 3 Answered D
    D. Reduce the maximum number of EC2 instances in the development environment’s Auto Scaling group This will help to configure the development environment more cost-effectively as it reduces the maximum number of instances that can be launched at a time, which in turn reduces the costs associated with running the instances. Since the development environment is not expected to experience periods of high traffic, it will not require as many instances as the production environment, thus reducing costs. It's worth noting that if the traffic is not high and the instances are not being utilized, the cost of running instances is the same as having them idle. So, the best cost-effective solution will be to have the minimum number of instances that can handle the traffic and scale it up as needed.
  9. ravinperera 👍 3 Answered D
    This option is specific to the development environment and focuses on reducing the number of instances that can be spun up during scaling events. This means cost savings because fewer instances will be used even if the scaling policies are triggered. Given the goal to configure the development environment in the most cost-effective way, without compromising the production environment, the best option is D
  10. MatAlves 👍 3 Answered D
    So, in short, the question asks for a way to reduce cost wasted with the dev env, since it's resources are being underused. (A)Target group vs (B) Auto Scaling Group. Reducing the target group won't affect the number of "nodes" (instances), cost will stay the same. To eliminate the excess of ec2 instances in the dev env, you actually need to reduce the auto scaling group.
  11. Michal_L_95 👍 3
    But the question states: "The application uses an Application Load Balancer (ALB) to direct traffic to at least two Amazon EC2 instances in a single target group." Which means that we can not reduce number of instances to 1 as each stage is different target group. D is the right option.
  12. LuckyAro 👍 3 Answered A
    A: Reconfigure the target group in the development environment to have only one EC2 instance as a target. D will defeat the purpose of having the EC2 in an auto scaling group because limiting it to only one instance means it can't auto-scale over that single instance.
  13. awsgeek75 👍 3
    Wrong, think more. A reduces to one instance whereas: "The application uses an Application Load Balancer (ALB) to direct traffic to at least two Amazon EC2 instances in a single target group" The ALB NEEDS at least 2 instances so where is your second instance?
  14. aws4myself 👍 3 Answered D
    A is wrong - if it is an auto-scaling group, then if you remove it from the target group also it will not be deleted/ terminated. So there is no cost reduction. But for D, if you reduce the max capacity, EC2 will be terminated.
  15. Chef_couincouin 👍 3
    Answear is A but I'am not agree. We use only one instance with A and D. But with D, by default, instance is terminated whereas with A, instance still exist. Answear should be D
  16. G3 👍 3
    B. https://aws.amazon.com/about-aws/whats-new/2019/11/application-load-balancer-now-supports-least-outstanding-requests-algorithm-for-load-balancing-requests/
  17. K0nAn 👍 3 Answered A
    Since option D says that decrease max number ,it will not affect minimum number which 2 ,it will be always same ,so option A makes sense for me
  18. Steve_4542636 👍 3 Answered A
    Dev doesn't need autoscaling so setting it to one is the most COST effective solution, not the most operationally efficient
  19. HaineHess 👍 3 Answered A
    it's A (D does not reduce €)
  20. LeonSauveterre 👍 2
    Weird... ChatGPT says to choose D when I asked about this question. It said option A compromises high availability because ALBs require at least two targets for redundancy and fault tolerance, so not a valid option due to the risk of downtime if the single instance becomes unavailable, while option D provides targeted cost optimization for the development environment without compromising availability or production performance.
  21. forzadejan 👍 2
    D. Reduce the maximum number of EC2 instances in the development environment’s Auto Scaling group. This option will reduce the number of instances running in the development environment, which will decrease the cost of running the environment. The other options do not directly address the cost of running the development environment.
  22. Its_SaKar 👍 2 Answered A
    Option A because it can't be option D as there should be at least two EC2 instances in Auto scaling group, and can't be reduced to one as said in option D. So, simply reconfigure the target group in the development environment to have only one EC2 instance as a target as said in option A to reduce cost.
  23. XXXXXlNN 👍 2
    chatGPT sucks too. it says A, but A abviously just says reduced the number of Target Group, reduce Target Group does not mean the reduce of EC2 instances themself, so there is no cost saved at all. Thus DDDDDDDDDD....
  24. pentium75 👍 2
    No, you're confusing "target group" (of the ALB) with "Auto Scaling group". Answer A will direct ALB traffic only to one node, but it does not affect the number of nodes in any way (it will still be "at least two").
  25. AlmeroSenior 👍 2 Answered D
    You cant use a Target Group to change ASG behavior guys . ALB's Target Group is pointing to an ASG . So no amount to TG tweaking is going to lead to a scale in opportunity on ASG side .

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