DVA-C02 Exam Guide
This DVA-C02 exam focuses on practical knowledge and real-world application scenarios related to the subject area. It evaluates your ability to understand core concepts, apply best practices, and make informed decisions in realistic situations rather than relying solely on memorization.
This page provides a structured exam guide, including exam focus areas, skills measured, preparation recommendations, and practice questions with explanations to support effective learning.
Exam Overview
The DVA-C02 exam typically emphasizes how concepts are used in professional environments, testing both theoretical understanding and practical problem-solving skills.
Skills Measured
- Understanding of core concepts and terminology
- Ability to apply knowledge to practical scenarios
- Analysis and evaluation of solution options
- Identification of best practices and common use cases
Preparation Tips
Successful candidates combine conceptual understanding with hands-on practice. Reviewing measured skills and working through scenario-based questions is strongly recommended.
Practice Questions for DVA-C02 Exam
The following practice questions are designed to reinforce key DVA-C02 exam concepts and reflect common scenario-based decision points tested in the certification.
Question#1
A developer needs to migrate an online retail application to AWS to handle an anticipated increase in traffic. The application currently runs on two servers: one server for the web application and another server for the database. The web server renders webpages and manages session state in memory.
The database server hosts a MySQL database that contains order details. When traffic to the application is heavy, the memory usage for the web server approaches 100% and the application slows down considerably.
The developer has found that most of the memory increase and performance decrease is related to the load of managing additional user sessions. For the web server migration, the developer will use Amazon EC2 instances with an Auto Scaling group behind an Application Load Balancer.
Which additional set of changes should the developer make to the application to improve the application's performance?
A. Use an EC2 instance to host the MySQL database. Store the session data and the application data in the MySQL database.
B. Use Amazon ElastiCache for Memcached to store and manage the session data. Use an Amazon RDS for MySQL DB instance to store the application data.
C. Use Amazon ElastiCache for Memcached to store and manage the session data and the application data.
D. Use the EC2 instance store to manage the session data. Use an Amazon RDS for MySQL DB instance to store the application data.
Explanation:
Using Amazon ElastiCache for Memcached to store and manage the session data will reduce the memory load and improve the performance of the web server. Using Amazon RDS for MySQL DB instance to store the application data will provide a scalable, reliable, and managed database service.
Option A is not optimal because it does not address the memory issue of the web server.
Option C is not optimal because it does not provide a persistent storage for the application data.
Option D is not optimal because it does not provide a high availability and durability for the session data.
Reference: Amazon ElastiCache, Amazon RDS
Question#2
A developer is building a multi-tenant application using AWS Lambda, Amazon S3, and Amazon DynamoDB. Each S3 object prefix represents a tenant name, and DynamoDB uses the tenant name as the partition key.
The developer must prevent cross-tenant data access during processing.
Which combination of actions will meet this requirement? (Select THREE.)
A. Create a data access IAM role that allows the sts: TagSession action.
B. Allow the Lambda execution role to assume the data access role.
C. Configure IAM policies on the data access role to allow S3 and DynamoDB access only when
resource attributes match the tenant session tag.
D. Create a resource-based policy on DynamoDB based on principal tags.
E. Create a resource control policy (RCP) for the S3 bucket.
F. Configure the Lambda function to assume the data access role and pass the tenant name as a session tag.
Explanation:
Comprehensive and Detailed Explanation (250C300 words):
AWS best practices for multi-tenant isolation recommend session-based access control using IAM session tags. Session tags allow temporary credentials to be scoped dynamically based on tenant context.
First, the data access role must allow sts: TagSession (Option A) so tenant identifiers can be passed securely at runtime. The Lambda function assumes this role and includes the tenant name as a session tag (Option F).
Next, IAM policies on the data access role restrict access to S3 object prefixes and DynamoDB partition keys by evaluating the session tag (Option C). This ensures that even if a bug occurs, the role cannot access data belonging to another tenant.
Resource-based DynamoDB policies and RCPs are unnecessary here and add complexity.
This approach follows AWS’s recommended attribute-based access control (ABAC) model and provides strong tenant isolation with minimal operational overhead.
Question#3
An ecommerce application is running behind an Application Load Balancer. A developer observes some unexpected load on the application during non-peak hours. The developer wants to analyze patterns for the client IP addresses that use the application.
Which HTTP header should the developer use for this analysis?
A. The X-Forwarded-Proto header
B. The X-F Forwarded-Host header
C. The X-Forwarded-For header
D. The X-Forwarded-Port header
Explanation:
The HTTP header that the developer should use for this analysis is the X-Forwarded-For header. This header contains the IP address of the client that made the request to the Application Load Balancer. The developer can use this header to analyze patterns for the client IP addresses that use the application. The other headers either contain information about the protocol, host, or port of the request, which are not relevant for the analysis.
Reference: How Application Load Balancer works with your applications
Question#4
A company runs a web application on Amazon EC2 instances behind an Application Load Balancer.
The application uses Amazon DynamoDB as its database. The company wants to ensure high performance for reads and writes.
Which solution will meet these requirements MOST cost-effectively?
A. Configure auto-scaling for the DynamoDB table with a target utilization of 70%. Set the minimum and maximum capacity units based on the expected workload.
B. Use DynamoDB on-demand capacity mode for the table. Specify a maximum throughput higher than the expected peak read and write capacity units.
C. Use DynamoDB provisioned throughput mode for the table. Create an Amazon CloudWatch alarm on the ThrottledRequests metric. Invoke an AWS Lambda function to increase provisioned capacity.
D. Create an Amazon DynamoDB Accelerator (DAX) cluster. Configure the application to use the DAX endpoint.
Explanation:
Why Option A is Correct: Auto-scaling with a target utilization ensures the DynamoDB table dynamically adjusts capacity based on workload, maintaining high performance while optimizing cost. Setting a reasonable target utilization minimizes overprovisioning and throttling risks.
Why Other Options are Incorrect:
Option B: On-demand capacity is costlier than provisioned throughput for predictable workloads.
Option C: Using manual CloudWatch alarms and Lambda for scaling is less efficient and adds operational overhead.
Option D: DAX accelerates read performance but does not improve write performance.
AWS Documentation
Reference: DynamoDB Auto Scaling
Disclaimer
This page is for educational and exam preparation reference only. It is not affiliated with Amazon, Certified Developer - Associate, or the official exam provider. Candidates should refer to official documentation and training for authoritative information.
