Amazon AWS Certified Developer – Associate DVA-C02 Exam Dumps and Practice Test Questions Set 9 Q161-180

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Question 161 

A developer needs a fully managed key-value store that provides millisecond latency and seamless scaling for a serverless application. Which service should they choose?

A) Amazon DynamoDB
B) Amazon RDS
C) Amazon ElastiCache
D) Amazon Redshift

Answer:  A) Amazon DynamoDB

Explanation: 

Amazon DynamoDB is a fully managed NoSQL key-value and document database that provides single-digit millisecond performance at any scale. It is designed for applications requiring consistently fast reads and writes with seamless scaling, high availability, and built-in security features such as encryption at rest and IAM access control. DynamoDB is widely used in serverless architectures because it integrates directly with AWS Lambda, Amazon API Gateway, and other event-driven services without requiring provisioning or managing infrastructure.

Amazon RDS is a relational database service designed for structured relational workloads. While powerful for SQL-based applications, it does not provide the same low-latency scaling model as DynamoDB and requires management of DB instances, maintenance windows, and connection pools. It is not serverless by default unless using Aurora Serverless, which is not a key-value store.

Amazon ElastiCache offers in-memory caching using Redis or Memcached, providing microsecond latency. However, it is intended primarily as a cache layer and not as a primary durable data store. ElastiCache stores data in memory and does not provide the same durability guarantees as DynamoDB unless additional replication, snapshotting, or failover is configured. It is complementary to a database, not a replacement for persistent storage.

Amazon Redshift is a data warehousing service designed for analytics, not transactional workloads. It handles complex queries across large datasets and supports BI and OLAP workloads. Redshift is not suitable for real-time transactional key-value access, nor is it serverless in the same way DynamoDB is.

DynamoDB is the correct choice because it offers fully managed operations, automatic scaling, durable data storage, event-driven triggers through DynamoDB Streams, and predictable performance. It allows developers to build serverless applications without provisioning servers or worrying about replication, high availability, or throughput adjustments. Its integration with on-demand capacity modes, transactions, TTL, Streams, and Accelerator (DAX) make it ideal for mission-critical, low-latency key-value workloads.

Question 162 

A developer wants to deploy a Docker container without managing servers or clusters. Which AWS service should they use?

A) Amazon ECS with Fargate
B) Amazon EC2
C) Amazon EKS
D) AWS Lambda

Answer:  A) Amazon ECS with Fargate

Explanation:

Amazon ECS with AWS Fargate is a fully managed serverless compute engine for containerized applications. It allows developers to run Docker containers without provisioning or managing underlying EC2 instances, clusters, or servers. Fargate handles launch, scaling, patching, and resource allocation automatically, and developers only specify CPU, memory, networking, and task definitions. This makes it ideal for teams that want the flexibility of containers without operational overhead.

Amazon EC2 requires provisioning virtual machines, managing AMIs, patching, scaling groups, and instance lifecycle operations. Although EC2 can run containers using ECS or manually installed Docker, the user is still responsible for maintaining the infrastructure. This contradicts the requirement of avoiding server management entirely.

Amazon EKS (Elastic Kubernetes Service) allows developers to run Kubernetes clusters in AWS. While powerful and flexible, Kubernetes adds significant operational complexity and requires management of nodes, control planes (even if partially managed), and cluster configurations. EKS is not serverless by default unless combined with Fargate, but the question specifies the simplest option without cluster management.

AWS Lambda supports container images as deployment artifacts but is designed for short-lived serverless functions rather than long-running container applications. It includes strict runtime limits and event-driven invocation rather than acting as a general-purpose container runtime.

ECS with Fargate is correct because it provides a true serverless container experience, minimal operational overhead, and seamless integration with AWS services. It scales automatically, supports both Linux and Windows containers, and offers secure isolation by design.

Question 163 

A developer needs to validate inbound API requests and ensure that only properly formatted payloads hit the backend Lambda function. Which service provides built-in request validation?

A) Amazon API Gateway
B) AWS Lambda
C) AWS WAF
D) Amazon CloudFront

Answer:  A) Amazon API Gateway

Explanation:

Amazon API Gateway includes built-in request validation features that allow developers to enforce schemas, verify required fields, check data types, and validate request structure before sending data to the backend. This lowers unnecessary Lambda invocations, reduces cost, and ensures that only properly formatted requests reach the application logic. Developers can use OpenAPI definitions or API Gateway models to define expected request bodies, path parameters, headers, and query strings.

AWS Lambda can validate data internally, but doing so means invalid requests still invoke the function, increasing cost and adding unnecessary overhead. Lambda has no built-in request validation mechanism; validation must be implemented manually in code.

AWS WAF provides protection against malicious web traffic such as SQL injection or cross-site scripting (XSS). While it can filter requests based on patterns, IPs, and rules, it does not validate JSON payloads or enforce API schemas. It is designed for security at the network and application layer rather than request structure validation.

Amazon CloudFront is a CDN service that caches and accelerates HTTP/HTTPS content delivery. It does not provide request validation for API payloads. While CloudFront can integrate with API Gateway and WAF, validation of API payloads must happen at the API layer.

API Gateway is the correct answer because it offers first-class support for validating incoming API requests using schema models, enabling developers to enforce consistency, reduce unnecessary compute usage, and simplify backend logic. It supports validation for both REST and HTTP APIs and helps ensure that downstream services receive clean, expected request formats.

Question 164 

A developer is building an event-driven architecture and needs to route events between AWS services with filtering and transformation capabilities. Which service should be used?

A) Amazon EventBridge
B) Amazon SNS
C) Amazon SQS
D) AWS Lambda

Answer:  A) Amazon EventBridge

Explanation: 

Amazon EventBridge is a serverless event bus service designed specifically to route events between AWS services, SaaS applications, and custom event producers. It supports content-based filtering, event transformation using input transformers, event schema discovery, and flexible routing rules. EventBridge is ideal for event-driven architectures that require fine-grained control over event flows, decoupled components, and scalable event ingestion.

Amazon SNS is a pub/sub messaging system that broadcasts messages to subscribers such as Lambda functions, SQS queues, or HTTP endpoints. While it supports basic filtering using message attributes, it lacks advanced routing rules and transformation capabilities that EventBridge provides. SNS is better suited for fan-out messaging patterns, not complex event routing.

Amazon SQS is a message queue used for decoupling producers and consumers. It stores messages until they are processed, ensuring reliable delivery. However, SQS does not route events, transform data, or support pattern matching. It is optimized for asynchronous communication rather than event pipelines.

AWS Lambda executes code in response to triggers but is not designed to route or manage events across multiple services. Lambda acts as a compute engine within an event-driven architecture but is not the event bus itself.

EventBridge is correct because it enables developers to build scalable, decoupled event-driven applications with sophisticated routing, filtering, and transformation capabilities. It reduces complexity, avoids tight coupling, and supports integrations with a wide range of AWS and external services.

Question 165 

A developer needs a durable, scalable message queue that guarantees at-least-once delivery for microservices. Which service fits this requirement?

A) Amazon SQS
B) Amazon SNS
C) Amazon Kinesis Data Streams
D) AWS Step Functions

Answer:  A) Amazon SQS

Explanation: 

Amazon SQS is a fully managed message queuing service that provides at-least-once delivery, durability through multi-AZ replication, and the ability to decouple microservices. It supports both Standard and FIFO queues, enabling applications to handle variable workloads while ensuring reliable delivery. SQS is designed for asynchronous communication, buffering messages between producers and consumers without requiring them to operate at the same rate.

Amazon SNS is a pub/sub notification system that immediately pushes messages to subscribers such as HTTP endpoints, Lambda functions, or SQS queues. SNS does not provide message durability in the same way SQS does, nor does it temporarily store messages for processing. It is not a queueing system and does not guarantee ordered or delayed processing.

Amazon Kinesis Data Streams is optimized for real-time streaming data pipelines, supporting high-throughput ingestion from multiple producers. While it stores data temporarily for multiple consumers, it is not a message queue designed for microservice communication. Kinesis is ideal for streaming analytics, telemetry, and event processing, not general-purpose queueing.

AWS Step Functions orchestrate workflows and state machines but are not designed for message buffering or asynchronous communication. They coordinate tasks but do not provide durable queued message storage between distributed components.

SQS is the correct answer because it delivers durable, scalable, and reliable message queuing for distributed applications, ensuring at-least-once delivery and decoupled microservice architecture.

Question 166 

A developer needs to automatically deploy Lambda functions, API Gateway, and DynamoDB tables using infrastructure as code. Which service should they use?

A) AWS CloudFormation
B) AWS CodeCommit
C) Amazon ECS
D) Amazon Cognito

Answer:  A) AWS CloudFormation

Explanation: 

AWS CloudFormation is an infrastructure-as-code service that enables developers to define and provision AWS resources declaratively through JSON or YAML templates. This allows infrastructure components such as Lambda functions, API Gateway APIs, DynamoDB tables, IAM roles, and other AWS services to be deployed automatically. CloudFormation manages dependencies between resources, so you can reliably create, update, or delete stacks in a controlled manner. Additionally, it supports stack updates, drift detection, and rollback, which ensures consistent deployments across multiple environments.

AWS CodeCommit is a fully managed version control service that hosts secure Git repositories. Developers use it to store application code, including CloudFormation templates, but it does not itself provision or deploy resources. While CodeCommit integrates with CI/CD pipelines, its primary function is code storage and versioning rather than automated infrastructure deployment.

Amazon ECS is a container orchestration service for running and managing Docker containers at scale. ECS manages containerized applications on clusters of EC2 instances or Fargate without needing to manage infrastructure directly. While ECS is suitable for deploying container workloads, it is not designed for deploying serverless components like Lambda functions, API Gateway APIs, or DynamoDB tables as part of an infrastructure-as-code solution.

Amazon Cognito is a user authentication and identity management service. It handles sign-up, sign-in, and access control for web and mobile applications but does not provision or manage infrastructure. Cognito is focused on application security rather than automation of resource deployment.

CloudFormation is the correct choice because it provides declarative templates that define the desired state of resources. Its tight integration with other AWS services allows developers to deploy serverless applications consistently and repeatedly, automate dependency handling, and maintain a clear history of infrastructure changes.

Question 167 

A developer wants to build a fully managed GraphQL API with real-time data subscriptions. Which service should they choose?

A) AWS AppSync
B) Amazon API Gateway
C) Amazon RDS
D) AWS Lambda

Answer:  A) AWS AppSync

Explanation:

AWS AppSync is a fully managed service that enables developers to build GraphQL APIs with real-time updates through subscriptions. AppSync integrates seamlessly with DynamoDB, Lambda, OpenSearch, and other AWS data sources, allowing for low-latency queries and mutations. It also handles conflict resolution and offline caching for mobile clients, making it ideal for applications that need synchronized real-time data across multiple devices. AppSync automatically manages schema validation, resolvers, and scaling, reducing the operational overhead of building a GraphQL backend.

Amazon API Gateway is a service for creating RESTful and WebSocket APIs. While it can technically be used to expose GraphQL endpoints, it does not natively support GraphQL features like schema management, resolvers, or real-time subscriptions. Implementing a fully functional GraphQL API on API Gateway would require significant custom development and Lambda integration.

Amazon RDS is a managed relational database service. It is used to store structured data but does not provide API management, schema resolution, or real-time subscriptions. RDS alone cannot handle GraphQL queries or synchronize updates across clients in real-time.

AWS Lambda is a serverless compute service that runs code in response to events. While Lambda can be used as a resolver or backend for a GraphQL API, it does not offer the fully managed GraphQL features or real-time subscription capabilities that AppSync provides. Using Lambda alone would require manual orchestration and additional code.

AppSync is the correct choice because it provides a fully managed GraphQL service that includes real-time subscriptions, automatic scaling, schema management, and integration with multiple backend data sources. It is designed to minimize development and operational complexity for real-time, synchronized APIs.

Question 168 

A company wants to detect and block suspicious API activity such as SQL injection or malicious patterns. Which service helps protect APIs at the edge?

A) AWS WAF
B) Amazon GuardDuty
C) AWS Shield
D) AWS CloudTrail

Answer:  A) AWS WAF

Explanation:

AWS WAF is a web application firewall that enables developers and security teams to filter HTTP and HTTPS traffic based on customizable rules. It protects applications from common web exploits such as SQL injection, cross-site scripting, and bot attacks. WAF integrates with CloudFront, API Gateway, and Application Load Balancers, providing protection at the network edge and reducing latency while blocking malicious requests before they reach backend services.

Amazon GuardDuty is a threat detection service that continuously monitors AWS accounts and workloads to identify malicious or unauthorized behavior. While it can detect compromised resources and suspicious API activity, GuardDuty does not block traffic directly. It is more of an alerting and investigation tool than a prevention service.

AWS Shield provides managed Distributed Denial of Service (DDoS) protection for applications hosted on AWS. While Shield protects against volumetric attacks and ensures availability, it does not provide fine-grained, application-level traffic filtering for attacks like SQL injection or API misuse.

AWS CloudTrail records API calls across AWS accounts for auditing and compliance purposes. It captures information about API requests but does not actively block or filter traffic, so it cannot prevent attacks in real-time.

AWS WAF is the correct answer because it operates at the application layer, providing rule-based filtering to detect and block malicious requests before they reach the backend. It is customizable, scalable, and integrated with key AWS services, making it ideal for protecting APIs at the edge.

Question 169 

A developer needs to orchestrate multiple Lambda functions into a workflow with retries, parallel execution, and state management. Which service should they use?

A) AWS Step Functions
B) AWS Lambda
C) Amazon SQS
D) Amazon API Gateway

Answer:  A) AWS Step Functions

Explanation:

AWS Step Functions is a serverless orchestration service that enables developers to coordinate multiple AWS services into complex workflows. Step Functions allows sequential and parallel execution of tasks, supports retries and error handling, and maintains state across steps. Workflows are defined using Amazon States Language (ASL), and developers can visualize execution and troubleshoot failures easily. Step Functions integrates seamlessly with Lambda, ECS, DynamoDB, and other AWS services, making it ideal for building reliable distributed workflows.

AWS Lambda is a compute service that executes code in response to events. While Lambda is powerful for processing individual tasks, it does not provide native workflow orchestration, state management, or retries across multiple functions. Developers would need to manually implement orchestration logic.

Amazon SQS is a message queuing service that decouples application components and supports asynchronous communication. While it facilitates reliable message delivery, it does not provide workflow orchestration, state tracking, or parallel execution for tasks.

Amazon API Gateway exposes REST and WebSocket APIs but does not manage multi-step workflows or handle task state. It is useful for communication between clients and services but cannot orchestrate serverless tasks.

Step Functions is the correct choice because it provides full orchestration of distributed workflows, including retries, parallel processing, error handling, and state management. It simplifies complex workflow automation in serverless applications while providing visibility into each step’s execution.

Question 170 

A developer wants to generate temporary AWS credentials for a mobile application user without exposing permanent keys. Which service should they use?

A) Amazon Cognito
B) AWS IAM
C) AWS Secrets Manager
D) AWS KMS

Answer:  A) Amazon Cognito

Explanation:

Amazon Cognito allows developers to generate temporary AWS credentials for mobile and web application users using identity pools. These credentials can be scoped to specific permissions and automatically expire, reducing the risk of exposing permanent access keys in client applications. Cognito integrates with social identity providers, SAML, and custom authentication systems, and supports both authenticated and unauthenticated users.

AWS IAM manages users, groups, roles, and policies in AWS accounts. While IAM roles and policies define permissions, IAM does not directly issue temporary credentials to end users for client-side applications. Developers would need to implement additional logic to generate short-lived credentials securely.

AWS Secrets Manager is a service for storing and rotating secrets such as database passwords and API keys. It does not issue temporary AWS credentials to mobile or web clients, although it can provide secrets to applications running in secure environments.

AWS KMS manages encryption keys for data protection and cryptographic operations. It does not handle authentication, access management for mobile applications, or temporary credentials issuance.

Amazon Cognito is the correct choice because it securely provides temporary, limited-privilege AWS credentials for mobile and web applications, enabling safe access to AWS services without embedding long-term keys in clients.

Question 171 

A developer wants to inspect API calls and troubleshoot latency issues across microservices. Which service provides distributed tracing?

A) AWS X-Ray
B) Amazon CloudWatch Logs
C) AWS CloudTrail
D) AWS Config

Answer:  A) AWS X-Ray

Explanation:

AWS X-Ray provides distributed tracing for microservices, capturing data about requests as they travel through services. It records segments and subsegments of requests, performance metrics, errors, and downstream service calls. Developers can visualize call graphs, identify bottlenecks, and analyze latency patterns across distributed applications. X-Ray integrates with Lambda, API Gateway, ECS, and other services to provide end-to-end visibility.

Amazon CloudWatch Logs collects and stores log data from applications, systems, and AWS services. While it helps troubleshoot errors and monitor log events, it does not automatically correlate requests across multiple services or provide trace visualizations.

AWS CloudTrail records API activity for auditing and compliance, tracking who accessed AWS resources and when. It does not capture request-level performance metrics or visualize application latency.

AWS Config monitors configuration changes and compliance but does not track request flows or measure latency across services. It is intended for auditing infrastructure, not distributed application performance.

AWS X-Ray is the correct choice because it allows developers to trace individual requests, identify performance bottlenecks, and troubleshoot errors in complex microservices architectures.

Question 172 

A developer wants to build a real-time leaderboard for a gaming app using an in-memory data store with extremely low latency. Which service is most suitable?

A) Amazon ElastiCache for Redis
B) Amazon DynamoDB
C) Amazon RDS
D) Amazon S3

Answer:  A) Amazon ElastiCache for Redis

Explanation:

Amazon ElastiCache for Redis is an in-memory key-value data store optimized for microsecond-level latency. It is ideal for real-time leaderboards, counters, session stores, and caching, as it provides data structures such as sorted sets, which can maintain rankings efficiently. Redis supports atomic operations and fast updates, making it suitable for dynamic, high-traffic applications like gaming.

Amazon DynamoDB is a managed NoSQL database that provides single-digit millisecond latency. While it is fast and scalable, it cannot achieve the microsecond latency of Redis for real-time ranking, and additional logic is required to implement sorted sets.

Amazon RDS is a managed relational database suitable for structured data and transactional workloads. It provides durability and consistency but is too slow for microsecond updates required for real-time leaderboards.

Amazon S3 is object storage for static files and backups. It cannot support the low-latency operations or atomic updates needed for live leaderboards.

ElastiCache for Redis is the correct choice because it provides high-speed, in-memory operations and data structures specifically optimized for real-time leaderboard applications.

Question 173 

A developer needs to run scheduled tasks such as cleaning up logs or triggering daily reports in a serverless application. Which service is ideal?

A) Amazon EventBridge Scheduler
B) AWS Lambda
C) Amazon SQS
D) Amazon EC2

Answer:  A) Amazon EventBridge Scheduler

Explanation:

Amazon EventBridge Scheduler allows developers to trigger events at specified times, running tasks such as invoking Lambda functions, Step Functions workflows, or API endpoints. It eliminates the need to maintain servers or cron jobs and supports precise scheduling, repeat intervals, and complex patterns. EventBridge Scheduler is serverless and scales automatically to handle thousands of scheduled events without operational overhead.

AWS Lambda executes code in response to events but does not provide built-in scheduling. Developers would need to pair it with EventBridge or an external scheduler to run tasks on a schedule.

Amazon SQS provides message queuing for decoupled components but cannot schedule events or trigger tasks at specific times. It is not a scheduling service.

Amazon EC2 provides compute resources that could run cron jobs, but this approach requires managing instances, operating systems, scaling, and availability, which increases operational complexity and cost.

EventBridge Scheduler is the correct service because it provides serverless, scalable, and precise scheduling for tasks without requiring infrastructure management.

Question 174

A developer needs to deliver static website content globally with low latency. Which service should they use?

A) Amazon CloudFront
B) Amazon S3
C) AWS Lambda@Edge
D) Amazon EC2

Answer:  A) Amazon CloudFront

Explanation:

Amazon CloudFront is a global content delivery network (CDN) designed to deliver both static and dynamic content to end users with low latency and high performance. It works by caching content at edge locations around the world, which allows requests to be served from a location geographically closer to the user rather than the origin server. This distributed architecture reduces network latency, decreases load on the origin, and improves overall responsiveness for websites, APIs, and media streaming. CloudFront also supports features such as HTTPS, content compression, and caching policies, ensuring secure and efficient content delivery.

Amazon S3 is commonly used to host static websites and stores content such as HTML, CSS, JavaScript, images, or videos. While it is reliable and scalable for storing static content, S3 alone does not provide a global caching mechanism. Users located far from the S3 bucket’s region may experience slower load times due to increased latency. Without a CDN like CloudFront, delivering content to a global audience can result in inconsistent performance and a less responsive user experience.

AWS Lambda@Edge complements CloudFront by enabling developers to run custom logic at edge locations. This allows for advanced features like URL rewriting, authentication, header manipulation, or A/B testing close to the user, reducing the need to route requests back to the origin. However, Lambda@Edge does not deliver content independently. It works in conjunction with CloudFront to modify or enhance requests and responses at the edge, rather than functioning as a standalone content delivery solution.

Amazon EC2 can be used to host websites by running web servers on virtual machines, but this approach requires managing the underlying infrastructure, including scaling, patching, and network configuration. Hosting a static website solely on EC2 is less efficient and more expensive compared to a combination of S3 and CloudFront, especially when the goal is global, low-latency access. EC2 is better suited for dynamic, compute-intensive applications rather than serving static content globally.

CloudFront is the ideal service for globally delivering static website content because it combines worldwide caching, low latency, security, and integration with other AWS services. By distributing content closer to end users and supporting edge optimizations, CloudFront ensures fast, reliable, and scalable delivery, making it the preferred choice for static website hosting with a global reach.

Question 175 

A developer needs a fully managed, autoscaling relational database compatible with MySQL. Which service should they choose?

A) Amazon Aurora
B) Amazon DynamoDB
C) Amazon Redshift
D) Amazon Neptune

Answer:  A) Amazon Aurora

Explanation: 

Amazon Aurora is a fully managed relational database compatible with MySQL and PostgreSQL. It provides high performance, fault tolerance, and autoscaling capabilities. Aurora automatically replicates data across multiple Availability Zones for durability, supports automated backups, and integrates with other AWS services. It is suitable for transactional workloads that require relational features such as complex queries and ACID compliance.

Amazon DynamoDB is a NoSQL database optimized for key-value and document workloads. While it is highly scalable and low latency, it does not support relational operations or SQL-compatible queries needed for MySQL applications.

Amazon Redshift is a data warehouse service for analytical workloads. It is optimized for large-scale analytics rather than transactional relational applications, and it does not provide MySQL compatibility.

Amazon Neptune is a managed graph database designed for storing and querying graph data. It does not support MySQL or general relational workloads.

Aurora is the correct choice because it provides a fully managed, autoscaling, MySQL-compatible relational database with high availability, performance, and ease of management.

Question 176 

A developer requires a serverless queue that automatically scales to zero when not in use and supports near-real-time messaging. Which service should they choose?

A) Amazon SQS
B) Amazon SNS
C) Amazon MQ
D) AWS Lambda

Answer:  A) Amazon SQS

Explanation:

Amazon SQS (Simple Queue Service) is a fully managed message queuing service designed for serverless and distributed application architectures. One of its main advantages is that it automatically scales according to workload, including scaling down to zero when there are no messages in the queue. This makes it cost-efficient for workloads that have intermittent traffic. SQS ensures reliable message delivery by allowing producers to send messages that consumers can process asynchronously, providing decoupling between components and improving system resilience.

Amazon SNS (Simple Notification Service) is a pub/sub messaging service that pushes notifications to subscribers. While SNS supports near-real-time messaging, it is fundamentally different from a queue because it broadcasts messages to multiple subscribers instead of storing them until processed. This means it cannot provide the same guaranteed, decoupled, and reliable delivery semantics as SQS, particularly for systems that require message persistence.

Amazon MQ is a managed message broker service compatible with ActiveMQ and RabbitMQ. It offers traditional queue and topic messaging but requires managing a broker infrastructure, including scaling, patching, and high availability configurations. Unlike SQS, it is not fully serverless and does not scale automatically to zero, making it less ideal for serverless architectures where minimal operational overhead is desired.

AWS Lambda is a serverless compute service that executes code in response to triggers or events. Lambda itself does not act as a message queue. Although it can process messages from SQS or SNS, it cannot persist or store messages for later retrieval.

SQS is the correct choice because it combines serverless operation, automatic scaling, message persistence, and decoupled communication. These features make it ideal for near-real-time, reliable messaging without requiring the developer to manage underlying infrastructure. It is particularly suitable for microservices architectures where queues act as buffers between producers and consumers.

Question 177 

A developer wants to upload large objects to S3 with fault tolerance during transmission. Which technique should they use?

A) S3 multipart upload
B) S3 standard upload
C) S3 Transfer Acceleration
D) Pre-signed URLs

Answer:  A) S3 multipart upload

Explanation:

S3 multipart upload is a specialized method for efficiently uploading large objects to Amazon S3. Instead of sending a file in a single operation, multipart upload splits it into smaller, independently transferable parts. Each part can be uploaded separately, and if a failure occurs during transmission, only the affected part needs to be retried rather than restarting the entire upload. This capability greatly improves fault tolerance and ensures that large files—especially those spanning multiple gigabytes—can be uploaded reliably even in environments with intermittent network connectivity. Multipart upload also supports parallel uploads, allowing multiple parts to be sent simultaneously, which maximizes available bandwidth and reduces overall transfer time, making it highly suitable for production workloads.

S3 standard upload, in contrast, handles files in a single, continuous operation. While this method works well for small objects, it is not optimized for large files. If the upload fails at any point, the operation must be restarted from the beginning, which increases the risk of failed transfers and can be inefficient for very large objects. In scenarios where large datasets or multi-gigabyte files are involved, using a single-step upload can lead to wasted time, repeated failures, and a poor user experience, highlighting why multipart upload is preferred for these use cases.

S3 Transfer Acceleration is a feature designed to improve upload speed by routing traffic through Amazon CloudFront edge locations. This reduces latency and improves performance for geographically distributed clients. However, Transfer Acceleration does not inherently address the fault tolerance or retry mechanisms that multipart upload provides. In practice, many developers combine Transfer Acceleration with multipart upload to achieve both faster transfers and greater reliability when uploading large files. While acceleration enhances throughput, it does not replace the core functionality of multipart upload in managing large file reliability.

Pre-signed URLs provide temporary access to upload or download objects without exposing AWS credentials. They are useful for delegating permissions to clients securely and controlling access. However, pre-signed URLs do not address challenges related to uploading large files or retrying failed transfers. They simply grant time-limited access and must be used in conjunction with proper upload methods to handle large objects efficiently.

Multipart upload is the correct solution because it directly tackles the challenges of uploading large objects reliably. By enabling independent retries for failed parts and supporting parallel transmission, it minimizes the risk of upload failures and reduces the operational overhead of network interruptions. Combined with features like Transfer Acceleration or pre-signed URLs, multipart upload ensures both reliability and performance for large-scale production workloads, making it the best choice for handling large objects in Amazon S3.

Question 178 

A developer needs to set environment variables securely in Lambda without exposing secrets. Which service should be used?

A) AWS Secrets Manager
B) Amazon SQS
C) AWS CloudTrail
D) Amazon EFS

Answer:  A) AWS Secrets Manager

Explanation:

AWS Secrets Manager is a fully managed service for storing, retrieving, and rotating secrets securely. It allows developers to store sensitive information such as API keys, database credentials, and tokens. Secrets Manager can integrate with Lambda, injecting secrets at runtime without hardcoding sensitive values in the function’s environment variables. Additionally, it supports automatic secret rotation, reducing the risk of security breaches caused by expired or compromised credentials.

Amazon SQS is a message queuing service and is not designed for storing secrets. While SQS can carry messages containing sensitive information, it does not provide secure storage, automatic rotation, or encryption management, which are critical for managing secrets safely.

AWS CloudTrail is an auditing and monitoring service that records API activity in an AWS account. CloudTrail helps with compliance and operational troubleshooting but does not store or inject secrets into applications. Its focus is on logging events rather than securely managing sensitive data.

Amazon EFS (Elastic File System) is a network file system used to store persistent data. While it provides storage, it is not optimized for secret management and does not provide features like automated encryption, rotation, or integration with Lambda environment variables.

Secrets Manager is the correct choice because it ensures that sensitive environment variables remain secure, automatically managed, and easily accessible by Lambda at runtime. This allows developers to implement secure, serverless applications without exposing secrets in code or configuration files.

Question 179 

A developer wants to test new Lambda function versions with only a percentage of traffic before full rollout. Which AWS feature supports this?

A) Lambda alias routing
B) Lambda layers
C) Reserved concurrency
D) Step Functions

Answer:  A) Lambda alias routing

Explanation:

Lambda alias routing is a powerful feature that allows developers to create named aliases pointing to specific versions of a Lambda function. An alias can represent a stable production version, a testing version, or any other release stage. One of the most valuable aspects of aliases is their support for weighted traffic shifting, which enables developers to control how much of the incoming request traffic is directed to a particular function version. This makes it possible to implement controlled rollouts, such as sending 10% of traffic to a new version while 90% continues using the stable version. By observing the behavior and performance of the new version under real traffic, developers can identify issues early and reduce the risk of introducing errors to the production environment.

Lambda layers serve a different purpose. Layers allow developers to package libraries, dependencies, or shared code separately from the function code itself. By using layers, multiple functions can share the same libraries without bundling them individually, which reduces deployment package size and improves code modularity. However, layers do not provide any mechanism for routing traffic between function versions or managing phased deployments. They are primarily focused on code organization and reuse rather than deployment strategies.

Reserved concurrency is another Lambda feature, which sets a maximum number of concurrent executions a function can handle. This is useful for controlling resource usage and ensuring that critical functions are not throttled by other workloads, but it does not influence which version of a function handles incoming requests. Reserved concurrency is concerned with scaling and resource allocation rather than deployment or version control.

Step Functions provide orchestration for serverless workflows, coordinating tasks across multiple AWS services such as Lambda, DynamoDB, and ECS. They allow developers to define complex execution sequences, manage retries, and handle failures, but they do not provide any direct mechanism for routing traffic to specific Lambda versions. Step Functions are focused on workflow management rather than deployment strategies.

Alias routing is the correct choice for controlled version deployments because it provides precise traffic control between function versions. Developers can gradually shift traffic to a new version, monitor metrics and logs for performance or errors, and ensure the updated version operates correctly before routing all traffic to it. This staged deployment approach, often referred to as a canary or phased rollout, minimizes risk and improves operational confidence in serverless environments.

Question 180 

A developer needs to store logs that must remain immutable for compliance. Which service provides write-once-read-many (WORM) storage?

A) Amazon S3 Glacier Vault Lock
B) Amazon SQS
C) Amazon RDS
D) AWS Lambda

Answer:  A) Amazon S3 Glacier Vault Lock

Explanation:

Amazon S3 Glacier Vault Lock is a feature designed to provide write-once-read-many (WORM) storage, which is particularly important in scenarios requiring strict compliance and long-term log retention. Vault Lock enables organizations to enforce policies that make data immutable once locked. This immutability ensures that stored logs cannot be altered or deleted, providing a reliable mechanism for meeting regulatory requirements such as SEC Rule 17a-4(f), FINRA, or other industry-specific compliance standards. By using Vault Lock, organizations can confidently store audit logs, financial records, or other critical information knowing that it will remain intact and accessible for the required retention period.

Amazon SQS, or Simple Queue Service, is a managed message queuing service that temporarily holds messages to enable asynchronous processing between distributed components. While SQS ensures reliable delivery and can handle message retries, it is not designed as a long-term storage solution. Messages in SQS are transient and are deleted once consumed, which means it cannot provide immutable storage or meet compliance requirements for write-once-read-many retention of logs.

Amazon RDS, a managed relational database service, allows users to store structured data and define backup retention policies. While RDS can maintain backups and snapshots for recovery purposes, it does not provide true WORM capabilities. Data stored in RDS can still be modified or deleted by users with appropriate permissions, making it unsuitable for scenarios where regulatory compliance requires that logs remain immutable and tamper-proof over time.

AWS Lambda is a serverless compute service that executes code in response to events. Lambda functions are ephemeral by nature, and any logging generated by Lambda is typically written to Amazon CloudWatch Logs or other logging services. While CloudWatch stores logs reliably, it does not inherently provide WORM compliance or immutability guarantees. Therefore, Lambda itself is not a solution for storing compliance-grade immutable logs.

S3 Glacier Vault Lock is the correct solution for immutable, regulatory-compliant log storage because it combines durability, security, and strict enforcement of retention policies. Once a Vault Lock policy is applied, data cannot be modified or deleted until the retention period expires. This ensures that critical logs and records remain tamper-proof, auditable, and compliant with industry regulations. By leveraging Vault Lock, organizations can maintain the integrity of their logs, meet legal and regulatory obligations, and implement secure long-term archival strategies with confidence.