Pass the Amazon Web Services AWS Certified Associate DVA-C02 Questions and answers with CertsForce

Why Option A is Correct:DynamoDB supports incremental exports to Amazon S3 natively, making data analytics-ready with minimal operational overhead.

Why Other Options are Incorrect:

Option B: DynamoDB Streams require additional processing logic to write to S3, increasing complexity.

Option C & D: Using EMR for data movement adds unnecessary operational overhead compared to native exports.

AWS Documentation References:

DynamoDB Exports to S3

The IAM policy shown in the image is a resource-based policy that grants or denies access to an S3 bucket based on certain conditions. The first statement allows access to any S3 action on any object in the “DOC-EXAMPLE-BUCKET” bucket when the request is made over HTTPS (the value of aws:SecureTransport is true). The second statement denies access to the s3:GetObject and s3:PutObject actions on any object in the “DOC-EXAMPLE-BUCKET/secrets” prefix when the request is made over HTTP (the value of aws:SecureTransport is false). Therefore, the policy allows access on all objects in the “DOC-EXAMPLE-BUCKET” bucket except on objects that start with “secrets”. Reference: Using IAM policies for Amazon S3

Principle of Least Privilege: Granting specific permissions through an IAM role is more secure than directly attaching policies to a function or using root user credentials.

IAM Roles for Lambda: Designed to provide temporary credentials to Lambda functions, enhancing security.

Reusability: The existing IAM policy ensures the correct S3 and DynamoDB access is granted.

To securely grant temporary access to a specific S3 object, the best option is to use an Amazon S3 presigned URL . A presigned URL is created by an IAM principal (user or role) that already has permission to access the object. The URL includes a signature and an expiration time , allowing anyone who has the URL to perform the specified operation (typically GET to download, or PUT to upload) until the URL expires . This meets the requirement for temporary access without changing the bucket to be publicly accessible.

Presigned URLs are especially useful when the developer needs to share access with people who do not have AWS credentials or are not part of the same AWS account. The developer can set an expiration that matches the business need (minutes to hours, etc.). After expiration, the URL no longer works, which reduces security exposure compared with long-lived access keys or permanently permissive bucket policies.

Option C (bucket policy with time restriction) can enforce time-based access, but it is not a practical way to securely share with a “specific group of people” unless those people authenticate with identifiable principals (IAM roles/users, federated identities) and you scope the policy to those principals. Simply providing the bucket S3 URL would not grant access unless the recipients also have valid permissions. Option D (static website hosting) is generally for public web content and does not inherently provide secure, temporary, per-object access control. Option A is unrelated to access sharing; object retention and restore operations are for retention/compliance and archival retrieval, not temporary permission grants.

Therefore, generating and sharing a presigned URL (B) is the standard, secure mechanism for time-limited access to S3 objects.

The goal is minimal downtime during deployment and fast rollback if problems occur. In Elastic Beanstalk, the approach that best satisfies both is a blue/green deployment.

With blue/green, the developer deploys the new application version to a separate environment (green) while the current production environment (blue) continues serving traffic. Once validation is complete (health checks, smoke tests), the developer performs a controlled CNAME swap (or routing switch) so traffic shifts from blue to green with near-zero downtime. This reduces risk because the existing environment remains intact and can immediately resume traffic if issues are detected.

Rollback time is also minimized because reverting is simply switching traffic back to the original environment (swap back), rather than rolling back changes across the same environment.

Why the other options are weaker:

All-at-once (C) introduces the highest downtime and risk because it replaces all instances at once, potentially taking the application fully offline and making rollback slower.

Rolling (A) reduces downtime compared to all-at-once, but instances are still updated in-place; if issues appear mid-deployment, rollback is more complex and slower than swapping environments.

Rolling with additional batches (B) can further reduce capacity impact by adding extra instances during deployment, but rollback still involves reversing updates in the same environment and is typically slower than blue/green.

Therefore, deploying to a new environment and using blue/green provides the least downtime and the fastest rollback.

Amazon Simple Notification Service (Amazon SNS) is a fully managed messaging service that enables pub/sub communication between distributed systems. The developer can create an SNS topic and configure the Lambda function to publish messages with specific attributes to the topic. The developer can subscribe each partner to the SNS topic and apply the appropriate filter policy to the topic subscriptions. This way, each partner will receive updates for only their own orders based on the message attributes. This solution will meet the requirements in the most scalable way and allow adding new partners in the future with minimal code changes.

DynamoDB already supports encryption at rest by default (with AWS owned keys or AWS managed/customer managed KMS keys). However, the requirement here is stronger and explicit: patient data must be encrypted before it is stored in DynamoDB, meaning the encryption must occur client-side / application-side so that the data remains encrypted as it traverses the stack and is still encrypted when written to the table. This is often required for highly sensitive PII/PHI where administrators or downstream systems should not see plaintext.

Option A meets this requirement by encrypting the payload inside the Lambda function before making the PutItem call to DynamoDB, using KMS-backed envelope encryption via the AWS Encryption SDK (the option names it “Database Encryption SDK,” but the intent is client-side encryption). The encrypted fields remain ciphertext in transit to DynamoDB and at rest inside DynamoDB, satisfying both “in transit” and “at rest” with encryption happening prior to storage.

Option B only ensures DynamoDB encryption at rest at the service level, but the data would still be plaintext in the item attributes as seen by the application and anyone with DynamoDB read permissions (even though stored encrypted on disk). It does not guarantee “encrypted before stored.”

Option C encrypting after the write via streams is too late: plaintext would already be stored (and potentially accessed) before post-processing.

Option D adds unnecessary workflow complexity. Encrypting in a queue still requires encryption before DynamoDB, but it does not inherently simplify compared to encrypting directly in the Lambda that writes to DynamoDB.

Therefore, client-side encryption in Lambda using KMS-backed encryption is the correct solution.

Why Option D is Correct:When using a container-based AWS Lambda function, you are responsible for updating the base image for runtime patches. Rebuilding the container with the latest Node.js patch version ensures the function is updated with the required security patches. Publishing a new version of the Lambda function makes the updated image available for use.

Why Other Options are Incorrect:

Option A: The runtime update mode applies to functions using AWS-managed runtimes, not container-based runtimes.

Option B: Redeploying the same version of the Lambda function does not apply the security patch.

Option C: Rebuilding with the AWS OS base image does not guarantee that the latest Node.js patch version is included.

AWS Documentation References:

Lambda Function Container Images

Node.js Updates in AWS Lambda

https://docs.aws.amazon.com/step-functions/latest/dg/welcome.html

Comprehensive and Detailed Explanation (250–300 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.

Why Option B is Correct:Setting the visibility timeout ensures that once a message is being processed, it is temporarily hidden from other consumers. The Lambda function must delete processed messages to avoid re-processing when the visibility timeout expires.

Why Other Options are Incorrect:

Option A: Message retention affects how long messages stay in the queue, not how they are processed.

Option C: Receive message wait time optimizes long polling but does not prevent re-processing.

Option D: Delivery delay introduces latency for new messages and does not address message re-processing.

AWS Documentation References:

Using SQS Visibility Timeout

The solution that will meet the requirements is to add a global secondary index (GSI) to the DynamoDB table with customer_type as the partition key and email_address as the sort key. Perform a query operation on the GSI by using the begins_with key condition expression with the email_address property. This way, the developer can search for partial matches of the email_address property of a particular customer type without recreating the DynamoDB table. The other options either involve using a local secondary index (LSI), which requires recreating the table, or using a different partition key, which does not allow filtering by customer_type.

SQS Delivery Behavior: Standard SQS queues guarantee at-least-once delivery, meaning messages may be processed more than once. This can lead to duplicate emails in this scenario.

Visibility Timeout: If the visibility timeout on the SQS queue is too short, a message might become visible for another consumer before the first Lambda function finishes processing it. This can also lead to duplicates.