AZ-400 Practice Test 12 — 15 Questions

Question 1

Your pipeline builds a .NET application and runs unit tests. You notice that the pipeline takes too long because it restores NuGet packages on every run. You want to cache the NuGet packages to speed up subsequent builds. Which task should you use?

Choose an answer to begin — your selection is scored in the full session.

Accepted Answer

Cache@2 (CacheBeta). The Cache@2 (CacheBeta) task is specifically designed to cache folders or files between pipeline runs, such as NuGet packages, to reduce restore time. By caching the NuGet packages folder (e.g., $(UserProfile)/.nuget/packages), subsequent builds can skip the full restore and reuse previously downloaded packages, significantly speeding up the pipeline.

Answer

NuGetCommand@2 with the restore command

Answer

CopyFiles@2

Answer

PowerShell@2 to manually download and cache

Question 2

Your company has a large monorepo with multiple microservices. You have a single YAML-based Azure Pipeline that builds the entire solution on every commit to the main branch. The pipeline takes over an hour to complete, causing long feedback loops. Developers often submit changes to only one service, but the whole pipeline runs. You need to reduce build time while maintaining quality. You are considering splitting the pipeline into multiple pipelines, each for a service, and using path triggers. However, some services have dependencies on shared libraries that are updated infrequently. You also need to ensure that integration tests that span multiple services still run when necessary. What should you do?

Accepted Answer

Create separate pipelines for each service with path triggers, and create an additional comprehensive pipeline that triggers only when shared libraries change.. It uses path triggers to run only the pipeline for the changed service, drastically reducing build time. The additional comprehensive pipeline, triggered only when shared libraries change, ensures that integration tests spanning multiple services still run when dependencies are updated, maintaining quality.

Answer

Keep the single pipeline but add caching for dependencies.

Answer

Use a single pipeline but add conditional stages to skip unchanged services.

Answer

Create separate pipelines for each service with path triggers, and disable the comprehensive pipeline.

Question 3

Your organization uses GitHub Copilot for pull request summaries. A developer notices that the AI-generated summary is inaccurate. Which step should the developer take to improve the quality of future summaries?

Accepted Answer

Provide a detailed pull request description. Providing a detailed pull request description gives GitHub Copilot more context and structured input, which directly improves the accuracy of AI-generated summaries. Copilot's PR summary feature relies on the diff and any existing description to infer intent; a richer description reduces ambiguity and enhances the quality of the generated output.

Answer

Disable Copilot for pull requests

Answer

Edit the description after generation

Answer

Ignore the inaccuracy

Question 4

You are configuring Application Insights for a .NET Core web application deployed to Azure App Service. The application must capture telemetry for all HTTP requests, exceptions, and dependency calls with minimal code changes. What should you do?

Accepted Answer

Enable the Application Insights site extension in the App Service 'Application Insights' blade.. Enabling the Application Insights site extension via the App Service 'Application Insights' blade automatically instruments the .NET Core application without requiring any code changes. This extension injects the necessary telemetry modules to capture HTTP requests, exceptions, and dependency calls at the runtime level, leveraging the Azure App Service integration for zero-code instrumentation.

Answer

Configure diagnostics logging in the App Service and stream logs to Application Insights.

Answer

Install the Microsoft.ApplicationInsights.AspNetCore NuGet package and add services.AddApplicationInsightsTelemetry() in Startup.cs.

Answer

Add the Application Insights JavaScript SDK to each page.

Question 5

Which TWO are valid reasons to use a monorepo?

Accepted Answer

Simplifies code sharing and reuse across multiple projects.. A monorepo centralizes all code in a single repository, making it straightforward to share common libraries, utilities, and components across multiple projects without needing separate package feeds or submodule references. Option E is correct because with all projects in one repo, dependency versions are unified and managed in a single set of manifest files (e.g., package.json, requirements.txt), eliminating cross-repo version drift and simplifying coordinated updates.

Answer

Smaller clone size compared to multiple repositories.

Answer

Allows independent CI/CD pipelines for each project.

Answer

Improves security by isolating each project.

Question 6

Your Azure DevOps pipeline deploys a web app to Azure App Service using a YAML pipeline. The deployment fails intermittently with the error 'Conflict' when updating deployment slots. What is the most likely cause?

Accepted Answer

Another deployment or swap operation is already in progress on the slot.. The 'Conflict' error during an Azure App Service deployment slot update indicates that the slot is currently locked by another operation, such as an ongoing deployment or a swap. Azure App Service enforces mutual exclusion on slot operations to prevent race conditions, so if a previous deployment or swap has not completed, the new request is rejected with HTTP 409 Conflict.

Answer

The service connection is using expired credentials.

Answer

The slot name is misspelled in the pipeline configuration.

Answer

The web app is locked by a file handle from a previous deployment.

Question 7

Your team uses Git for source control. You want to maintain a clean commit history on the main branch by avoiding merge commits. Which TWO merge strategies in a pull request achieve this?

Accepted Answer

Rebase merge. A rebase merge (option A) rewrites the commit history of the feature branch onto the tip of the target branch, creating a linear sequence of commits without any merge commits. This maintains a clean, linear history on the main branch. A squash merge (option C) combines all commits from the feature branch into a single new commit on the target branch, also avoiding merge commits and keeping the history clean.

Answer

Merge commit

Answer

Three-way merge

Answer

Fast-forward merge

Question 8

A developer wants to automatically trigger a GitHub Actions workflow when a pull request is opened that targets the 'release' branch. Which trigger should they use?

Accepted Answer

pull_request: branches: [release]. The `pull_request` trigger fires when a pull request is opened, and the `branches: [release]` filter restricts it to PRs targeting the `release` branch. `pull_request_target` also fires on PR open events but runs in the base repository context and is intended for workflows requiring secrets or write access, not as the general PR-open trigger. `push` only fires on pushes to branches, not on PR opens. Therefore, D is correct.

Answer

pull_request_target: branches: [release]

Answer

push: branches: [release]

Answer

workflow_dispatch:

Question 9

A team is designing a release pipeline for a .NET Core web application. They want to deploy to Azure App Service using a blue-green deployment strategy to minimize downtime. Which Azure App Service feature should they use to implement this?

Accepted Answer

Use deployment slots with swap operation.. Deployment slots in Azure App Service support swap operations that enable blue-green deployment by swapping the production slot with a staging slot. This minimizes downtime because the swap is warm-up and validation is done in the staging slot before traffic is redirected, and the swap itself is instantaneous under the hood. No external load balancer or traffic manager is needed because the swap operation handles the routing internally.

Answer

Use Azure Load Balancer in front of two separate App Services.

Answer

Configure auto-scaling rules.

Answer

Use Azure Traffic Manager to route traffic between slots.

Question 10

Your organization uses Azure DevOps and requires that all pipelines enforce branch policy for pull requests. A developer creates a pipeline that builds and tests code on push to any branch. The security team wants to ensure that no code can be deployed to production without passing through a pull request with required reviewers. Which action should you take to meet this requirement?

Accepted Answer

Configure branch policy on the main branch to require a pull request with a minimum number of reviewers.. Azure DevOps branch policies enforce that all changes to the main branch must go through a pull request with required reviewers. This ensures no code can be deployed to production without passing through the defined review process, meeting the security team's requirement.

Answer

Disable CI triggers on the pipeline and require manual builds.

Answer

Modify the service connection to require admin approval.

Answer

Set the pipeline to require approval from the security team before running.

Question 11

Which THREE components are required to set up a self-hosted agent in Azure Pipelines? (Choose three.)

Accepted Answer

A personal access token (PAT) with Agent Pools (read, manage) scope. A personal access token (PAT) with Agent Pools (read, manage) scope is required because the self-hosted agent uses this token to authenticate with Azure DevOps during the configuration step. The agent registers itself into the specified agent pool, and the PAT must have the 'Agent Pools (read, manage)' scope to authorize this registration and subsequent communication.

Answer

An Azure Resource Manager service connection

Answer

An Azure Active Directory account for the agent

Question 12

You need to run unit tests in your build pipeline and publish the test results to Azure Pipelines. Which task should you use?

Accepted Answer

Visual Studio Test task. To run unit tests and publish the results in Azure Pipelines, use the Visual Studio Test task. It executes the tests and automatically publishes the test results to the pipeline, providing rich reporting and pass/fail analysis. The Publish Test Results task is only used when you already have test result files (e.g., JUnit, TRX) from a previous step and need to import them; it does not run any tests itself. The DotNetCoreCLI test command can also run and publish results, but the Visual Studio Test task is the standard framework-agnostic choice.

Answer

DotNetCoreCLI task with test command

Answer

Npm task

Answer

Publish Test Results task

Question 13

Refer to the exhibit. You are deploying this Bicep file using Azure Pipelines. The 'environment' parameter should be set to 'dev', 'qa', or 'prod' based on the release stage. How should you pass the parameter value?

Accepted Answer

Set a pipeline variable named 'environment' and reference it in the AzureResourceManagerTemplateDeployment task's overrideParameters.. The AzureResourceManagerTemplateDeployment task's `overrideParameters` property allows you to dynamically pass parameter values at deployment time. By setting a pipeline variable named `environment` (which can be scoped per stage) and referencing it as `$(environment)` in `overrideParameters`, you can inject the correct value ('dev', 'qa', or 'prod') based on the release stage without modifying the Bicep file or its defaults.

Answer

Define the parameter in the 'parameters:' section of the YAML pipeline.

Answer

Use a task to replace the string '${environment}' in the Bicep file before deployment.

Answer

Modify the Bicep file to include a default value for environment.

Question 14

You are using Azure Pipelines to deploy a function app. You need to automatically roll back the deployment if the post-deployment smoke tests fail. What should you do?

Accepted Answer

Add a stage that runs only when the previous stage fails, executing a rollback script.. Azure Pipelines supports conditional stage execution using expressions like `eq(variables['Build.Reason'], 'IndividualCI')` or `failed()`. By adding a stage that runs only when the previous deployment stage fails (e.g., `condition: failed()`), you can execute a rollback script that reverts the function app to its previous stable version. This ensures automatic rollback upon smoke test failure without manual intervention.

Answer

Configure the pipeline to retry the deployment on failure.

Answer

Use a pre-deployment approval gate to validate the build before deployment.

Answer

Set up a manual validation gate that requires operations to initiate a rollback.

Question 15

You have an Azure DevOps pipeline that deploys to multiple environments. You need to ensure that approvals are required before production deployment. Which pipeline configuration should you use?

Accepted Answer

Define an environment with required approvers for the production stage. Azure DevOps environments allow you to define required approvers for a specific stage (e.g., production). When a pipeline deploys to that environment, it pauses and waits for manual approval before proceeding, ensuring that production deployments are gated by authorized personnel.

Answer

Set the pipeline trigger to 'Manual' only

Answer

Add a 'Manual Intervention' task in the pipeline

Answer

Configure branch policies on the main branch