DVA-C02 Development with AWS Services Practice Test 6 — 15 Questions

Question 1

A developer invokes an AWS Lambda function and receives a timeout error. The function is configured with a 3-second timeout. The developer needs to process data that sometimes takes up to 10 seconds. What should the developer do?

Choose an answer to begin — your selection is scored in the full session.

Accepted Answer

Increase the Lambda function timeout to 10 seconds.. The error indicates the Lambda function is timing out because its configured timeout of 3 seconds is insufficient for processing that sometimes takes up to 10 seconds. Option B directly addresses this by increasing the timeout to 10 seconds, which is within the maximum Lambda timeout of 15 minutes (900 seconds). This ensures the function can complete its execution without being prematurely terminated.

Answer

Change the invocation type to Event (async).

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Increase the memory allocation for the Lambda function.

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Set reserved concurrency to 1.

Question 2

A company uses AWS CodeBuild to build and test code. The buildspec.yml includes a pre-build phase that downloads dependencies from a private repository. The developer wants to securely store the credentials for the private repository. Which AWS service should the developer use to store these credentials and reference them in the buildspec?

Accepted Answer

Store the credentials in AWS Systems Manager Parameter Store and reference them in the buildspec.. AWS Systems Manager Parameter Store is the correct choice because it provides secure storage for configuration data and secrets, and CodeBuild natively supports referencing parameters from Parameter Store directly in the buildspec.yml using the 'parameter-store' block under 'env'. While AWS Secrets Manager is also natively supported in CodeBuild, Option B is incorrect because it suggests using the AWS CLI in the build phase to retrieve the secrets, which is an anti-pattern and adds unnecessary complexity compared to native buildspec referencing.

Answer

Store the credentials in an S3 bucket with server-side encryption.

Answer

Store the credentials in AWS Secrets Manager and use the AWS CLI in the build phase to retrieve them.

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Store the credentials in the buildspec.yml file as environment variables.

Question 3

A developer is using AWS CodePipeline to deploy a microservices application to Amazon ECS using the 'Rolling update' deployment type. The pipeline includes a source stage (CodeCommit), build stage (CodeBuild), and deploy stage (CodeDeploy to ECS). After a recent commit, the build stage succeeds, but the deploy stage fails with 'The service has reached the maximum number of running tasks.' What is the MOST likely cause?

Accepted Answer

The task definition is misconfigured and the task fails to start.. During a rolling update deployment in Amazon ECS, the service scheduler uses the `minimumHealthyPercent` and `maximumPercent` parameters to determine how many tasks can be stopped and started:
- `minimumHealthyPercent` represents the lower limit on the number of tasks that must remain running and healthy during a deployment (as a percentage of the desired count).
- `maximumPercent` represents the upper limit on the number of tasks that can be running during a deployment (as a percentage of the desired count).

If both are set to 100% and the desired count is 2:
- Since `minimumHealthyPercent` is 100%, the scheduler must keep at least 2 healthy tasks running at all times. It cannot stop any existing tasks first.
- Since `maximumPercent` is 100%, the scheduler cannot run more than 2 tasks at any time. It cannot start any new tasks first.
This creates a deadlock where the deployment cannot progress and eventually times out. To fix this, `maximumPercent` should be increased (e.g., to 200%) or `minimumHealthyPercent` should be decreased (e.g., to 50%).

Answer

The ECS service is configured with auto scaling and has reached the maximum task count.

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The ECS service has reached the AWS account service quota for Fargate tasks.

Answer

The CodeDeploy deployment configuration uses a 'canary' instead of 'rolling' update.

Question 4

A developer is building a serverless application that processes images uploaded to an S3 bucket. The bucket triggers a Lambda function that creates a thumbnail and stores it in another S3 bucket. The developer notices that the Lambda function is invoked multiple times for the same object, causing duplicate thumbnails. What is the MOST likely cause?

Accepted Answer

S3 event notifications are eventually consistent and may deliver duplicates.. Amazon S3 event notifications are designed to provide at-least-once delivery. This means that while most events are delivered exactly once, duplicate event notifications can occasionally occur. To handle this, the Lambda function should be designed to be idempotent, ensuring that processing the same event multiple times does not cause unintended side effects (like duplicate thumbnails).

Answer

The Lambda function is configured with a DLQ that causes retries.

Answer

The Lambda function is idempotent and should handle duplicates.

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The S3 bucket has multiple event notifications that trigger the same Lambda function.

Question 5

Which TWO AWS services can be used to decouple components of a microservices architecture?

Accepted Answer

Amazon EventBridge. Amazon EventBridge (Option B) is correct because it provides a serverless event bus that decouples microservices by allowing them to communicate asynchronously via events. Services publish events to EventBridge, and other services consume them without direct coupling, enabling loose coupling and scalability.

Answer

Amazon Route 53

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Elastic Load Balancing

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Amazon CloudWatch

Question 6

Which THREE actions can a developer take to improve the cold start latency of an AWS Lambda function?

Accepted Answer

Use a language runtime with faster startup time, such as Python or Node.js.. Python and Node.js use interpreted runtimes with faster initialization times compared to compiled runtimes like Java or .NET. These runtimes have smaller binary sizes and lower startup overhead, reducing the time from invocation to execution start, which directly improves cold start latency.

Answer

Place the Lambda function inside a VPC.

Answer

Increase the function's timeout setting.

Question 7

A company is building a serverless application using AWS Lambda and Amazon API Gateway. The application needs to process user uploads to an S3 bucket. The Lambda function should be invoked only when new objects are created in the bucket. Which service should be used to trigger the Lambda function?

Accepted Answer

Amazon S3 event notifications. Amazon S3 can send event notifications directly to AWS Lambda when new objects are created. Option A (Amazon Kinesis Data Streams) is incorrect because it is used for real-time streaming data, not for triggering Lambda from S3 events directly; it would require additional components. Option C (Amazon CloudWatch Events) is incorrect because it is used for scheduling or responding to AWS resource state changes, not for S3 object creation events directly. Option D (Amazon Simple Queue Service) is incorrect because it requires polling by a consumer, and while S3 can send events to SQS, the question asks for the service that triggers the Lambda function directly; S3 event notifications are the simplest direct integration.

Answer

Amazon Kinesis Data Streams

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Amazon CloudWatch Events

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Amazon Simple Queue Service (SQS)

Question 8

A developer notices that an AWS Lambda function is timing out after 15 seconds. The function makes HTTP requests to an external API. How can the developer resolve this issue without changing the function code?

Accepted Answer

Increase the timeout setting of the Lambda function. The Lambda function is timing out because its configured execution timeout (15 seconds) is too short for the HTTP requests to the external API to complete. Increasing the timeout setting (up to the maximum limit of 15 minutes) allows the function to run longer and wait for the API response, resolving the timeout without modifying the code. This is a configuration change in the Lambda function settings, not a code change.

Answer

Increase the reserved concurrency

Answer

Place the Lambda function in a VPC

Answer

Decrease the memory allocation of the Lambda function

Question 9

A company is deploying a microservices architecture on Amazon ECS. Each service needs to store secrets such as database passwords. Which service should be used to securely inject these secrets into containers?

Accepted Answer

AWS Secrets Manager. AWS Secrets Manager and AWS Systems Manager Parameter Store are both natively integrated with Amazon ECS for injecting sensitive data into containers as environment variables or log configuration options. To make AWS Secrets Manager the uniquely correct answer, the stem must specify a requirement that only Secrets Manager supports, such as automatic rotation of database credentials.

Answer

Amazon Elastic File System (EFS)

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Amazon S3

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AWS Systems Manager Parameter Store

Question 10

A developer is designing a serverless application that uses AWS Lambda and Amazon DynamoDB. The application needs to handle high traffic spikes without data loss. Which TWO actions should the developer take?

Accepted Answer

Enable DynamoDB Auto Scaling. DynamoDB Auto Scaling automatically adjusts the provisioned read and write capacity based on actual traffic patterns, preventing throttling during traffic spikes while maintaining cost efficiency. This ensures the application can handle high traffic without data loss by dynamically scaling the database's throughput capacity.

Answer

Use Provisioned IOPS for DynamoDB

Answer

Enable DynamoDB Streams

Answer

Increase the Lambda concurrency limit to the maximum

Question 11

A company is using AWS CodePipeline to automate its CI/CD pipeline. The pipeline has a source stage that pulls code from an Amazon S3 bucket. Which THREE steps should the developer take to ensure that only approved changes are deployed to production?

Accepted Answer

Use AWS CloudFormation change sets to review changes. AWS CloudFormation change sets allow you to preview how proposed changes to a stack will impact existing resources before you execute them. By reviewing the change set, you can verify that only approved modifications (e.g., infrastructure updates) are applied, providing a safety check before deployment to production. This step ensures that unapproved or unintended changes are caught early in the pipeline.

Answer

Configure cross-account access for the pipeline

Answer

Encrypt the S3 bucket with AWS KMS

Question 12

A developer needs to monitor the performance of an Amazon RDS for MySQL database. Which TWO metrics should the developer monitor to detect a potential CPU bottleneck?

Accepted Answer

DatabaseConnections. High CPUUtilization (Option C) directly indicates the CPU is under heavy load, which is the primary symptom of a CPU bottleneck. DatabaseConnections (Option B) is correct because an excessive number of concurrent connections can overwhelm the CPU as each connection requires context switching and query processing, leading to CPU saturation. Monitoring both metrics together helps distinguish between a CPU bottleneck caused by high query load versus one caused by connection overhead.

Answer

FreeStorageSpace

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NetworkThroughput

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ReadLatency

Question 13

Refer to the exhibit. An IAM policy is attached to an IAM user. The user tries to upload an object to s3://my-bucket/confidential/report.pdf. What is the outcome?

Accepted Answer

The upload fails because the Deny statement explicitly denies access to the confidential prefix.. The IAM policy includes an explicit Deny statement for s3:PutObject on the `confidential` prefix, which overrides any Allow statements. AWS IAM evaluates policies with explicit Denies taking precedence over Allows, so the upload to `s3://my-bucket/confidential/report.pdf` is blocked regardless of the Allow statement on the bucket.

Answer

The upload succeeds because the Allow statement grants s3:PutObject on the bucket.

Answer

The upload fails because there is no Allow statement for the confidential prefix.

Answer

The upload fails because the policy is malformed.

Question 14

Refer to the exhibit. A developer ran the AWS CLI command to invoke a Lambda function. The response indicates an error. What should the developer do to see the error details?

Accepted Answer

Read the output.txt file for the error message.. When invoking a Lambda function via the AWS CLI using `aws lambda invoke`, the command requires an output file parameter (e.g., `output.txt`). If the function execution fails, the CLI response payload containing the error message, error type, and stack trace is written directly to this output file. Reading the output file is the correct and most direct way to view these error details.

Answer

Decode the LogResult value from base64 to see the logs.

Answer

Check CloudWatch Logs for the function's log group.

Answer

Increase the Lambda function timeout to avoid the error.

Question 15

Refer to the exhibit. A developer created this CloudFormation template for an S3 bucket. What is the expected behavior?

Accepted Answer

Noncurrent versions of objects are deleted 30 days after they become noncurrent.. The CloudFormation template defines an S3 Lifecycle rule with `NoncurrentVersionExpiration` set to 30 `NoncurrentDays`. This rule specifically targets noncurrent versions of objects, meaning that after an object version becomes noncurrent (e.g., due to a PUT or DELETE of the current version), that noncurrent version will be permanently deleted 30 days later. The `Status: Enabled` ensures the rule is active, and versioning is enabled via the `VersioningConfiguration` property.

Answer

The bucket will have versioning disabled because the rule conflicts.

Answer

Current versions are transitioned to another storage class after 30 days.

Answer

Objects are automatically deleted after 30 days.