AZ-400 Timed Practice Test 3 — 10 Questions

Question 1

A team uses a monorepo in Azure Repos. They want to implement a build validation policy that only triggers builds for code changes in specific folders to reduce build times. Which approach should they use?

10 minute time limit — choose an answer to begin.

Accepted Answer

Configure the build policy in Azure Repos with a path filter to limit which folders trigger the policy.. Azure Repos build validation policies allow you to specify path filters when configuring the policy. These path filters restrict when the policy requires a build, based on the files changed in the pull request. By setting the path filter to the specific folders of interest, the build validation only triggers for changes in those folders, directly reducing build times for unrelated changes. Pipeline trigger path filters (Option D) control CI builds on push, not the build validation policy for pull requests.

Answer

Use a manual trigger and have developers specify which folder to build.

Answer

Create separate YAML pipelines for each folder and configure branch policies to require all pipelines.

Answer

Configure path filters in the pipeline trigger to include only the changed folder.

Question 2

Your release pipeline deploys a .NET Core web app to Azure App Service using a slot swap strategy. The pipeline runs acceptance tests on the staging slot before swapping. After a recent change, the acceptance tests pass but the production site becomes unresponsive after the swap. What is the most likely cause?

Accepted Answer

The staging slot had different app settings that were swapped into production, causing the site to fail.. The most likely cause is that the staging slot had different app settings (e.g., connection strings, environment variables, or feature flags) that were swapped into production. During a slot swap, Azure App Service automatically moves all slot-specific configuration (app settings, connection strings, and other deployment slot settings) to the target slot. If the staging slot was configured with settings intended only for testing (like a staging database or debug mode), those settings would overwrite the production settings, causing the production site to become unresponsive. This is a common pitfall because acceptance tests may pass against the staging environment but fail when the same code runs with production configuration.

Answer

The acceptance tests are not comprehensive enough and missed a regression.

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The acceptance tests should have been run after the swap.

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The slot swap was not 'warm-up' and caused downtime.

Question 3

Your organization uses GitHub for source control and GitHub Actions for CI/CD. You need to implement a branching strategy where every commit to the main branch triggers a build and deployment to a staging environment, but only after a successful pull request review. Which GitHub Actions trigger should you use?

Accepted Answer

push with branches: [main]. The `push` trigger with `branches: [main]` runs on every commit pushed to main. When branch protection requires pull request reviews, commits only reach main through a reviewed and merged PR, so this satisfies the 'only after successful pull request review' condition. In contrast, `pull_request_target` with `types: [closed]` triggers for any closed PR, including those not merged, and does not map one-to-one to commits on main. To use a PR event, you would need an additional condition like `if: github.event.pull_request.merged == true`, which is not mentioned.

Answer

pull_request_target with branches: [main] and types: [closed]

Answer

pull_request with branches: [main]

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workflow_dispatch

Question 4

Which THREE conditions must be met for you to use the 'Approvals' feature in Azure Pipelines to control deployments to a production environment? (Choose three.)

Accepted Answer

The approver must have the 'Approve pipeline permissions' permission for the environment.. The 'Approvals' feature in Azure Pipelines requires an environment to be defined in the pipeline. You must add an approval check to that environment, which can be done in either a classic release pipeline or a YAML pipeline that references the environment as a resource. Additionally, the approver(s) - whether individual users or groups - must have the 'Approve pipeline permissions' permission on that environment. Without an environment resource, the approval check cannot be configured; without the permission, approval requests cannot be validated.

Answer

The approver must be an individual user, not a group.

Answer

The approval must be configured in the release pipeline's pre-deployment conditions.

Question 5

Your organization uses GitHub and wants to implement a monorepo strategy for multiple related projects. Which approach best optimizes CI/CD pipeline performance by only building projects that have changed?

Accepted Answer

Use path filters in GitHub Actions workflows. GitHub Actions path filters (using `on.push.paths` or `on.pull_request.paths`) allow you to trigger workflows only when changes are made to specific directories or files. In a monorepo, this ensures that CI/CD pipelines run exclusively for the projects that have been modified, avoiding unnecessary builds and significantly improving performance.

Answer

Use a single workflow that builds all projects on every push

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Use submodules to separate projects

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Use workflow templates and composite actions

Question 6

Your team uses Azure Repos for source control. You need to enforce that all builds must pass unit tests before code can be merged into the main branch. Which branch policy should you configure?

Accepted Answer

Add a build validation policy that triggers the CI pipeline and requires it to succeed.. Azure Repos branch policies allow you to add a build validation policy that triggers a CI pipeline (e.g., a YAML or classic build pipeline) and requires it to succeed before a pull request can be completed. This ensures that all code merged into the main branch has passed unit tests, enforcing quality gates directly in the PR workflow.

Answer

Require a linked work item.

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Require a minimum number of reviewers.

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Require comment resolution.

Question 7

Drag and drop the steps to perform a blue-green deployment in Azure using App Service slots into the correct order.

Accepted Answer

1. Create a staging slot, 2. Deploy the application to the staging slot, 3. Validate the staging slot, 4. Swap the staging slot to production, 5. Monitor the production slot. Blue-green deployment involves creating a slot, deploying to it, validating, swapping, and monitoring.

Answer

1. Deploy the application to the staging slot, 2. Create a staging slot, 3. Validate the staging slot, 4. Swap the staging slot to production, 5. Monitor the production slot

Answer

1. Create a staging slot, 2. Deploy the application to the staging slot, 3. Swap the staging slot to production, 4. Validate the staging slot, 5. Monitor the production slot

Answer

1. Create a staging slot, 2. Deploy the application to the staging slot, 3. Validate the staging slot, 4. Monitor the production slot, 5. Swap the staging slot to production

Question 8

Refer to the exhibit. A build pipeline uses this trigger configuration. A developer pushes a commit to the 'main' branch that modifies files in '/src/app/' and '/src/tests/'. How many builds will be triggered?

Accepted Answer

1 build, because batchChanges is true.. The trigger configuration has `batchChanges` set to `true`. When `batchChanges` is enabled, Azure Pipelines groups all commits that arrive while a build is in progress into a single build, rather than triggering a separate build for each commit. In this scenario, the developer pushes a single commit that modifies files in both `/src/app/` and `/src/tests/`. Since `batchChanges` is true, only one build is triggered for that commit, regardless of the number of modified folders.

Answer

0 builds, because the excluded path takes precedence.

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3 builds, because maxConcurrentBuildsPerBranch is 1 but batchChanges overrides.

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2 builds, one for each modified folder.

Question 9

A company uses Azure Pipelines to build a .NET Core application. The build takes 45 minutes due to dependency restoration. They want to reduce build time. What is the most effective strategy?

Accepted Answer

Cache the NuGet packages and enable caching in the pipeline. Caching NuGet packages in Azure Pipelines is the most effective strategy because dependency restoration is the primary bottleneck, often downloading hundreds of packages from nuget.org. By caching the ~/.nuget/packages folder, subsequent builds skip the network download entirely, reducing the 45-minute build time to minutes. This directly addresses the root cause—repetitive package restoration—without requiring additional infrastructure or parallelism.

Answer

Use parallel jobs in the pipeline

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Use a self-hosted agent with more CPU

Answer

Enable incremental builds

Question 10

Your organization uses Azure DevOps to manage CI/CD pipelines. The security team requires that all pipeline runs use a specific service connection that references a managed identity in Microsoft Entra ID. However, some developers have been using personal access tokens (PATs) in their pipelines, bypassing the managed identity. What should you implement to enforce the use of the managed identity service connection?

Accepted Answer

Use a pipeline decorator to validate the service connection and fail the pipeline if an unauthorized connection is used.. Pipeline decorators allow you to inject custom validation steps into every pipeline run at the organization or project level. By using a decorator that checks the service connection ID used in each job and fails the run if it does not match the approved managed identity connection, you can enforce compliance without relying on developer cooperation or manual policy configuration.

Answer

Configure a branch policy on the main branch to require a specific service connection.

Answer

Restrict the use of PATs by setting an agent pool-level permission.

Answer

Store the service connection ID in a variable group and reference it in each pipeline.