Question 1mediummultiple choice
Full question →mediummultiple choiceObjective-mapped
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?
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
Best answer
Disable sticky sessions on the ALB and configure the application to store session data in an external session store like Amazon ElastiCache for Redis.
This decouples session state from the EC2 instance. If an instance fails, any other instance can retrieve the session from ElastiCache, preserving the session for the user.
B
Distractor review
Increase the stickiness duration to a very high value so that sessions are not lost during brief interruptions.
Stickiness only controls how long the load balancer binds a user to an instance. If the instance fails, the session is lost regardless of the duration.
C
Distractor review
Change the Auto Scaling group to use a larger instance type to handle more sessions per instance, reducing the likelihood of session loss.
This does not prevent data loss if an instance fails. Sessions are still stored locally on the instance.
D
Distractor review
Configure the Auto Scaling group to use a larger minimum size and a lower maximum, so instances are less likely to be terminated.
While this reduces the frequency of scale-in events, it does not protect against instance failures. Sessions are still lost on instance termination.
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 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 5
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?
Question 6
A company has a VPC with a public subnet and a private subnet. An Amazon EC2 instance in the private subnet needs to download security patches from the internet, but the instance must not be directly accessible from the internet. The SysOps administrator configured a NAT gateway in the public subnet and added a route in the private subnet's route table pointing 0.0.0.0/0 to the NAT gateway. The instance's security group allows all outbound traffic. However, the instance still cannot reach the internet. What is the most likely missing configuration?
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: Disable sticky sessions on the ALB and configure the application to store session data in an external session store like Amazon ElastiCache for Redis. — Sticky sessions cause the ALB to bind a user's session to a specific instance. If that instance fails, the session is lost. To preserve sessions across instance failures, session data must be stored externally in a centralized data store such as Amazon ElastiCache or DynamoDB. The ALB stickiness should be disabled and replaced with application-managed sessions. Alternatively, using a shared session store with a cookie-based approach can work. Simply increasing the instance size or using a larger Auto Scaling group does not solve the data loss. Changing the stickiness duration does not help.
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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