DOP-C02 Monitoring and Logging Practice Test 8 — 15 Questions

Question 1

A company uses Amazon CloudWatch Logs to store application logs. A DevOps engineer needs to create a real-time dashboard that displays the count of ERROR-level log entries across all instances. Which approach is the MOST efficient and cost-effective?

Accepted Answer

Use CloudWatch Logs Insights to run a query that counts ERROR entries across all log groups and add the query to a CloudWatch dashboard. Option C is correct because CloudWatch Logs Insights allows you to query logs across log groups in real-time and create dashboards. Option A is wrong because subscribing to a Kinesis stream adds complexity and cost. Option B is wrong because creating a custom metric filter for each log group is inefficient. Option D is wrong because exporting logs to S3 and using Athena is near real-time, not real-time.

Answer

Create a CloudWatch Logs metric filter for each log group to count ERROR entries, and then create a CloudWatch dashboard

Answer

Export logs to Amazon S3 and use Amazon Athena to query and visualize in Amazon QuickSight

Answer

Create a Kinesis Data Firehose delivery stream to stream logs to Amazon OpenSearch Service and build a dashboard in OpenSearch Dashboards

Question 2

A company runs a fleet of EC2 instances behind an Auto Scaling group. The DevOps team wants to detect and respond to memory leaks in their application. They have configured CloudWatch agent to collect memory metrics. However, the metric shows unpredictable spikes. The team needs to correlate these spikes with application logs to identify the root cause. Which solution provides the BEST correlation?

Accepted Answer

Use CloudWatch Logs Insights to query application logs for error patterns around the time of memory spikes. Option C is correct because CloudWatch Logs Insights allows you to query application logs directly in CloudWatch Logs using a purpose-built query language. By filtering logs around the timestamps of memory spikes, you can correlate specific error patterns or log entries with the metric data, enabling root cause analysis without moving data or adding complexity.

Answer

Export the memory metric and application logs to Amazon S3 and use Amazon Athena to join them

Answer

Enable AWS X-Ray on the application to trace requests and identify memory-heavy requests

Answer

Use Amazon EventBridge to capture EC2 instance state changes and correlate with memory spikes

Question 3

A DevOps engineer needs to monitor the number of messages in an Amazon SQS queue and trigger an Auto Scaling policy to add more EC2 instances when the queue depth exceeds a threshold. Which CloudWatch metric should the alarm use?

Accepted Answer

ApproximateNumberOfMessagesVisible. Option A is correct because ApproximateNumberOfMessagesVisible indicates the number of messages available for retrieval. Option B is wrong because NumberOfMessagesSent is a count of sent messages. Option C is wrong because ApproximateNumberOfMessagesNotVisible is for messages in flight. Option D is wrong because SentMessageSize is the size of messages.

Answer

NumberOfMessagesSent

Answer

ApproximateNumberOfMessagesNotVisible

Answer

SentMessageSize

Question 4

A DevOps engineer executes the above CloudWatch Logs Insights query. What will the output contain?

Accepted Answer

The count of ERROR messages per 5-minute interval for the most recent 20 intervals. Option C is correct because the query filters for 'ERROR' messages, counts them in 5-minute bins, and returns the 20 most recent bins sorted by timestamp descending. Option A is wrong because it returns error messages, not all messages. Option B is wrong because it counts, not lists individual messages. Option D is wrong because it bins by 5 minutes, not 1 minute.

Answer

The count of ERROR messages per 1-minute interval for the most recent 20 intervals

Answer

The total count of ERROR messages in the log group

Answer

A list of the 20 most recent log entries that contain the word 'ERROR'

Question 5

A company is deploying a new microservice on AWS Lambda. The DevOps team needs to monitor the function for errors and performance issues. Which TWO steps should the team take to set up effective monitoring?

Accepted Answer

Enable active tracing with AWS X-Ray to trace requests through the function. Option A is correct because Lambda automatically sends logs to CloudWatch Logs. Option C is correct because enabling AWS X-Ray traces requests and provides performance insights. Option B is wrong because CloudWatch Agent is not needed for Lambda. Option D is wrong because VPC Flow Logs are for network traffic. Option E is wrong because AWS Config is for configuration management.

Answer

Enable VPC Flow Logs to monitor network traffic to the function

Answer

Enable AWS Config rules to evaluate the function configuration

Answer

Install the CloudWatch Agent on the Lambda execution environment

Question 6

A company runs a critical application on Amazon ECS with Fargate. The application emits structured logs in JSON format. The DevOps team wants to monitor for specific error codes and receive near-real-time alerts. The team also needs to retain logs for 5 years for compliance. Which TWO steps should the team implement?

Accepted Answer

Create a CloudWatch Logs metric filter to count occurrences of specific error codes and create an alarm. Option A is correct because CloudWatch Logs metric filters can parse JSON-structured logs to count occurrences of specific error codes, and you can create a CloudWatch alarm on that metric to trigger near-real-time notifications via SNS. This is a native, low-latency solution for monitoring specific patterns in ECS Fargate logs without additional infrastructure.

Answer

Use Amazon Kinesis Data Analytics to analyze logs in real-time and send alerts

Answer

Enable AWS CloudTrail to log the application's API calls

Answer

Stream logs to Amazon S3 via Amazon Kinesis Data Firehose and use S3 event notifications to trigger alerts

Question 7

A DevOps engineer is designing a monitoring solution for a multi-tier web application hosted on AWS. The application consists of an Application Load Balancer (ALB), EC2 instances, and an RDS database. The engineer needs to capture and analyze HTTP request logs from the ALB to understand client behavior and troubleshoot errors. Which THREE steps are necessary to achieve this?

Accepted Answer

Use Amazon Athena to query the access logs in S3. Option A is correct because ALB access logs must be enabled. Option C is correct because access logs are stored in S3. Option E is correct because Athena can query the logs in S3. Option B is wrong because CloudWatch Agent is not needed for ALB logs. Option D is wrong because CloudTrail captures API calls, not HTTP requests.

Answer

Install the CloudWatch Agent on the ALB

Answer

Enable AWS CloudTrail for the ALB

Question 8

A company runs a critical e-commerce platform on AWS. The architecture includes an Application Load Balancer (ALB) that distributes traffic to a fleet of EC2 instances in an Auto Scaling group. The EC2 instances run a custom Java application that uses an RDS for MySQL database and an ElastiCache Redis cluster for session caching. The DevOps team has set up CloudWatch alarms for CPU utilization, memory, and database connections. Recently, customers have been reporting slow page load times and occasional timeouts. The team notices that during peak hours, the ALB's TargetResponseTime metric spikes, and the number of healthy hosts in the target group fluctuates. The CPU and memory metrics on the EC2 instances remain within normal ranges. The database CPU is also normal. The team suspects the issue is related to the application's session management. Which course of action should the DevOps team take to identify the root cause?

Accepted Answer

Monitor ElastiCache metrics such as CPUUtilization, CacheHits, and Evictions to determine if the Redis cluster is overloaded. Option C is correct because the symptoms (increased latency, fluctuating healthy hosts) and the role of ElastiCache in session caching suggest that Redis performance may be degrading. Monitoring ElastiCache metrics like CPUUtilization, cache hits/misses, and evictions can confirm if Redis is the bottleneck. Option A is wrong because scaling the ALB does not address session management issues. Option B is wrong because database connection pooling is not indicated; database CPU is normal. Option D is wrong because CloudWatch Agent on EC2 would not capture Redis metrics.

Answer

Enable RDS Performance Insights and look for slow queries or connection storms

Answer

Install the CloudWatch Agent on the EC2 instances to collect additional application-level metrics

Answer

Increase the number of ALB targets and adjust the target group health check interval

Question 9

A company runs a serverless application using AWS Lambda, Amazon API Gateway, and Amazon DynamoDB. The application is used by thousands of users. Recently, the operations team noticed an increase in 5xx errors from API Gateway. The team has enabled CloudWatch Logs for the Lambda functions and API Gateway. They see the errors are sporadic and not correlated with high traffic. The Lambda function's error count in CloudWatch is also increasing. The team wants to identify the specific requests that are failing and understand the error details. Which solution should the team implement?

Accepted Answer

Enable AWS X-Ray active tracing on the Lambda functions and API Gateway to capture detailed request traces and error details. Option B is correct because X-Ray provides end-to-end tracing and can capture errors with detailed metadata. It integrates with Lambda and API Gateway to trace requests and identify failures. Option A is wrong because CloudWatch Logs Insights would require querying all logs, which is less efficient for tracing. Option C is wrong because CloudTrail captures API calls, not application-level request details. Option D is wrong because VPC Flow Logs are for network traffic, not application errors.

Answer

Use CloudWatch Logs Insights to query the Lambda logs for ERROR messages and correlate with API Gateway logs

Answer

Enable VPC Flow Logs for the Lambda function's VPC to capture network traffic

Answer

Enable AWS CloudTrail to log API Gateway API calls and analyze the logs

Question 10

A company is using Amazon RDS for MySQL and needs to monitor slow queries to optimize database performance. The team has enabled slow query logs and wants to centralize logging in Amazon CloudWatch Logs for real-time analysis and alerting. Which solution meets these requirements with minimal operational overhead?

Accepted Answer

Modify the DB parameter group to enable slow_query_log and set log_output to FILE, then configure the RDS instance to publish the slowquery log file to CloudWatch Logs.. Option B is correct because publishing RDS MySQL slow query logs to CloudWatch Logs can be achieved natively by configuring the DB parameter group to set 'slow_query_log' to 1 and 'log_output' to 'FILE', then enabling the 'slowquery' log export in the RDS console or CLI. This automatically streams logs to CloudWatch without additional infrastructure. Option A is wrong because Enhanced Monitoring provides OS-level metrics, not slow query logs. Option C is wrong because exporting logs to S3 and then using Lambda to push to CloudWatch adds unnecessary complexity. Option D is wrong because enabling Performance Insights does not automatically send slow query logs to CloudWatch; it provides a different performance schema.

Answer

Enable Performance Insights on the RDS instance and use the Performance Insights dashboard to view slow queries.

Answer

Enable Enhanced Monitoring on the RDS instance and configure CloudWatch alarms based on the metrics.

Answer

Configure the RDS instance to export slow query logs to an S3 bucket, then set up a Lambda function to read the logs and send them to CloudWatch Logs.

Question 11

A DevOps engineer is troubleshooting a production issue where an Application Load Balancer (ALB) is returning 503 errors. The ALB targets are EC2 instances in an Auto Scaling group behind the ALB. The engineer checks the ALB access logs in Amazon S3 and finds that the ALB is healthy. However, the 503 errors persist. Which configuration should the engineer check next?

Accepted Answer

Check the security groups for the EC2 instances to ensure they allow traffic from the ALB on the listener port.. Option C is correct because 503 errors are often caused by the ALB being unable to establish a connection to the targets due to security groups blocking traffic. Checking the target group's health check settings and the security groups for the EC2 instances is the logical next step. Option A is wrong because the ALB is healthy per the logs. Option B is wrong because the issue is not about SSL certificates. Option D is wrong because AWS Shield Advanced is a DDoS protection service, not relevant to 503 errors.

Answer

Enable AWS Shield Advanced to protect the ALB from DDoS attacks.

Answer

Verify that the SSL certificate associated with the ALB is not expired.

Answer

Check the ALB's target group health check settings and verify that the health check path is correct.

Question 12

A company runs a microservices architecture on Amazon ECS with Fargate. The operations team wants to collect custom application metrics (e.g., request latency per service) and visualize them in CloudWatch dashboards. The team also needs to set CloudWatch alarms based on these metrics. Which solution requires the LEAST amount of code changes and operational overhead?

Accepted Answer

Use the CloudWatch Embedded Metric Format to emit custom metrics as JSON log entries.. Option A is correct because the CloudWatch Embedded Metric Format allows applications to emit metrics as structured JSON logs, which CloudWatch automatically extracts into metrics and logs. This requires minimal code changes (just log format). Option B is wrong because publishing to CloudWatch via PutMetricData requires the AWS SDK and more code changes. Option C is wrong because CloudWatch Agent on Fargate is not supported (requires EC2). Option D is wrong because using a sidecar container for StatsD adds complexity and overhead.

Answer

Deploy a StatsD daemon as a sidecar container and configure the application to send metrics to StatsD, then forward to CloudWatch.

Answer

Modify the application code to use the AWS SDK to call PutMetricData API directly.

Answer

Install the CloudWatch Agent on each Fargate task as a sidecar container to collect custom metrics.

Question 13

A company uses AWS CloudTrail to log all API calls in their AWS account. They need to ensure that any changes to CloudTrail configuration (such as disabling the trail or modifying the log file validation) are immediately detected and trigger an automated response. Which solution should the DevOps engineer implement?

Accepted Answer

Create an Amazon EventBridge rule that matches CloudTrail API calls like StopLogging or UpdateTrail and triggers an SNS topic.. Option D is correct because CloudTrail itself logs changes to its configuration, so a CloudWatch Events (now Amazon EventBridge) rule can be created to match API calls that modify CloudTrail (e.g., StopLogging, UpdateTrail) and trigger an SNS notification or Lambda for automated response. Option A is wrong because Config rules can detect configuration drift but are not real-time. Option B is wrong because GuardDuty focuses on security threats, not CloudTrail configuration changes. Option C is wrong because Trusted Advisor does not monitor CloudTrail changes.

Answer

Enable Amazon GuardDuty and configure it to monitor CloudTrail logs for suspicious activity.

Answer

Use AWS Config rules with remediation actions to detect and revert changes to CloudTrail.

Answer

Use AWS Trusted Advisor to check CloudTrail configuration and send alerts via email.

Question 14

A company has a critical application running on Amazon EC2 instances behind an Application Load Balancer. The application is experiencing intermittent latency spikes. The DevOps team has enabled detailed monitoring on the EC2 instances and is using CloudWatch metrics. They notice that CPU utilization and network traffic are normal during the spikes. Which additional diagnostic step should the team take to identify the root cause?

Accepted Answer

Instrument the application with AWS X-Ray to trace requests and identify bottlenecks.. Option B is correct because X-Ray can trace requests end-to-end and identify which component is causing latency, even if CPU and network are normal. Option A is wrong because Synthetics monitors external endpoints, not internal application behavior. Option C is wrong because Container Insights is for containerized environments. Option D is wrong because Trusted Advisor is not a diagnostic tool.

Answer

Use CloudWatch Container Insights to monitor the performance of the EC2 instances.

Answer

Enable CloudWatch Synthetics to create canaries that monitor the application endpoints.

Answer

Run an AWS Trusted Advisor check to identify performance-related recommendations.

Question 15

A company is using AWS Lambda functions for data processing. The operations team needs to monitor the number of invocations, duration, and error counts for each function. They also want to set alarms when the error rate exceeds 5% in a 5-minute period. Which combination of AWS services should the team use to achieve this with minimal effort?

Accepted Answer

Use CloudWatch metrics published by Lambda and create a CloudWatch alarm on the ErrorCount metric with a math expression to calculate error rate.. Option B is correct because Lambda automatically publishes metrics to CloudWatch (invocations, duration, errors, etc.). CloudWatch Alarms can be set on the ErrorCount metric, and a math expression can calculate error rate. Option A is wrong because CloudTrail logs API calls, not function execution metrics. Option C is wrong because CloudWatch Logs Insights is for log analysis, but the metrics are already available. Option D is wrong because Lambda Insights is for detailed performance monitoring but is not necessary for basic metrics and alarms.

Answer

Use AWS CloudTrail to log Lambda invocations and configure CloudWatch alarms on the log events.

Answer

Enable Lambda Insights to collect detailed metrics and use CloudWatch dashboards to monitor error rates.

Answer

Stream Lambda logs to CloudWatch Logs and use CloudWatch Logs Insights to query error rates, then create alarms.