DOP-C02 Monitoring and Logging Practice Question
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?
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Instrument the application with AWS X-Ray to trace requests and identify bottlenecks.
AWS X-Ray provides end-to-end tracing of requests as they travel through the application. Since CPU and network metrics appear normal, the intermittent latency is likely caused by application-level bottlenecks such as slow database queries, external API calls, or inefficient code paths. X-Ray can trace each request end-to-end and identify the specific service or component introducing delay. Container Insights (B) is designed for monitoring containerized workloads (Amazon ECS/EKS), not EC2 instances directly. CloudWatch Synthetics (C) creates canaries that monitor external endpoint availability and response times, but it does not trace internal request paths. AWS Trusted Advisor (D) offers general best-practice recommendations but is not a diagnostic tool for real-time latency issues.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Instrument the application with AWS X-Ray to trace requests and identify bottlenecks.
Why this is correct
Instrumenting the application with AWS X-Ray creates an end-to-end trace for each user request as it traverses your application, generating a service map and detailed segments/subsegments for each downstream call (e.g., web APIs, SQL queries, external HTTP calls). This lets you pinpoint which specific operation contributes the most latency on EC2, including CPU-bound code vs. I/O wait, and correlate trace data with host metrics. Unlike other options, X-Ray provides the distributed tracing needed to identify and reason about internal request bottlenecks in a complex application.
- ✗
Use CloudWatch Container Insights to monitor the performance of the EC2 instances.
Why it's wrong here
CloudWatch Container Insights is designed for monitoring containerized workloads on Amazon ECS, EKS, and Kubernetes platforms; it aggregates per-container and per-pod metrics, tasks, and services into a single dashboard. Standalone EC2 instances running a critical application are not container infrastructure, so Container Insights provides no visibility into the application's internal request execution or per-request trace segments. It might show host-level CPU/memory via the default EC2 metrics, but that cannot isolate the latency contribution of individual code paths or downstream calls.
- ✗
Enable CloudWatch Synthetics to create canaries that monitor the application endpoints.
Why it's wrong here
CloudWatch Synthetics uses managed canary scripts (such as Node.js or Python) that run from AWS-owned locations outside your VPC to simulate user flows and measure endpoint availability, responsiveness, and functional correctness. While these canaries can detect that a request is slow or failing from an external vantage point, they cannot trace the request inside your application or reveal which internal component, database query, or external service call is the bottleneck. Synthetics answers 'is it reachable and fast from outside?' but not 'why is it slow inside?'—that requires distributed tracing.
- ✗
Run an AWS Trusted Advisor check to identify performance-related recommendations.
Why it's wrong here
AWS Trusted Advisor is a manual, account-level assessment service that scans your resources against best practices for cost optimization, security, fault tolerance, service limits, and performance—but it runs on a refresh schedule, not continuously, and provides static, high-level findings (e.g., overutilized instances, EBS optimization). It does not instrument your application requests, collect trace data, or perform real-time diagnostics, so it cannot identify the specific code path or dependency causing a latency spike. For live, request-level bottleneck identification, you need an observability tool like X-Ray that can trace each individual request end-to-end.
Go deeper
Related to this question
About these practice questions
This DOP-C02 question is part of Courseiva's 1,298-question bank — original exam-style content with full explanations and wrong-answer analysis, never real exam questions or exam dumps. Learn why practice questions differ from exam dumps →
Same concept, more angles
1 more way this is tested on DOP-C02
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. A company is running a web application on Amazon EC2 instances behind an Application Load Balancer. The application is experiencing intermittent errors. The DevOps engineer needs to identify if the errors are caused by the application or the underlying infrastructure. Which solution provides the MOST detailed visibility into the application's behavior?
medium- A.Enable VPC Flow Logs and analyze traffic patterns
- B.Enable AWS CloudTrail and monitor for API errors
- ✓ C.Instrument the application with AWS X-Ray SDK and analyze traces
- D.Enable detailed CloudWatch metrics on the EC2 instances and ALB
Why C: AWS X-Ray traces individual requests as they travel through the application, showing latency, errors, and downstream calls at each segment. This provides the granular, request-level visibility needed to determine whether errors originate in application code or in dependencies like databases or external services. CloudWatch metrics and VPC Flow Logs operate at a coarser level and cannot pinpoint application logic failures.
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This DOP-C02 practice question is part of Courseiva's free Amazon Web Services certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the DOP-C02 exam.