DOP-C02 Monitoring and Logging — Timed 15 Questions

Question 1

A company wants to monitor the number of messages in an Amazon SQS queue and send an alert if the queue depth exceeds 1000 for more than 5 minutes. Which AWS service should be used to create the alarm?

15 minute time limit — choose an answer to begin.

Accepted Answer

Amazon CloudWatch Alarms. Amazon CloudWatch Alarms is the correct service because it can monitor SQS queue metrics (such as ApproximateNumberOfMessagesVisible) and trigger an alarm when the metric exceeds a threshold (e.g., 1000) for a specified evaluation period (e.g., 5 minutes). CloudWatch Alarms directly integrate with SQS via the AWS/SQS namespace and support actions like sending notifications through Amazon SNS.

Answer

Amazon EventBridge

Answer

AWS X-Ray

Answer

Amazon CloudWatch Logs

Question 2

A company is using Amazon CloudWatch Synthetics canaries to monitor its web application endpoints. The canaries are deployed in multiple AWS regions. The team wants to aggregate the canary results into a single dashboard in the US East (N. Virginia) region. What is the MOST efficient way to achieve this?

Accepted Answer

Create a cross-region CloudWatch dashboard and add metrics from each region using metric math.. CloudWatch cross-region dashboards allow you to aggregate metrics from multiple regions into a single dashboard without data movement. By using metric math, you can reference metric IDs from different regions directly in the dashboard widget, enabling real-time aggregation of Synthetics canary success/failure rates and latency metrics from all regions into a unified view in US East (N. Virginia). This approach avoids unnecessary data replication, reduces latency, and minimizes operational overhead.

Answer

Replicate the canaries to US East (N. Virginia) and run them from there.

Answer

Set up a Lambda function in each region to push canary results to a central S3 bucket, then create a dashboard from S3.

Answer

Create a CloudWatch Logs Insights query across all regions and visualize results.

Question 3

A DevOps team is troubleshooting a slow application. They enabled AWS X-Ray tracing and see that one of the downstream services has a high average response time. However, the traces show that the service itself is fast; the delay is in the network call from the upstream service. Which X-Ray feature should the team use to identify the root cause?

Accepted Answer

Examine the trace map to see the connection between services.. The trace map in AWS X-Ray provides a visual representation of the service graph, showing the connections and latency between services. Since the delay is in the network call from the upstream service to the downstream service, the trace map can highlight the specific edge where the high latency occurs, allowing the team to pinpoint whether the issue is due to network congestion, DNS resolution, or a slow HTTP connection. This is the most direct way to identify the root cause of the inter-service communication delay.

Answer

Add annotations to the traces for better filtering.

Answer

View the raw segments of the upstream service.

Answer

Adjust the sampling rules to capture more traces.

Question 4

A company needs to monitor the CPU utilization of its Amazon RDS for PostgreSQL instance. The metric should be available in Amazon CloudWatch with a granularity of 1 minute. Which action should the team take?

Accepted Answer

No additional configuration is needed; RDS automatically sends metrics to CloudWatch.. Amazon RDS for PostgreSQL automatically publishes metrics, including CPU utilization, to CloudWatch with a default granularity of 1 minute for standard instances. No additional configuration is required to enable this basic monitoring. The metrics are collected by the RDS hypervisor layer and sent to CloudWatch without needing an agent or extra setup.

Answer

Install the CloudWatch agent on the RDS instance.

Answer

Enable Enhanced Monitoring for the RDS instance.

Answer

Enable Performance Insights for the RDS instance.

Question 5

A company runs a containerized application on Amazon ECS Fargate. The DevOps team wants to collect custom application metrics (e.g., request count, error rate) and send them to Amazon CloudWatch. The team wants to minimize changes to the application code. Which solution should be used?

Accepted Answer

Run the CloudWatch agent as a sidecar container in the ECS task definition, configured to collect StatsD metrics from the application container.. The CloudWatch agent can run as a sidecar container in the same ECS task definition and listen for StatsD metrics (over UDP port 8125) from the application container. This approach requires zero changes to the application code—the application simply emits StatsD-formatted metrics, and the CloudWatch agent forwards them to CloudWatch via the PutMetricData API. It minimizes operational overhead while enabling custom metric collection from containerized workloads on Fargate.

Answer

Have the application call the CloudWatch PutMetricData API directly.

Answer

Use the ECS agent's built-in metric collection feature.

Answer

Modify the application to send logs using the embedded metric format.

Question 6

A DevOps engineer is designing a monitoring solution for a serverless application using AWS Lambda, Amazon API Gateway, and Amazon DynamoDB. The team needs to monitor for errors and latency. Which TWO actions should the engineer take to implement comprehensive monitoring? (Choose TWO.)

Accepted Answer

Enable AWS X-Ray tracing on API Gateway and Lambda.. AWS X-Ray provides end-to-end tracing for requests as they travel through API Gateway, Lambda, and DynamoDB, enabling the team to identify latency bottlenecks and errors across the entire serverless application. This is essential for comprehensive monitoring of distributed applications, as it captures detailed timing and error data for each component.

Answer

Enable DynamoDB Accelerator (DAX) to reduce latency.

Answer

Enable detailed billing metrics for cost analysis.

Answer

Configure CloudWatch Logs for DynamoDB.

Question 7

A company uses Amazon CloudWatch Logs to store logs from multiple applications. The security team requires that logs are encrypted at rest using a customer-managed KMS key. Additionally, logs must be retained for 7 years for compliance. Which THREE steps should the DevOps engineer take to meet these requirements? (Choose THREE.)

Accepted Answer

Set the log group retention policy to 2557 days (7 years).. CloudWatch Logs log group retention policies accept values in days, and 7 years equals 2557 days (7 × 365.25, accounting for leap years). Setting this retention policy ensures logs are automatically deleted after the compliance period, meeting the 7-year retention requirement without manual intervention.

Answer

Modify the existing log group to use the KMS key by updating the log group settings.

Answer

Set the log group retention policy to 'Never expire' and use lifecycle policies to transition logs to Amazon S3 Glacier after 30 days.

Question 8

A DevOps engineer is monitoring an Amazon EC2 Auto Scaling group. The engineer wants to receive notifications when instances are launched or terminated. Which TWO AWS services can be used together to achieve this? (Choose TWO.)

Accepted Answer

AWS CloudTrail. Amazon CloudTrail captures API calls made to the EC2 Auto Scaling service, including RunInstances and TerminateInstances events. CloudTrail can be configured to deliver these events directly to an Amazon SNS topic, enabling real-time notifications when instances are launched or terminated. This makes CloudTrail and SNS a valid combination. Amazon CloudWatch Alarms (option C) are not required for this purpose, as CloudTrail's direct integration with SNS provides the notification capability without additional services.

Answer

AWS X-Ray

Answer

AWS Config

Answer

Amazon CloudWatch Alarms

Question 9

A company runs a critical application on Amazon ECS with Fargate. The application experiences intermittent slow responses. The DevOps team enabled Container Insights and CloudWatch ServiceLens. However, traces from the application do not appear in ServiceLens. The application uses the AWS X-Ray SDK for tracing. What is the MOST likely cause?

Accepted Answer

The X-Ray daemon is not running in the task definition.. The X-Ray daemon is required to act as a local intermediary that receives trace segments from the X-Ray SDK and forwards them to the AWS X-Ray API. In Amazon ECS with Fargate, the daemon must be explicitly included as a sidecar container in the task definition. Without it, the SDK cannot send traces, which explains why traces are missing from ServiceLens despite the SDK being integrated.

Answer

The X-Ray SDK cannot send traces to AWS X-Ray from Fargate tasks.

Answer

ServiceLens does not support Amazon ECS with Fargate launch type.

Answer

The application is not sending metrics to CloudWatch Container Insights.

Question 10

A DevOps team has set up centralized logging for multiple AWS accounts using Amazon OpenSearch Service. The team uses CloudWatch cross-account observability to collect logs from various accounts into a monitoring account. Recently, logs from one source account stopped appearing in the monitoring account's OpenSearch dashboard. Other source accounts continue to send logs successfully. Which step should the team take to troubleshoot this issue?

Accepted Answer

Check the source account's CloudWatch Logs subscription filter for the OpenSearch destination.. The most likely cause of logs from a single source account failing to appear is a misconfigured or broken CloudWatch Logs subscription filter. This filter is responsible for forwarding log events from the source account to the OpenSearch destination in the monitoring account. If the filter is missing, misconfigured, or has been accidentally deleted, logs will not be sent, while other accounts continue to work normally.

Answer

Verify that the monitoring account's CloudWatch cross-account observability is enabled.

Answer

Review the source account's CloudWatch Logs retention policy to confirm logs are not expired.

Answer

Ensure the IAM role in the source account has the correct trust policy for the monitoring account.

Question 11

A company uses AWS CloudFormation to deploy infrastructure. The DevOps team wants to receive notifications when a stack fails to create or update. What is the MOST efficient way to achieve this?

Accepted Answer

Configure an SNS topic in the stack's notification options.. AWS CloudFormation natively supports specifying Amazon SNS topic ARNs in the stack's notification options. When a stack operation (create, update, or delete) fails, CloudFormation automatically publishes a notification to the configured SNS topic without requiring any custom code, additional resources, or external event processing. This is the most efficient approach as it leverages built-in functionality with zero maintenance overhead.

Answer

Create a custom resource in the stack that publishes to Amazon SNS.

Answer

Create a CloudWatch alarm on the StackStatus metric.

Answer

Use Amazon EventBridge to capture CloudFormation events and publish to SNS.

Question 12

A DevOps engineer is troubleshooting a production AWS Lambda function that occasionally times out. The function has a timeout of 30 seconds and uses a synchronous invocation. The engineer wants to capture invocation logs to identify the cause. Which approach will provide the MOST detailed diagnostic information?

Accepted Answer

Enable AWS X-Ray tracing on the Lambda function.. AWS X-Ray provides end-to-end tracing for Lambda functions, capturing detailed timing information for each invocation, including subsegments for downstream calls, function initialization, and execution phases. This allows the engineer to pinpoint exactly where time is being spent, which is essential for diagnosing intermittent timeouts in synchronous invocations.

Answer

Enable AWS CloudTrail data events for Lambda.

Answer

Create a CloudWatch dashboard with function duration metrics.

Answer

Add more logging statements to the function code and check CloudWatch Logs.

Question 13

A company runs a web application on Amazon EC2 instances behind an Application Load Balancer. The DevOps team has enabled detailed CloudWatch metrics for the ALB and is using CloudWatch Logs for the EC2 instances. Recently, users report intermittent 503 errors. The team notices that the ALB's 'RequestCount' metric shows a sudden drop during error periods, while the 'ActiveConnectionCount' remains steady. Which TWO steps should the team take to diagnose the issue? (Choose two.)

Accepted Answer

Enable and analyze the ALB access logs to see the HTTP response codes and target processing time.. ALB access logs contain detailed per-request data, including HTTP response codes (e.g., 503) and target processing time. Analyzing these logs will reveal whether the 503 errors are coming from the ALB itself (e.g., due to request queue overflow) or from the targets, and whether the sudden drop in RequestCount is due to clients aborting or the ALB throttling requests.

Answer

Check the Amazon Route 53 health checks for the ALB DNS name.

Answer

Review the EC2 instances' CloudWatch metrics for CPU utilization and network traffic.

Answer

Inspect AWS CloudTrail logs for the ALB to see if there are any configuration changes.

Question 14

A DevOps team is designing a monitoring strategy for a microservices application deployed on Amazon EKS. The application emits custom metrics, and the team needs to collect them with minimal latency and at high resolution. The team also needs to retain logs for 90 days for compliance. Which THREE steps should the team take to meet these requirements? (Choose three.)

Accepted Answer

Use Fluent Bit daemonset to send application logs to CloudWatch Logs.. Fluent Bit is a lightweight, high-performance log processor that can be deployed as a DaemonSet on Amazon EKS to collect application logs with minimal latency. It sends logs directly to CloudWatch Logs, which supports a retention policy of up to 10 years, easily meeting the 90-day compliance requirement. Fluent Bit's low resource footprint and efficient data pipeline ensure high-resolution log collection without impacting application performance.

Answer

Stream logs to Amazon Kinesis Data Firehose for transformation before landing in CloudWatch Logs.

Answer

Enable CloudWatch Container Insights for the EKS cluster.

Question 15

A company is using AWS CloudTrail to log API activity in their AWS account. They want to ensure that any modification to CloudTrail configuration itself is logged and that the logs are immutable. Which combination of actions should they take? (Choose TWO.)

Accepted Answer

Enable S3 Object Lock on the destination S3 bucket in governance mode.. Enabling S3 Object Lock in governance mode on the destination S3 bucket prevents any user, including the root user, from overwriting or deleting CloudTrail log objects during the retention period, ensuring immutability. Option B is correct because enabling log file validation creates a digest file that uses SHA-256 hashing to verify that log files have not been modified, deleted, or tampered with after delivery, providing integrity assurance.

Answer

Disable log file validation to reduce overhead.

Answer

Store CloudTrail logs in a CloudWatch Logs log group with a retention policy.

Answer

Enable CloudTrail Insights to detect configuration changes.