AWS Certified Developer Associate 2018 AWS Certified Developer Associate 2018 Free Practice Test — 30 Questions

Question 1

A development team is architecting a serverless data processing pipeline using AWS Lambda and Amazon Simple Queue Service (SQS). They have configured an SQS queue to send messages in batches of up to 10 messages per poll. The Lambda function, designed to process these messages, has been configured with a `ReservedConcurrency` setting of 50 to ensure predictable performance and prevent other services from being impacted. Considering the SQS event source mapping and the Lambda function\'s concurrency configuration, what is the maximum number of concurrent Lambda function invocations that can be initiated by the SQS polling mechanism at any given moment?

Accepted Answer

50

Question 2

A rapidly growing e-commerce platform is experiencing an unprecedented surge in user activity. Their primary product catalog API is powered by an AWS Lambda function. During a peak hour, the function\'s invocation rate jumps from a baseline of 50 requests per second to an average of 150 requests per second, with each invocation taking approximately 2 seconds to complete. The AWS account has a default concurrency limit of 1000. Assuming no other Lambda functions are consuming significant concurrency, which of the following is the most probable cause for potential service degradation or outright failure of the product catalog API during this surge?

Accepted Answer

The Lambda function's configured provisioned concurrency limit, if set lower than the peak concurrent executions, is exceeded.

Question 3

A rapidly growing e-commerce platform relies on AWS Lambda functions for processing user orders. During a flash sale event, the platform experiences a tenfold increase in concurrent user sessions, leading to a significant surge in order requests. Developers observe intermittent `TooManyRequestsException` errors being returned to users, indicating that the Lambda functions are being throttled due to exceeding concurrency limits. The development team needs to implement a solution that absorbs these sudden traffic spikes, prevents Lambda throttling, and ensures a consistent user experience without requiring manual intervention to adjust concurrency settings during the event.

Accepted Answer

Integrate an Amazon SQS queue between the API Gateway and the Lambda function to buffer incoming order requests, allowing Lambda to process them at a controlled rate.

Question 4

A company is developing a new IoT platform that collects real-time sensor readings from thousands of devices. The platform needs to ingest this data reliably, process it for anomalies, and store the processed results for historical analysis. The system must be designed to remain operational and prevent data loss even if an entire AWS Availability Zone within a region becomes unavailable. Which combination of AWS services would best satisfy these requirements for high availability and durability in data ingestion, processing, and storage?

Accepted Answer

Amazon Kinesis Data Streams for ingestion, AWS Lambda for processing, and Amazon DynamoDB for storage.

Question 5

A development team building a customer-facing web application hosted on AWS has identified intermittent latency issues when users upload and retrieve image files. The application leverages Amazon S3 to store these files and employs a custom AWS Identity and Access Management (IAM) policy to govern access. The current IAM policy grants read and write permissions to a broad S3 bucket prefix, incorporating several conditions related to user attributes and IP address ranges. After exhausting other potential causes such as network configuration and application code optimization, the team suspects the IAM policy\'s complexity might be contributing to the observed performance degradation. Which of the following adjustments to the IAM policy would most likely mitigate the intermittent latency by optimizing access control evaluation?

Accepted Answer

Refine the IAM policy to grant access only to specific S3 object prefixes and actions, removing broad wildcards and complex conditions where possible.

Question 6

A development team is building a customer-facing web application using AWS Lambda for backend processing. The Lambda function responsible for handling user profile updates is configured with default concurrency settings. During a promotional event, the application experiences a sudden and massive influx of user requests. This surge overwhelms the function\'s capacity, and users begin reporting that their profile updates are not being processed, and the application appears frozen for new requests. What is the most probable underlying AWS behavior causing this observed unresponsiveness?

Accepted Answer

New invocations are being throttled due to exceeding the account's unreserved concurrency limits for Lambda.

Question 7

A company\'s customer-facing web portal, deployed on AWS Elastic Beanstalk, is experiencing significant user complaints regarding lost shopping cart data and interrupted workflows. The application uses Amazon RDS for its primary data persistence. Analysis of deployment logs reveals that the application instances are frequently scaled up and down based on traffic patterns. Developers suspect that session data is not being consistently maintained across these instances, leading to data corruption or loss when a user\'s request is routed to a different instance. What AWS service, when integrated with the application\'s backend, would most effectively address this session state management challenge while maintaining application responsiveness?

Accepted Answer

AWS ElastiCache for Redis

Question 8

A development team is building a customer profile management system composed of several independent microservices deployed on AWS. When a user updates their profile information, this event should trigger two subsequent actions: first, an update to a recommendation engine, and second, an invalidation of a user\'s cached data. Crucially, the cache invalidation should only occur if the recommendation engine update successfully completes. If the recommendation engine update fails after exhausting its retry attempts, the system should log the failure and notify an operations team, but it must not proceed to invalidate the cache. Which AWS service best facilitates this complex, stateful orchestration of asynchronous microservice calls, ensuring sequential execution and robust error handling?

Accepted Answer

AWS Step Functions

Question 9

A software development team, tasked with building a new customer-facing application for a retail conglomerate, is experiencing significant disruption. Stakeholders, who are spread across various business units, frequently introduce new feature requests and modify existing ones with little advance notice, often mid-development cycle. This has led to missed deadlines, team frustration, and a decline in overall productivity as developers struggle to re-prioritize and adapt their work constantly. Which of the following approaches would best equip the team to manage this dynamic environment and maintain effective delivery?

Accepted Answer

Implement a Scrum framework, focusing on short, iterative sprints, regular stakeholder feedback sessions during sprint reviews, and team retrospectives to adapt processes.

Question 10

A startup\'s flagship mobile application, designed for real-time collaborative document editing, experiences a sudden, unexpected surge in demand for offline functionality due to widespread internet instability in key user regions. The development team, accustomed to a robust, always-connected architecture, must rapidly shift its focus to implement a reliable offline-first synchronization strategy. This requires not only a significant re-architecture of the data persistence and conflict resolution mechanisms but also a complete re-evaluation of the user experience design. The product manager is concerned about maintaining user trust and preventing data loss during this transition, while the engineering lead is focused on the technical feasibility and speed of implementation. Which of the following core behavioral competencies is MOST critical for the development team to successfully navigate this abrupt change in project direction and technical requirements?

Accepted Answer

Adaptability and Flexibility, coupled with strong Problem-Solving Abilities and Initiative and Self-Motivation.

Question 11

A team is developing a microservices-based application deployed on Amazon Elastic Kubernetes Service (EKS). The application experiences significant performance degradation during peak hours, characterized by increased API response times and intermittent failures when retrieving configuration data from a central AWS Systems Manager Parameter Store. Analysis of application logs reveals that the primary bottleneck is the high volume of concurrent read requests to Parameter Store for small, frequently accessed configuration values, leading to throttling. The team needs to implement a solution that minimizes direct calls to Parameter Store for these specific data points while ensuring that updates to these configurations are still propagated efficiently.

Accepted Answer

Integrate Amazon ElastiCache for Redis as an in-memory cache within the microservices, pre-populating it with frequently accessed configuration parameters from Parameter Store and implementing a cache-aside pattern for reads.

Question 12

A team is developing a critical backend service deployed as an AWS Lambda function. During peak traffic hours, the service exhibits intermittent failures, characterized by HTTP 5xx errors and timeouts, despite the Lambda function itself not reaching its configured concurrency limits. Analysis suggests that the downstream dependencies, while generally performant, become unresponsive when subjected to the sudden, high volume of requests generated by the scaled-out Lambda function. Which architectural pattern would most effectively mitigate this issue by introducing a buffer and controlling the rate of requests to downstream services?

Accepted Answer

Implement an Amazon SQS queue between the API Gateway and the Lambda function to buffer incoming requests and allow the Lambda function to process them at a controlled rate.

Question 13

A team is developing a microservices-based application deployed on AWS Lambda, processing real-time inventory updates from various sources. Multiple Lambda function instances may concurrently attempt to modify the same inventory item record in an Amazon DynamoDB table, which stores quantity and last updated timestamp. To prevent data corruption and ensure that each update reflects the latest state, which of the following approaches is the most appropriate for maintaining data consistency at the item level?

Accepted Answer

Implement optimistic locking using DynamoDB conditional expressions, checking a version attribute before updating, and using a Lambda function to handle retries on failed attempts.

Question 14

A dynamic e-commerce platform, deployed on AWS, is experiencing significant user complaints regarding slow product page loading times during flash sales. Initial troubleshooting indicated that while EC2 instance utilization was high, scaling up compute resources did not fully alleviate the issue. Further analysis of application logs revealed that a critical API endpoint, responsible for fetching real-time inventory levels from a third-party service, was frequently timing out, causing cascading delays across the application. The development team, demonstrating adaptability, is now tasked with devising a strategy to improve performance and resilience without immediate architectural overhaul, focusing on enhancing the handling of this external dependency. Which of the following approaches best addresses the root cause of the performance degradation while aligning with the principles of building robust cloud-native applications?

Accepted Answer

Implement Amazon ElastiCache for Redis to cache frequently accessed product inventory data, reducing direct calls to the external service and providing faster responses to users.

Question 15

During a high-stakes product launch, the primary customer-facing web application experiences a sudden, significant increase in user traffic, far exceeding anticipated load. This surge triggers performance degradation, including increased latency and intermittent unresponsiveness. The development team\'s immediate priority shifts from feature deployment to service stability. Considering the need to adapt to changing priorities and maintain operational effectiveness during this critical transition, what is the most prudent initial action for the lead developer to take to address the situation and ensure minimal customer impact?

Accepted Answer

Utilize AWS X-Ray and Amazon CloudWatch Alarms to quickly identify the specific service or code path experiencing performance bottlenecks and implement a targeted hotfix or configuration adjustment based on the findings.

Question 16

A development team is building a new customer-facing application that processes personally identifiable information (PII). They are concerned about meeting stringent regulatory compliance requirements that mandate robust encryption for data at rest and secure communication channels for data in transit. The application will leverage AWS Lambda functions to process data, storing the processed information in Amazon S3. The team needs to implement a strategy that provides strong data protection, granular access control over encryption keys, and auditable logging of key usage, while also ensuring all inter-service communications are encrypted. Which combination of AWS services and configurations best addresses these requirements?

Accepted Answer

Utilize AWS KMS with customer-managed keys to encrypt data stored in Amazon S3, and ensure all Lambda function outbound network traffic is configured to use TLS.

Question 17

A development team is building a customer-facing web application utilizing AWS Lambda functions for its backend. The application needs to persist user profile information, including preferences and recent activity logs, and also manage temporary session data for authenticated users. The traffic patterns are highly variable, with significant spikes during peak hours, requiring a solution that can scale seamlessly and provide consistent low-latency access to this data. Which AWS data storage service would be most appropriate for efficiently handling both persistent user preferences and ephemeral session state in this serverless architecture, ensuring both scalability and performance under fluctuating loads?

Accepted Answer

Amazon DynamoDB

Question 18

A team is developing a critical financial transaction processing system that relies on a microservices architecture. They are using Amazon SQS to queue incoming transaction requests and Amazon SNS to fan out notifications about transaction status changes to various subscriber services. A key requirement is to prevent duplicate processing of transactions, even in the event of transient failures or restarts of consumer services. The current implementation uses standard SQS queues, which offer at-least-once delivery. Which AWS service, when integrated with the existing architecture, offers the most robust and scalable solution for achieving exactly-once processing semantics for these financial transactions, ensuring data integrity and preventing financial discrepancies?

Accepted Answer

AWS Step Functions, by orchestrating the transaction processing workflow and incorporating unique transaction identifiers for idempotency checks within each state.

Question 19

A team is developing a collaborative real-time editing application that utilizes Amazon DynamoDB to store document content. Multiple users can edit the same document simultaneously. To prevent data loss due to concurrent writes where one user\'s changes might overwrite another\'s without awareness, what strategy should the development team implement to ensure that updates to a specific document item are atomic and that conflicting modifications are handled gracefully, allowing for retries with the latest data?

Accepted Answer

Implement conditional writes in DynamoDB, leveraging a version attribute within the document item. Each read operation retrieves the current version, and update operations include a condition expression verifying that the retrieved version matches the item's current version in the table, incrementing the version upon successful update.

Question 20

Consider a scenario where an AWS Lambda function, triggered by asynchronous notifications from an Amazon S3 bucket, is responsible for updating a specific counter within a single Amazon DynamoDB item. Due to the high volume of object uploads, multiple Lambda function instances can be invoked concurrently, each attempting to increment the counter. Without appropriate safeguards, this could lead to lost updates as concurrent invocations might read the same initial counter value before any instance has a chance to write its updated value back to DynamoDB. Which AWS service feature or pattern would most effectively address the potential for lost updates in this specific scenario?

Accepted Answer

Employing DynamoDB conditional writes to ensure the update operation only succeeds if the item's current version number matches an expected value.

Question 21

A critical microservice relies on an AWS Lambda function to process incoming data payloads. This Lambda function has been provisioned with a reserved concurrency setting of 50. The upstream system utilizes Amazon Simple Queue Service (SQS) to buffer these payloads, and the SQS queue is configured to trigger the Lambda function. If the SQS queue experiences an instantaneous influx of 100 messages, what is the most probable immediate outcome regarding the Lambda function\'s execution and subsequent message handling?

Accepted Answer

Fifty Lambda function instances will execute concurrently, while the remaining fifty will be throttled and subsequently retried by SQS.

Question 22

A startup is developing a real-time collaborative platform that serves users across North America, Europe, and Asia. The application relies heavily on a DynamoDB table to store user profiles, real-time activity logs, and shared document metadata. To ensure a seamless user experience, the platform must provide low-latency data access and high availability, regardless of the user\'s geographic location. Data consistency across all regions is paramount, as concurrent edits to shared documents must be reflected accurately and promptly. Which AWS strategy would best achieve these requirements for their DynamoDB data?

Accepted Answer

Implement DynamoDB Global Tables to replicate data across multiple AWS regions, ensuring low-latency reads and writes and automatic data synchronization.

Question 23

A distributed team of developers is tasked with enhancing a critical microservice responsible for real-time inventory updates for a global online retailer. The service, deployed on AWS ECS using Fargate, has recently exhibited unpredictable failures during periods of high user concurrency. These failures appear to be correlated with the deployment of new container images, where the transition process seems to overload existing resources or introduce network inconsistencies. The team requires a deployment methodology that ensures high availability, allows for thorough testing of the new version before it handles live traffic, and provides a swift rollback mechanism in case of unforeseen issues. Which AWS service and deployment strategy would best address these requirements, promoting adaptability and minimizing disruption during the transition?

Accepted Answer

AWS CodeDeploy with a Blue/Green deployment strategy

Question 24

A development team is tasked with building a real-time financial data processing pipeline. The pipeline must ingest a variable stream of market data, perform complex calculations, and store the results for immediate access by downstream applications. The team anticipates frequent changes to data formats from various sources and fluctuating ingestion rates, requiring a highly adaptable and resilient architecture. They also need to ensure that each data record is processed reliably and that a clear audit trail of transformations is maintained. Which AWS service combination best addresses these requirements for both behavioral adaptability and technical proficiency in handling dynamic data streams and ensuring data integrity?

Accepted Answer

Amazon Kinesis Data Streams integrated with AWS Lambda for processing, and Amazon DynamoDB for storing processed results.

Question 25

A distributed application, architected for high availability across multiple AWS Availability Zones, is experiencing sporadic failures when retrieving critical configuration files stored in an Amazon S3 bucket. These failures manifest as timeouts and connection errors, impacting the application\'s stability during peak operational hours. The development team needs to implement a solution that enhances the reliability and performance of accessing these files without requiring significant changes to the application\'s core logic for fetching data from S3.

Which AWS service, when integrated with the existing S3 bucket, would most effectively address these intermittent retrieval issues by providing a globally distributed caching layer and a more resilient access path?

Accepted Answer

Amazon CloudFront with the S3 bucket configured as the origin

Question 26

A critical microservice, powered by an AWS Lambda function with a reserved concurrency of 50, is experiencing intermittent failures during peak operational hours. Analysis of CloudWatch logs reveals a consistent pattern of `TooManyRequestsException` errors, indicating that the rate of incoming synchronous invocations is frequently exceeding the function\'s allocated concurrency. The business stakeholders require uninterrupted service availability, even during these unpredictable traffic surges, and have expressed a need for the development team to exhibit greater adaptability in managing such load variations. Which architectural adjustment would best address the immediate issue while demonstrating proactive problem-solving and flexibility in handling dynamic demand?

Accepted Answer

Increase the reserved concurrency for the Lambda function to 100.

Question 27

A team is developing a customer-facing analytics dashboard application deployed on Amazon EC2 instances behind an Application Load Balancer (ALB). Users are reporting sporadic periods where the dashboard becomes unresponsive, though the underlying EC2 instances appear healthy according to basic system metrics. The application code has been reviewed and appears to be functioning correctly under normal load. The development team suspects the issue might be related to how the ALB is managing traffic or its health checks. Considering the need for adaptability and effective problem-solving in a cloud environment, what is the most appropriate initial action for a developer to take to diagnose this intermittent issue?

Accepted Answer

Review the Application Load Balancer's target group health check configuration and logs to identify any patterns of unhealthy instances or misconfigured thresholds.

Question 28

A development team is building a serverless application utilizing AWS Lambda to process messages from an Amazon Simple Queue Service (SQS) queue. The Lambda function is configured with an event source mapping where the `batchSize` is set to 10 and `maximumRetryAttempts` is explicitly set to 0. The business mandate is to guarantee that no messages are lost, even in the face of intermittent processing failures within the Lambda function. The SQS queue has a configured Dead-Letter Queue (DLQ) with a `maxReceiveCount` of 5. How should the Lambda function be designed to adhere to the \"no message loss\" requirement under these specific configurations?

Accepted Answer

The Lambda function should acknowledge the entire batch of messages only if all 10 messages within that batch are processed successfully. If any message fails, the function should catch the error, log the problematic message, and exit without acknowledging the batch.

Question 29

A development team is building a new microservices-based e-commerce platform on AWS. A critical business requirement is to ensure that when a customer places an order, the inventory count for the ordered items is accurately decremented, payment is processed, and a confirmation notification is sent to the customer. This entire process must be resilient to transient failures in individual services or network disruptions, maintaining data consistency and providing visibility into the workflow\'s progress. Which AWS service is best suited for orchestrating this multi-step, stateful business process to ensure reliability and fault tolerance?

Accepted Answer

AWS Step Functions

Question 30

When designing an IAM policy for a microservice deployed via AWS Elastic Beanstalk that needs to upload, retrieve, and delete objects from a specific S3 bucket named `user-content-bucket-prod`, which of the following IAM policy statements, when attached to the service\'s execution role, most effectively enforces the principle of least privilege by granting only the necessary S3 permissions?

Accepted Answer

A policy explicitly allowing `s3:PutObject`, `s3:GetObject`, and `s3:DeleteObject` actions on the `arn:aws:s3:::user-content-bucket-prod/*` resource, and implicitly denying all other S3 actions.

AWS Certified Developer Associate 2018 AWS Certified Developer Associate 2018 Free Practice Test — 30 Questions

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