Practice Free DVA-C02 Exam Online Questions
A developer needs to deploy an application running on AWS Fargate using Amazon ECS The application has environment variables that must be passed to a container for the application to initialize.
How should the environment variables be passed to the container?
- A . Define an array that includes the environment variables under the environment parameter within the service definition.
- B . Define an array that includes the environment variables under the environment parameter within the task definition.
- C . Define an array that includes the environment variables under the entryPoint parameter within the task definition.
- D . Define an array that includes the environment variables under the entryPoint parameter within the service definition.
B
Explanation:
This solution allows the environment variables to be passed to the container when it is launched by AWS Fargate using Amazon ECS. The task definition is a text file that describes one or more containers that form an application. It contains various parameters for configuring the containers, such as CPU and memory requirements, network mode, and environment variables. The environment parameter is an array of key-value pairs that specify environment variables to pass to a container. Defining an array that includes the environment variables under the entryPoint parameter within the task definition will not pass them to the container, but use them as command-line arguments for overriding the default entry point of a container. Defining an array that includes the environment variables under the environment or entryPoint parameter within the service definition will not pass them to the container, but cause an error because these parameters are not valid for a service definition.
Reference: [Task Definition Parameters], [Environment Variables]
A company has a web application that contains an Amazon API Gateway REST API. A developer has created an AWS CloudFormation template for the initial deployment of the application. The developer has deployed the application successfully as part of an AWS CodePipeline continuous integration and continuous delivery (CI/CD) process. All resources and methods are available through the deployed stage endpoint.
The CloudFormation template contains the following resource types:
• AWS::ApiGateway::RestApi
• AWS::ApiGateway::Resource
• AWS::ApiGateway::Method
• AWS:ApiGateway::Stage
• AWS::ApiGateway:;Deployment
The developer adds a new resource to the REST API with additional methods and redeploys the template. CloudFormation reports that the deployment is successful and that the stack is in the UPDATE_COMPLETE state. However, calls to all new methods are returning 404 (Not Found) errors.
What should the developer do to make the new methods available?
- A . Specify the disable-rollback option during the update-stack operation.
- B . Unset the Cloud Forma lion stack failure options.
- C . Add an AWS CodeBuild stage lo CodePipeline to run the aws apigateway create-deployment AWS CLI command.
- D . Add an action to CodePipeline to run the aws cloudfront create-invalidation AWS CLI command.
A company is using the AWS Serverless Application Model (AWS SAM) to develop a social media application. A developer needs a quick way to test AWS Lambda functions locally by using test event payloads. The developer needs the structure of these test event payloads to match the actual events that AWS services create.
- A . Create shareable test Lambda events. Use these test Lambda events for local testing.
- B . Store manually created test event payloads locally. Use the sam local invoke command with the file path to the payloads.
- C . Store manually created test event payloads in an Amazon S3 bucket. Use the sam local invoke command with the S3 path to the payloads.
- D . Use the sam local generate-event command to create test payloads for local testing.
D
Explanation:
Comprehensive Detailed Step by Step Explanation with All AWS Developer
Reference: The AWS Serverless Application Model (SAM) includes features for local testing and debugging of AWS Lambda functions. One of the most efficient ways to generate test payloads that match actual AWS event structures is by using the sam local generate-event command.
sam local generate-event: This command allows developers to create pre-configured test event payloads for various AWS services (e.g., S3, API Gateway, SNS). These generated events accurately reflect the format that the service would use in a live environment, reducing the manual work required to create these events from scratch.
Operational Overhead: This approach reduces overhead since the developer does not need to manually create or maintain test events. It ensures that the structure is correct and up-to-date with the latest AWS standards.
Alternatives:
Option A suggests using shareable test events, but manually creating or sharing these events introduces more overhead.
Option B and C both involve manually storing and maintaining test events, which adds unnecessary complexity compared to using sam local generate-event.
AWS SAM CLI documentation
A developer warns to add request validation to a production environment Amazon API Gateway API.
The developer needs to test the changes before the API is deployed to the production environment.
For the lest the developer will send test requests to the API through a testing tool.
Which solution will meet these requirements with the LEAST operational overhead?
- A . Export the existing API to an OpenAPI file. Create a new API Import the OpenAPI file Modify the new API to add request validation. Perform the tests Modify the existing API to add request validation. Deploy the existing API to production.
- B . Modify the existing API to add request validation. Deploy the updated API to a new API Gateway stage Perform the tests Deploy the updated API to the API Gateway production stage.
- C . Create a new API Add the necessary resources and methods including new request validation. Perform the tests Modify the existing API to add request validation. Deploy the existing API to production.
- D . Clone the exiting API Modify the new API lo add request validation. Perform the tests Modify the existing API to add request validation Deploy the existing API to production.
D
Explanation:
This solution allows the developer to test the changes without affecting the production environment. Cloning an API creates a copy of the API definition that can be modified independently. The developer can then add request validation to the new API and test it using a testing tool. After verifying that the changes work as expected, the developer can apply the same changes to the existing API and deploy it to production.
Reference: Clone an API, [Enable Request Validation for an API in API Gateway]
A developer wants the ability to roll back to a previous version of an AWS Lambda function in the event of errors caused by a new deployment.
How can the developer achieve this with MINIMAL impact on users?
- A . Change the application to use an alias that points to the current version. Deploy the new version of the code Update the alias to use the newly deployed version. If too many errors are encountered, point the alias back to the previous version.
- B . Change the application to use an alias that points to the current version. Deploy the new version of the code. Update the alias to direct 10% of users to the newly deployed version. If too many errors are encountered, send 100% of traffic to the previous version
- C . Do not make any changes to the application. Deploy the new version of the code. If too many errors are encountered, point the application back to the previous version using the version number in the Amazon Resource Name (ARN).
- D . Create three aliases: new, existing, and router. Point the existing alias to the current version. Have the router alias direct 100% of users to the existing alias. Update the application to use the router alias. Deploy the new version of the code. Point the new alias to this version. Update the router alias to direct 10% of users to the new alias. If too many errors are encountered, send 100% of traffic to the existing alias.
A company uses Amazon DynamoDB as a data store for its order management system. The company frontend application stores orders in a DynamoDB table. The DynamoDB table is configured to send change events to a DynamoDB stream. The company uses an AWS Lambda function to log and process the incoming orders based on data from the DynamoDB stream.
An operational review reveals that the order quantity of incoming orders is sometimes set to 0. A developer needs to create a dashboard that will show how many unique customers this problem affects each day.
What should the developer do to implement the dashboard?
- A . Grant the Lambda function’s execution role permissions to upload logs to Amazon CloudWatch Logs. Implement a CloudWatch Logs Insights query that selects the number of unique customers for orders with order quantity equal to 0 and groups the results in 1-day periods. Add the CloudWatch Logs Insights query to a CloudWatch dashboard.
- B . Use Amazon Athena to query AWS CtoudTrail API logs for API calls. Implement an Athena query that selects the number of unique customers for orders with order quantity equal to 0 and groups the results in 1-day periods. Add the Athena query to an Amazon CloudWatch dashboard.
- C . Configure the Lambda function to send events to Amazon EventBridge. Create an EventBridge rule that groups the number of unique customers for orders with order quantity equal to 0 in 1-day periods. Add a CloudWatch dashboard as the target of the rule.
- D . Turn on custom Amazon CloudWatch metrics for the DynamoDB stream of the DynamoOB table. Create a CloudWatch alarm that groups the number of unique customers for orders with order quantity equal to 0 in 1-day periods. Add the CloudWatch alarm to a CloudWatch dashboard.
A developer needs to store configuration variables for an application. The developer needs to set an expiration date and time for me configuration. The developer wants to receive notifications. Before the configuration expires.
Which solution will meet these requirements with the LEAST operational
overhead?
- A . Create a standard parameter in AWS Systems Manager Parameter Store Set Expiation and Expiration Notification policy types.
- B . Create a standard parameter in AWS Systems Manager Parameter Store Create an AWS Lambda function to expire the configuration and to send Amazon Simple Notification Service (Amazon SNS) notifications.
- C . Create an advanced parameter in AWS Systems Manager Parameter Store Set Expiration and Expiration Notification policy types.
- D . Create an advanced parameter in AWS Systems Manager Parameter Store Create an Amazon EC2 instance with a corn job to expire the configuration and to send notifications.
C
Explanation:
This solution will meet the requirements by creating an advanced parameter in AWS Systems Manager Parameter Store, which is a secure and scalable service for storing and managing configuration data and secrets. The advanced parameter allows setting expiration and expiration notification policy types, which enable specifying an expiration date and time for the configuration and receiving notifications before the configuration expires. The Lambda code will be refactored to load the Root CA Cert from the parameter store and modify the runtime trust store outside the Lambda function handler, which will improve performance and reduce latency by avoiding repeated calls to Parameter Store and trust store modifications for each invocation of the Lambda function.
Option A is not optimal because it will create a standard parameter in AWS Systems Manager Parameter Store, which does not support expiration and expiration notification policy types.
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 create a Docker container from Node.js base image to invoke Lambda functions, which will incur additional costs and overhead for creating and running Docker containers.
Reference: AWS Systems Manager Parameter Store, [Using SSL/TLS to Encrypt a Connection to a DB Instance]
A developer needs to troubleshoot an AWS Lambda function in a development environment. The Lambda function is configured in VPC mode and needs to connect to an existing Amazon RDS for SOL Server DB instance. The DB instance is deployed in a private subnet and accepts connections by using port 1433.
When the developer tests the function, the function reports an error when it tries to connect to the database.
Which combination of steps should the developer take to diagnose this issue? (Select TWO.)
- A . Check that the function’s security group has outbound access on port 1433 to the DB instance’s security group. Check that the DB instance’s security group has inbound access on port 1433 from the function’s security group.
- B . Check that the function’s security group has Inbound access on port 1433 from the DB Instance’s security group. Check that the DB instance’s security group has outbound access on port 1433 to the function’s security group.
- C . Check that the VPC is set up for a NAT gateway. Check that the DB instance has the public access option turned on.
- D . Check that the function’s execution role permissions include rds:DescribeDBInstances, rds: ModifyDB Instance, and rds:DescribeDBSecurityGroups for the DB instance.
- E . Check that the function’s execution rote permissions include ec2: CreateNetworklnterface. ec2: DescribeNetworklnterfaces. and ec2: DeleteNetworklnterface.
A developer is preparing to begin development of a new version of an application. The previous version of the application is deployed in a production environment. The developer needs to deploy fixes and updates to the current version during the development of the new version of the application. The code for the new version of the application is stored in AWS CodeCommit.
Which solution will meet these requirements?
- A . From the main branch, create a feature branch for production bug fixes. Create a second feature branch from the main branch for development of the new version.
- B . Create a Git tag of the code that is currently deployed in production. Create a Git tag for the development of the new version. Push the two tags to the CodeCommit repository.
- C . From the main branch, create a branch of the code that is currently deployed in production. Apply an IAM policy that ensures no other other users can push or merge to the branch.
- D . Create a new CodeCommit repository for development of the new version of the application.
Create a Git tag for the development of the new version.
A
Explanation:
A feature branch is a branch that is created from the main branch to work on a specific feature or task1. Feature branches allow developers to isolate their work from the main branch and avoid conflicts with other changes1. Feature branches can be merged back to the main branch when the feature or task is completed and tested1.
In this scenario, the developer needs to maintain two parallel streams of work: one for fixing and updating the current version of the application that is deployed in production, and another for developing the new version of the application. The developer can use feature branches to achieve this goal.
The developer can create a feature branch from the main branch for production bug fixes. This branch will contain the code that is currently deployed in production, and any fixes or updates that need to be applied to it. The developer can push this branch to the CodeCommit repository and use it to deploy changes to the production environment.
The developer can also create a second feature branch from the main branch for development of the new version of the application. This branch will contain the code that is under development for the new version, and any changes or enhancements that are part of it. The developer can push this branch to the CodeCommit repository and use it to test and deploy the new version of the application in a separate environment.
By using feature branches, the developer can keep the main branch stable and clean, and avoid mixing code from different versions of the application. The developer can also easily switch between branches and merge them when needed.
An application that is deployed to Amazon EC2 is using Amazon DynamoDB. The app cation calls the DynamoDB REST API Periodically the application receives a ProvisionedThroughputExceededException error when the application writes to a DynamoDB table.
Which solutions will mitigate this error MOST cost-effectively^ (Select TWO)
- A . Modify the application code to perform exponential back off when the error is received.
- B . Modify the application to use the AWS SDKs for DynamoDB.
- C . Increase the read and write throughput of the DynamoDB table.
- D . Create a DynamoDB Accelerator (DAX) cluster for the DynamoDB table.
- E . Create a second DynamoDB table Distribute the reads and writes between the two tables.
A,B
Explanation:
These solutions will mitigate the error most cost-effectively because they do not require increasing the provisioned throughput of the DynamoDB table or creating additional resources. Exponential backoff is a retry strategy that increases the waiting time between retries to reduce the number of requests sent to DynamoDB. The AWS SDKs for DynamoDB implement exponential backoff by default and also provide other features such as automatic pagination and encryption. Increasing the read and write throughput of the DynamoDB table, creating a DynamoDB Accelerator (DAX) cluster, or creating a second DynamoDB table will incur additional costs and complexity.
Reference: [Error Retries and Exponential Backoff in AWS], [Using the AWS SDKs with DynamoDB]