Amazon Web Services DVA-C02 Exam With Confidence Using Practice Dumps

CloudWatch for Log Analysis: CloudWatch is the best fit here because logs are already centralized. Here ' s the process:

Metric Filter: Create a metric filter on the CloudWatch Logs log group. Design a pattern to specifically identify application error messages.

Custom Metric: This filter generates a new custom CloudWatch metric (e.g., ApplicationErrors). This metric tracks the error count.

CloudWatch Alarm: Create an alarm on the ApplicationErrors metric. Configure the alarm with your desired threshold and a 5-minute evaluation period.

SNS Action: Set the alarm to trigger an SNS notification when it enters the alarm state.

To monitor end-to-end requests and debug issues across microservices, you need distributed tracing. Among AWS tools, AWS X-Ray is specifically built for this use case.

Step-by-Step Breakdown:

Step 1: Understand the Requirement

The developer needs:

End-to-end request tracing across microservices

Debugging capability for performance issues or failures

This points directly to a distributed tracing solution rather than just logs or metrics.

Step 2: Evaluate the Options

Option A: Amazon CloudWatch

CloudWatch is powerful for metrics, logs, and alerts.

But it does not provide distributed tracing or request path visualization between microservices.

So, it ' s not sufficient alone for the requirement.

Option B: AWS CloudTrail

CloudTrail tracks API calls made through the AWS Management Console, CLI, SDKs.

It is meant for auditing and governance, not microservices request tracing.

Not suitable for debugging microservices interactions.

Option C: AWS X-Ray SDK with X-Ray service map

Purpose-built for distributed tracing

Automatically collects data about requests as they travel through your microservices

You can instrument your code with the AWS X-Ray SDK in Java, Node.js, Python, Go, .NET, etc.

Visualizes requests using a service map, showing latency, errors, and time spent in downstream services.

How it works:

Instrument each microservice using the AWS X-Ray SDK.

Use the SDK to trace requests, propagate trace headers across services.

The X-Ray daemon collects and sends trace data to the X-Ray service.

You can view the service map, see bottlenecks, error rates, etc.

Option D: AWS Health

AWS Health provides information on AWS service outages or account-level events.

It does not monitor your application or microservices health or request flows.

Correct Choice: C is the only option that meets the developer ' s requirement to monitor end-to-end request paths and debug issues in a microservices architecture.

AWS Developer References:

AWS X-Ray Documentation:

Instrumenting your application:

Viewing the Service Map:

Tracing Microservices with AWS X-Ray:

When a Lambda function is configured to run inside a VPC, it receives ENIs in the selected subnets and uses those subnets’ routing to reach other networks. If the function is placed in private subnets (common when it needs to access an RDS database in private subnets), it typically does not have a direct route to the internet. As a result, outbound calls to public external APIs will fail unless the VPC provides a controlled egress path.

The standard AWS networking pattern for private-subnet internet access is a NAT gateway (or NAT instance) deployed in a public subnet , with a route from the private subnet(s) to the NAT gateway (0.0.0.0/0 → NAT). The NAT gateway then uses an internet gateway attached to the VPC to reach the public internet while keeping the Lambda function (and the RDS database) in private address space. This resolves the connectivity issue while maintaining the security posture of private subnets.

Option A is not the solution: Lambda automatically provisions ENIs for VPC-enabled functions; manually provisioning an ENI does not provide internet access. Option C (security group outbound rules) is necessary but not sufficient—security groups control allowed traffic, but without a proper route to the internet (via NAT), the packets still cannot reach external endpoints. Option D (gateway VPC endpoint) is for AWS services like S3 and DynamoDB (gateway endpoints), not for arbitrary public internet APIs, and “in a public subnet” is not how gateway endpoints are used; they are associated with route tables.

Therefore, the correct solution is B : add a NAT gateway in a public subnet and update private subnet route tables so the new Lambda function can reach external public APIs while still accessing the private RDS database.