DOP-C02 SDLC Automation Practice Question
A DevOps engineer is configuring a webhook trigger in AWS CodePipeline to automatically start a pipeline when changes are pushed to a specific branch in a CodeCommit repository. The webhook is created and the trigger is set to the 'main' branch. However, when a developer pushes a commit to the 'main' branch, the pipeline does not start. What is the MOST likely reason?
⚠ Common exam trap
A common mix-up: candidates assume the webhook itself directly triggers the pipeline, but AWS CodePipeline relies on CloudWatch Events as the intermediary event bus, so a missing or misconfigured CloudWatch Events rule will break the trigger even if the webhook is correctly set up.
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
✓
The CloudWatch Events rule that triggers the pipeline on repository changes is not configured.
AWS CodePipeline uses Amazon CloudWatch Events (now Amazon EventBridge) to detect repository changes and trigger pipeline executions. When a webhook is created in CodePipeline, it automatically sets up a CloudWatch Events rule that listens for CodeCommit repository state changes (e.g., push to a branch). If this rule is missing, misconfigured, or deleted, the pipeline will not start despite the webhook being present. The webhook itself only registers the endpoint; the actual event routing depends on the CloudWatch Events rule.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
The webhook is not properly registered with CodeCommit due to a conflict with an existing webhook.
Why it's wrong here
Amazon CodeCommit does not maintain webhook endpoints for CodePipeline in a way that would suffer from a registration conflict; it supports multiple triggers, and duplicate registrations are not a common failure. The actual integration for CodePipeline with CodeCommit is based on CloudWatch Events/EventBridge, not a CodeCommit webhook. Therefore, the missing trigger is the EventBridge rule, not a conflicting webhook.
- ✗
The CodeCommit repository is set to send events to Amazon S3, which conflicts with the webhook.
Why it's wrong here
Configuring the CodeCommit repository to send events to Amazon S3 is conceptually impossible because S3 is not an event destination for CodeCommit; CodeCommit sends state changes to Amazon EventBridge or optionally SNS via notifications. The CodePipeline source uses CodeCommit's EventBridge events, and S3 notifications apply only to S3 bucket sources. This does not interfere with pipeline triggering, so it cannot be the cause.
- ✗
The pipeline requires an Amazon SNS notification to be configured for the trigger to work.
Why it's wrong here
An Amazon SNS topic is an optional subscriber for CodeCommit events or a mechanism for manual approval notifications, but it is not a prerequisite for CodePipeline's webhook or EventBridge-based trigger. CodePipeline directly receives CodeCommit changes through EventBridge without SNS in the path. Thus, the absence of an SNS topic does not stop the pipeline from being triggered.
- ✓
The CloudWatch Events rule that triggers the pipeline on repository changes is not configured.
Why this is correct
For CodeCommit-based pipelines, CodePipeline relies on an Amazon CloudWatch Events (EventBridge) rule that listens for repository state changes, such as a branch reference updated to a specific branch name. If this rule is absent or disabled, the webhook may exist but no events are routed to the pipeline, so pushes to the repository will not trigger a new execution. Configuring or restoring this rule is the required fix.
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Written by Johnson Ajibi, MSc IT Security
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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.