AZ-400 Practice Question: Design and implement build and release pipelines
Your team uses GitHub for source control and Azure Pipelines for CI/CD. You need to trigger a pipeline automatically when a pull request is created against the main branch. Which trigger type should you configure in the YAML pipeline?
⚠ Common exam trap
Candidates often confuse `trigger:` (CI on push) with `pr:` (PR validation), especially since both can be used for the same branch, but they serve different events and have distinct YAML syntax.
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
✓
pr:
The `pr:` trigger in Azure Pipelines YAML is specifically designed to automatically start a pipeline when a pull request is created or updated against a specified branch. By default, `pr:` triggers are enabled for all branches; however, to ensure the pipeline only runs for PRs targeting `main`, you configure `pr: main`. This triggers the pipeline on PR creation/update without needing a separate branch policy.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
pr:
Why this is correct
The `pr:` keyword in an Azure Pipelines YAML file defines the branch filters that trigger a pipeline on pull requests (PRs) targeting those branches. This is the correct mechanism for PR validation, as it specifically listens to PR creation and updates, unlike other trigger types.
- ✗
trigger:
Why it's wrong here
The `trigger:` keyword configures CI triggers that run a pipeline on push events to the specified branches. Since the question asks about pull requests, a push trigger does not fire on PR activity, so it is incorrect for this scenario.
- ✗
schedules:
Why it's wrong here
The `schedules:` keyword defines cron-based triggers that run a pipeline at specific times, independent of any code events. It does not respond to pull requests, so it cannot be used to validate PR changes.
- ✗
resources:
Why it's wrong here
The `resources:` keyword declares external resources such as other pipelines, repositories, containers, or packages, and can define triggers for those resources (e.g., pipeline resource triggers). It does not define a PR trigger for the current pipeline, so it is not the correct answer.
Go deeper
Related to this question
Learn chapter
Introduction to DevOps and Azure DevOps
Key term
Branch
A branch is a pointer to a specific commit in a version control system that allows you to work on features or fixes in isolation from the main codebase.
Key term
Pipeline
A pipeline is an automated series of steps that takes code from development to production, ensuring quality and speed.
About these practice questions
Courseiva writes every AZ-400 question from scratch — 823 in total, each with an explanation and a wrong-answer breakdown. None are copied from real exams or dumps. Learn why practice questions differ from exam dumps →
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This AZ-400 practice question is part of Courseiva's free Microsoft 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 AZ-400 exam.