Free Practice Questions for Amazon Web Services DVA-C02 Exam

This solution will meet the requirements by creating a Lambda function execution role, which is an IAM role that grants permissions to a Lambda function to access AWS resources such as Amazon S3 objects. The developer can attach a policy to the role that grants access to specific objects in the S3 bucket that are required by the application, following the principle of least privilege. Option A is not optimal because it will hardcode the credentials that are required to access S3 objects in the application code, which is insecure and difficult to maintain. Option B is not optimal because it will create a secret access key and access key ID with permission to access the S3 bucket, which will introduce additional security risks and complexity for storing and managing credentials. Option D is not optimal because it will store the secret access key and access key ID as environment variables in Lambda, which is also insecure and difficult to maintain.

Requirement Summary:

Developer usesAWS IAM Identity Center (SSO)withAWS CLI / SDKs

Initially working fine

Now receiving AccessDenied errors

No changes to config or scripts

Key Understanding:

IAM Identity Center credentials aretemporary and time-limited. When you use SSO-based access via the AWS CLI (aws sso login), it obtainstemporary credentialsstored in the local cache.

By default,these expire in 1 hour(can be extended).

Evaluate Options:

A. Permissions to CLI binary changed

❌Unlikely – this would produce execution errors, not AccessDenied from AWS API

B. Permission set lacks required permissions

❌Then the error would have occurred from the beginning, not after time

✅C. IAM Identity Center credentials expired

✅Most likely– user hasn't refreshed credentials using aws sso login again

After expiration, API calls fail with AccessDenied

D. Developer is calling the wrong AWS account

❌Would likely show different types of errors (AccountNotFound, etc.)

SSO and AWS CLI:https://docs.aws.amazon.com/cli/latest/userguide/cli-configure-sso.html

Troubleshooting SSO CLI:https://docs.aws.amazon.com/cli/latest/userguide/sso-configure-profile-token.html

API Gateway Mocking: This feature is built for decoupling development dependencies. Here's the process:

Create resources and methods in your API Gateway.

Set the integration type to 'MOCK'.

Define Integration Responses, mapping HTTP status codes to desired mocked responses (JSON, etc.).

Deployment and Use:

Create a deployment stage for the API.

Frontend teams can call this API and get the mocked responses without a real backend.

API Gateway’scanary deploymentsallow gradual traffic shifting to a new version of a function, minimizing disruption while testing.

Why Option A is Correct:

Gradual Rollout: Reduces risk by incrementally increasing traffic.

Rollback Support: Canary deployments make it easy to revert to the previous version.

Why Not Other Options:

Option B: Redeploying the stage disrupts all users.

Option C & D: Managing new stages and weighted routing introduces unnecessary complexity.

Requirement Summary:

Orders are being processedmore than once

Need to preventduplicate processing

Looking forleast implementation effort

Key Concept:

Lambda + Event-driven patternscan occasionally result induplicate invocations(at-least-once delivery model)

You needidempotency(i.e., prevent repeated processing of same event)

Evaluate Options:

✅A. Use DynamoDB for de-duplication

✅Simple and widely used approach

Store a unique orderId as the primary key

Before processing,check if order exists

If yes → skip

If no → process and store the ID

✅Minimal code changes required

B. ECS + Step Functions

❌Overkill for basic de-duplication

Adds significant complexity

C. Retry logic with fixed delay

❌Doesn't prevent duplication —makes it worse

Retrying might trigger thesame message again

D. Athena to identify duplicates

❌Reactive solution, not preventative

Not suitable for real-time event de-duplication

Lambda idempotency:https://docs.aws.amazon.com/lambda/latest/dg/invocation-retries.html

Using DynamoDB for idempotent design:https://aws.amazon.com/blogs/compute/how-to-design-idempotent-APIs-on-aws/

The solution that will meet the requirements most efficiently is to create a Lambda environment variable to store the table name. Use the standard method for the programming language to retrieve the variable. This way, the developer can avoid hard-coding the table name in the Lambda function code and easily change the table name by updating the environment variable. The other options either involve storing the table name in a file, which is less efficient and secure than using an environment variable, or creating a global variable, which is not recommended as it can cause concurrency issues.

Amazon ElastiCache for Memcached is a fully managed, multithreaded, and scalable in-memory key-value store that can be used to cache frequently accessed data andimprove application performance1. By using Amazon ElastiCache for Memcached, the developer can reduce the load on the main database and handle high traffic surges more efficiently.

To use Amazon ElastiCache for Memcached, the developer needs to create a cache cluster with one or more nodes, and configure the application to store and retrieve data from the cache cluster2. The developer can use any of the supported Memcached clients to interact with the cache cluster3. The developer can also use Auto Discovery to dynamically discover and connect to all cache nodes in a cluster4.

Amazon ElastiCache for Memcached is compatible with the Memcached protocol, which means that the developer can use existing tools and libraries that work with Memcached1. Amazon ElastiCache for Memcached also supports data partitioning, which allows the developer to distribute data among multiple nodes and scale out the cache cluster as needed.

Using Amazon ElastiCache for Memcached is a simple and effective solution that meets the requirements with the least complexity. The developer does not need to change the database schema, migrate data to a different service, or use a different caching model. The developer can leverage the existing Memcached ecosystem and easily integrate it with the application.