Question 1mediummultiple choice
Full question →mediummultiple choiceObjective-mapped
A company runs a web application on a fleet of Amazon EC2 instances behind an Application Load Balancer. The application has predictable traffic patterns with high traffic during business hours and low traffic at night. The SysOps administrator wants to reduce compute costs while ensuring the application remains responsive during peak hours. The administrator has already implemented Auto Scaling based on CPU utilization. Which additional action should the administrator take to optimize costs?
Answer choices
Why each option matters
Good practice is not just finding the correct option. The wrong answers often show the exact trap the exam wants you to fall into.
A
Distractor review
Use On-Demand instances only
On-Demand pricing offers no discount and is the most expensive option for a predictable workload. It does not take advantage of any cost-saving purchasing options.
B
Best answer
Purchase Reserved Instances for the baseline capacity and use Spot Instances for the additional capacity during peak hours
This approach minimizes costs by applying the highest discount (Reserved Instances) to the steady-state capacity and leveraging the cost savings of Spot Instances for the flexible, peak-demand capacity. Auto Scaling can be configured to launch Spot Instances as needed, providing both cost efficiency and performance.
C
Distractor review
Increase the minimum number of instances in the Auto Scaling group
Increasing the minimum number of instances would keep more instances running during low-traffic periods, increasing costs unnecessarily without improving peak responsiveness.
D
Distractor review
Use Dedicated Hosts to reduce licensing costs
Dedicated Hosts are primarily used for compliance or to reduce software licensing costs when using certain server-bound licenses. They are typically more expensive than shared tenancy and do not directly address compute cost optimization for a standard web application.
Common exam trap
Common exam trap: NAT rules depend on direction and matching traffic
NAT is not only about the public address. The inside/outside interface roles and the ACL or rule that matches traffic are just as important.
Technical deep dive
How to think about this question
NAT questions usually test address translation, overload/PAT behaviour, static mappings and whether the right traffic is being translated. Read the interface direction and address terms carefully.
KKey Concepts to Remember
- Static NAT maps one inside address to one outside address.
- PAT allows many inside hosts to share one public address using ports.
- Inside local and inside global describe the private and translated addresses.
- NAT ACLs identify traffic for translation, not always security filtering.
TExam Day Tips
- Identify inside and outside interfaces first.
- Check whether the scenario needs static NAT, dynamic NAT or PAT.
- Do not confuse NAT matching ACLs with normal packet-filtering intent.
Related practice questions
Related SOA-C02 practice-question pages
Use these pages to review the topic behind this question. This is how one missed question becomes focused revision.
More questions from this exam
Keep practising from the same exam bank, or move into a focused topic page if this question exposed a weak area.
Question 1
A company uses Amazon CloudFront to deliver content to a global audience. The origin is an Application Load Balancer in us-east-1. The SysOps administrator wants to reduce costs by minimizing the number of requests that reach the origin server. Which action should the administrator take?
Question 2
A company runs a batch processing application on Amazon EC2 that runs for 2 hours every night. The workload can tolerate interruptions. Which EC2 purchasing option provides the lowest cost for this use case?
Question 3
A SysOps administrator needs to monitor the CPU utilization of an Amazon RDS DB instance and receive an alarm when CPU utilization exceeds 80% for 5 consecutive minutes. Which AWS service should be used to create this alarm?
Question 4
A company runs a critical web application on Amazon EC2 instances in an Auto Scaling group behind an Application Load Balancer (ALB). The application uses session stickiness (sticky sessions) to maintain user sessions. The SysOps administrator notices that when instances are replaced during a scale-in or failure event, users lose their session data. The administrator needs to preserve session data across instance failures without losing stickiness benefits. What should the administrator do?
Question 5
A company runs a production web application on a single Amazon EC2 instance. The application experiences a predictable and steady workload 24/7. The SysOps administrator wants to minimize compute costs for this instance while ensuring it remains available during the expected workload. Which EC2 purchasing option should the administrator use?
Question 6
A company has a VPC with public and private subnets. The private subnets host application servers that need to make outbound HTTPS connections to the internet. The SysOps administrator must implement a solution that provides outbound internet connectivity while preventing inbound connections from the internet. Additionally, the solution must allow the company to control which domains the application servers can access. Which solution should the administrator implement?
FAQ
Questions learners often ask
What does this SOA-C02 question test?
Static NAT maps one inside address to one outside address.
What is the correct answer to this question?
The correct answer is: Purchase Reserved Instances for the baseline capacity and use Spot Instances for the additional capacity during peak hours — The most effective cost optimization strategy for a predictable, variable workload is to combine Reserved Instances (RIs) for the baseline capacity with Spot Instances for the flexible capacity that handles traffic spikes. Reserved Instances provide a significant discount compared to On-Demand pricing for a commitment to a steady-state capacity. Spot Instances offer even larger discounts for interruptible workloads, which is acceptable because during peak hours the additional capacity can be coordinated with Auto Scaling to use Spot Instances, and if Spot instances are reclaimed, the Auto Scaling group can fall back to On-Demand or rebalance. Option B achieves this by using RIs for the minimum required capacity and Spot for the dynamic peak portion. Option A (using only On-Demand) does not optimize costs. Option C (increasing the minimum number of instances) would raise costs during low-traffic periods. Option D (using Dedicated Hosts) is generally more expensive and only beneficial for specific licensing requirements, not general cost optimization.
What should I do if I get this SOA-C02 question wrong?
Then try more questions from the same exam bank and focus on understanding why the wrong options are tempting.
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