DOP-C02 Exam Dumps : AWS Certified DevOps Engineer - Professional

Comprehensive and Detailed Explanation From Exact Extract of DevOps Engineer documents only:

During an Amazon ECS service deployment, if tasks fail the Elastic Load Balancing target group health checks, Amazon ECS considers those tasks unhealthy and stops and replaces them. This behavior can cause the deployment to remain incomplete because healthy replacement tasks never become available.

Also, if an essential container in the task exits, the entire task stops. Since the question states that the new tasks enter a stopped state soon after launch, an essential container failure is a direct and highly likely cause.

Why the other options are incorrect:

B. The IAM role used by the DevOps engineer to update the ECS service does not need RunTask permission for the tasks to remain running after launch. A permission issue here would more likely affect the update action itself rather than cause launched tasks to stop shortly afterward.

C. Although CloudWatch Logs configuration problems can affect logging, the missing log group is not the most likely direct reason for ECS tasks to repeatedly stop in this deployment scenario.

D. The task role provides permissions to the application code running inside the container. It is not the role primarily responsible for launching the task. Task startup is typically related to the task execution role, ECS service behavior, container health, and load balancer checks.

Installing the CloudWatch agent and instrumenting the application to push custom metrics to the agent is the easiest and lowest overhead method.

Prometheus (B) adds operational complexity.

Lambda polling (C) introduces unnecessary complexity and latency.

Using Logs Insights (D) requires extracting metrics from logs, which is less efficient.

In CodePipeline’s execution mode,

PARALLEL mode for pull_request pipelines ensures that multiple feature branches can be tested simultaneously for quick feedback.

QUEUED mode for main_branch ensures deployments run sequentially — each must finish before the next begins, preventing overlap. This configuration aligns with AWS CodePipeline best practices for trunk-based development and concurrent test pipelines.