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

AWS Elastic Beanstalk supports several deployment policies, and in this case, the requirement is to forward a specific percentage of traffic to the new version without causing downtime. TheTraffic-splittingdeployment policy is the most appropriate choice.

Traffic-splitting Deployment: This deployment method allows you to gradually shift a specified percentage of incoming traffic from the old environment version to the new one. During the evaluation period, if any issues are detected, the traffic can be redirected back to the old version.

No Downtime: This method ensures no downtime since both versions of the application run concurrently, and traffic is split between them.

Alternatives:

Rolling deployments (Option A): These gradually replace instances but may result in partial downtime if some instances fail during deployment.

In-place deployments (Option C): In-place deployments replace instances without creating new ones, which can lead to downtime.

Immutable deployments (Option D): While this ensures no downtime by creating entirely new instances, it doesn't provide traffic splitting during the evaluation phase.

https://docs.aws.amazon.com/IAM/latest/UserGuide/reference_policies_examples_lambda-access-dynamodb.html

Option B:Thetarget group portin the ALB must match the port specified in the ECS task definition. If there is a mismatch, the ALB health check will fail since it cannot correctly route traffic to the container.

Option E:The ALB listener must have a default action that forwards requests to the correct target group associated with the ECS service. If this configuration is missing, the health check will fail as no traffic is routed to the service.

Option Ais irrelevant to resolving health check issues since capacity providers relate to provisioning compute capacity.

Option C(hosted zone) is not directly related to ALB health checks.

Option D(redirecting traffic) is not related to ECS health check configurations.

Why Option A is Correct:Creating a CloudWatch metric filter with "ERROR" as the search term ensures that occurrences of the word "ERROR" in logs are counted. An alarm can then be set to notify the SNS topic when the count exceeds 1. This is the standard approach to monitor specific patterns in CloudWatch Logs.

Why Other Options are Incorrect:

Option B:CloudWatch Logs Insights is used for querying logs manually and does not integrate directly with alarms for automated notifications.

Option C:SNS subscription filters are not a feature for filtering log patterns in CloudWatch Logs.

Option D:CloudWatch alarms do not directly include log filter patterns; a metric filter is needed to create the metric first.

AWS Documentation References:

Creating CloudWatch Metric Filters

Amazon ElastiCache is a service that offers fully managed in-memory data stores that are compatible with Redis or Memcached. The developer can create an ElastiCache for Redis instance and enable encryption of data in transit and at rest. This will ensure that the PHI is encrypted at all times. The developer can store frequently accessed data in the cache and use Redis features such as sorting and ranking to enhance the performance of the application.

IAM instance profiles are containers for IAM roles that can be associated with EC2 instances. An IAM role is a set of permissions that grant access to AWS resources. An IAM role can be used to allow an EC2 instance to access an S3 bucket by including the appropriate permissions in the role’s policy. The S3:ListBucket permission allows listing the objects in an S3 bucket. By updating the IAM instance profile with this permission, the application on the EC2 instance can retrieve the objects from the S3 bucket and display them to the user. Reference: Using an IAM role to grant permissions to applications running on Amazon EC2 instances

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/